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pH - Science topic

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I dissolve 2 mol/liter of Fecl3,6H2O and engineered biochar. finally, its pH value becomes negative. what is the factual background of this process? How much NaOH should I add to neutralize?
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Sir, It's possible. If the molarity of hydrogen ions is greater than 1, you'll have a negative value of pH. For example, you might expect a 12 M HCl solution to have a pH of -log(12) = -1.08.
Similarly these articles may be helpful to you:
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I'm studying heavy metal adsorption with some absorbents.
But At the adsorption isotherm experiment,
The pH decreased by increased concentration in the solution...
Is it normal Common phenomenon?
I couldn't find a paper that considers this phenomenon...
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Sorry to make you misunderstand.
I already adjusted the pH of all solutions that were used in the adsorption experiment.
I mean, even I did adsorption experiments with the solution adjusted the same pH, the pH of the solution after experiments were decreased by the concentration
(For example, the initial pH of the solutions were 5
And concentrations of the solutions were 5, 10, 20, 50, 100 mg/L .....
But the pH after adsorption experiments were 4.7, 4.6, 4.5, 4.4....
I don't know why the pH of the solutions was changed by the concentration after adsorption experiments.)
Thank you for helping me again.
But Could I get more information????
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Murphy and Riley's colorimetric methods are suitable for alkaline samples. For sediment extracted with strong acids (pH of the supernatant is 0.8-5), what method and solution are suitable for colorimetry?
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I respectfully correct your statement the Murphy and Riley is suitable for alkaline solutions: the reaction occurs under acidic conditions
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Hello,
I'm designing a generic HILIC gradient to separate a complex mixture containing an unknown metabolite of interest for structure elucidation. The properties of the metabolite are unknown beyond its molecular weight and when it elutes on a C18 reverse-phase column (it is a polar molecule). I'm having difficulty finding online what a good buffer and pH is for a generic HILIC gradient, does anyone have any suggestions? I'll be using ACN and H2O as my solvents. My column is a Poroshell 120.
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Regarding pH, this partly depends on which Poroshell 120 HILIC resin you're using - the HILIC-z can go up to pH 12 while the other two top out around pH 7.
Otherwise, retention time in HILIC increases with compound ionization, so you will resolve this metabolite from less polar background better at a pH where it is ionized (see if you can find pKa value(s)). If it is a complex/diverse mixture of analytes, I'd use something between pH 5-7. 10 mM ammonium acetate with 0.02% acetic acid might work (~pH 5). If you need to go more acidic, you can try 10 mM ammonium formate with 0.2% formic acid (pH3).
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Murphy and Riley's colorimetric methods are suitable for alkaline samples. For sediment extracted with strong acids (pH of the supernatant is 0.8-5), what method and solution are suitable for colorimetry?
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Please refer to the book on soil chemical methods by M.L.Jackson,1973
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I synthesized Hydroxyapatite by wet chemical precipitation process with the help of a phosphate and calcium precursor and maintaining the pH of the solutions after mixing at different values using an alkali solution. I found that the percentage yield of hydroxyapatite varies with varying pH values while rest of the synthesis parameters were kept constant throught the synthesis process. What may be the exact reason for this variation in the yield of HA with varying pH? Thanks in advance.
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Have a look at the Pourbaix diagram for your system. For example, Figure 1 in the attached. This tells you which species are stable at which pH. You'll find that there's a pH region where hydroxyapatite (not upper case) is the dominant and stable species.
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Farmers of western Rajasthan face a lot of problems due to saline-alkali soils and poor quality irrigation water. Any instruments developed so far or any techniques may be suggested
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Soil salinization may occur through both natural and anthropogenic reasons. Out of 932.2 million ha salt-affected soils worldwide, the extent of human-induced salinization is 76.6 million ha . Arid and semi-arid regions, where evaporation rates are high and fresh waters are scanty to flush out the excess salts from soil, favor the formation of such soils. The various processes of soil salinization and practices to be followed in raising crops have been extensively reviewed .
Please have a look at enclosed PDFs...
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I am utilizing different kind of clay in my experiment but its pH is biggest hurdle as working environment is acidic and when this clay is mixed with other material ,its not properly working i.e. its loosing its inherent properties . So I am looking for pH reducer (not acidic like H2SO4/ HCl). when I am utilizing acidic material my clay properties drops drastically.
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Thank you very much.
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I'm trying to make a solution for haptoglobin measurement using this product. My method gives me the following directions:
0.6g o-dianisidine, 13g sodium phosphate monobasic and 0.5g EDTA dissolved in 1l deionised water, pH adjusted to 4.1.
I know that o-dianisidine is only slightly soluble in water (60mg/l) but possibly more soluble under acidic conditions however it still did not totally dissolve when at pH 4.1
If I dissolved in alcohol, approx (50ml) does anyone know if the addition of the alcohol to my buffer will affect the assay result ?
Anyone have experience with this colorimetric assay for haptoglobin? solving the same amount in
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Hello Alison, did you been able to disolve O-dianisine in your haptoglobin determination experiments?
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I prepared a pea protein solution (pH≈7) and used the DSC to characterize the denaturation peaks. I run the DSC twice for the same sample. In the first run, I heated the sample from 25 to 130℃ and kept it at 130℃ for another 30 min. After cooling, I perform a second run. However, I found the DSC profiles of pea proteins didn't change, which is inconsistent with previous literature. What's the problem? Thanks!
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Hello Zhiyun,
We are FOODENGINE (An integrated food quality research and training programme (foodengine.eu)), a research network of young researchers, leading european universities and industrial partners funded by the EU. We work on plant-based solutions for foods – including analysis of pea and fava bean proteins using DSC.
We could propose you to maybe rethink on the type of reference you are using in your analysis – also if you give the 'suspension' time to hydrate the proteins before the analysis is conducted. Moreover, is the protein a commercially produced one? It could also have been denatured (by heat treatment or drying). Maybe looking into the details might help.
Please feel free to contact us if you have a specifc question.
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Hi, Recently, we bought BCIP/NBT (B1911) of Sigma, before, we've used the same reactives of Roche and that reaction are mixed with Phosphatase Buffer - pH 9,5. Now, we don't know if B1911 is used with Phosphatase Buffer, we looking for the datasheet in webpage but the information is not sufficiently clear and comprehensive, Can you help me about the protocols for Western Blot?. Thanks
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Hi Luisa Fernanda,
We use the BCIP-NBT from Amresco (E116-100ML). In our protocol, after the antibody step, we perform 4 washes to the nitrocellulose membrane for 5 min each with the solution (0.5 M NaCl, 2 mM Tris-HCl pH 7.4, 0.1% Tween 20), followed by a last wash for 1 min with saline, and once completely discarded, we add the BCIP-NBT and leave for 30 min in slow stirring and darkness, then discard it and leave the membrane in distilled water to stop the reaction.
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How can we say whether the solubility of Ar is more or less than CO2. To be precise how many times more or less is the solubility of Ar in Sea water than CO2?
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Outside my field, but the comparison must be made under conditions acidic enough so that only CO2 is present, unless there is some smart modelling
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Here are the details to the experiment
Innoculum : Thickened Sludge
Feed : Synthetic acetic acid and butyric acid
Reactors : CSTR reactor with working volume of 11L
pH at the start of my experiment : 7.4
I collect samples from the reactor everyday to check the pH of the system, and even though I'm feeding it synthetic organic acids around the pH of 3, the overall pH of the system steadily increased and now it's around 9.
My theory for the increase in pH is
1. The CO2 production caused production of bicarbonates
2. Some part of methanogenesis increases pH heavily.
If there's anyone who has had a similar experience please let me know.
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Organic nitrogen is converted to ammonia through ammonification by a process called hydrolysis. Subsequently, ammonia reacts with carbon dioxide produced during anaerobic digestion to form ammonium bicarbonate which contributes to alkalinity in the reactor (Shende and Pophali, 2020). I suggest you to check TKN and NH3 both in the thickened sludge (feed). Also, make sure that the VFA/Alkalinity ratio should be kept below 0.4 in the reactor.
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I have PEGylated antibody in 6.5 pH phosphate buffer. I want to show change in molecular weight using SDS PAGE. While preparing the sample should I change the buffer of my sample to TRIS-HCl pH 8.8 or pH 6.8? My concern is if the pH 6.5 will affect the running process or not.
Thanks.
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Thank you :) I am running the gel. I will update the result.
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In many papers, PBS (pH = 7.4) is used to bind carbon dots and aptamers. Why?
Is it related to pH at which aptamer binds well?
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Yes!
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I prepared medium with DMEM powder (Cat#D5468, Sigma) and add NaHCO3 (3.7g/L). Since the pH will fluctuate due to CO2, should I adjust the pH of DMEM when I prepare it or not?
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Yes , can use HCl for adjusting pH, when use NaHCO3 ...
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During Elution of protein (say an Antibody) from Protein A column using Elution buffer which is at low pH (3 to 4) and immediately adding Neutralization buffer to the collected fractions to prevent the negative effects due to this extreme low pH. I'ld like to know during this process will the protein remains in native form only (or) It will first unfold during low pH elution fallowed by re folding during neutralization ?
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Hi there,
Neutralizing the pH as quick as possible limits the denaturating effect of low pH on proteins. It's not about denaturation/renaturation processes, it's rather about preventing denaturation.
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I am currently working on Lactobacillus salivarius for an eventual bacteriocin production, I don't adjust the pH of the supernatant when realizing the deep well diffusion agar test. To check wether the prior inhibition effect of the supernatant is due to pH or to other inhibitors in the supernatant, I prepared a control of MRS-Broth-HCl solution at a pH of 4 that I tested against the same bacteria. At the same time and same plate, I tested again the supernatant that I have also at pH 4 , and surprisingly I got an inhibition only for the MRS-HCl and nothing with the supernatant, even though it is by pH 4 . Do you have any suggestion that may help ? Thank you very much !
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The role of conductivity concentration increases or decreases in the ANAMMOX WWTP in terms of nitrate, nitrite, ammonium and also pH. It affects more or less.
Can ignore the conductivity or it helps in understanding the behaviour of the SBR tank?
Your answer is valuable to me.
Thanks
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Hi Alam,
Conductivity may help to understand the SBR tank and may be an easy and simple method to monitor the nitrogen removal processes. In my experience this parameter is corelated with ammonium and inorganic nitrogen forms concentration and conductivity plots are parallel to the plots of analysed nitrogen forms (i.e. conductivity increase with N-NH4 concentration). When the ammonium ions are converted during the processes to nitrogen gas molecules then process performance could be followed by conductivity measurements. The relationship is strongly dependend of type of wastewater, and other compounds concentration, so the good way is to experimentaly compere changes in ammonium compounds concentrtation and conductivity for each reactor and wastwewater type.
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I am having an issue with measuring the pH of my media.
I use D-MEM/F12 media (without buffer) and try to adjust it to pH = 7.4.
Since I incubate it @ 37C / 5% CO2, I added 2.5 g/L of NaHCO3 (based on
However, the rapid change of pH due to air exposure prevents me from obtaining a reliable result. I did try to use 15ml open tubes for the incubation, which I tightly close before removing from the incubator to limit air exposure, but it does not seem to do the trick.
Any ideas/creative solutions?
Thanks
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Interested
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I'm currently using HEK293T cells. Most spinfection protocols I have found did not state clear about if CO2 is needed during the spinfection in centrifuge after cells and virus are mixed. As 5% CO2, usually from the incubator , is necessary to maintain correct pH, would complete DMEM containing 5% CO2 be needed?
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yes why not.
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According to Kokubo's instuction for preparing SBF (Simulated Body Fluid) pH should be increased from 2.0 to 7.4 after adding Tris to the solution. I added all additives one by one, and the pH became 1.8-1.9 right before adding Tris. But then after adding Tris it didn't increased.
Does it mean the Tris composition is wrong? or Should I consider something especial in adding Tris?
(The Kukobo's paper has been attached.)
Thank you so much in advance for your replies.
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The original SBF solution, which can be named c-SBF, is a TRIS-HCl pH-buffered solution (pH = 7.40 at 37 ºC) that can be prepared as indicated at Table 5.1 (p. 206) of the following reference:
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Hi every one,
I am extracting enzymatic extract from plant (50 mM Sodium phosphate buffer (pH 7.8), 0.1 mM EDTA, 0.1 % (v/v) Triton; 1 mM PMSF). I mesure the protein content and enzymatic activity fom this extract.
So I want and I need to know if the enzymes extract can be conserved for further enzymatic activity measurement (SOD, CAT, APX, ...).
I really need your help, thank you very much
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I have been successfully storing at -80 °C, making a separate working solution for other immediate assays, to avoid multiple freeze-thaw.
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We would like to identify the % ratio of heavy metal ions species in water solution according to pH and concentration; for example: Cu2+, Cu(OH)+, Cu(OH)2.... Could you recommend a suitable software in this case? Thank you!
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Dear Yurii V Geletii and Kafia Oulmi. Very great, thanks for your strong support!
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I want to apply a difunctional electrode in H-type two-electrode cell. I would want to know that if there is any way to use different pH electrolytes in the H-type two-electrode cell? Like 0.5 M H2SO4 on one side, 1M KOH on the other side? If there is possible, which ion exchange membrane should I choose?
And I am looking for an article which topic is about organic oxidation at the anode in 1M KOH and hydrogen generation at the cathode in 0.5M H2SO4. I appreciate that if you could tell me the name of similar articles.
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Dear Haoyue Zhang,
Can you deliver a better description of your system? Are you performing potentiometric measurements or promoting chemical reactions with the electrical current?
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I am stir washing (powdered) biochar aqueous solution. Washing is meant to increase the pH of the solution from 0.1 to 6. Each wash is carried out for one hour. Then 90% of water is drained and refilled with fresh deionized water and temp is maintained at 70C. If I run out of deionized water, using distilled water is equally good and will serve the purpose stated above?
Input please?
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Both are pure water, but deionised water is far pure than disilled water. Earlier responses have very well covered the answers. . The only difference between the two is, distilled water will still conduct electricity , while deionised will not conduct any electricity.....
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I was doing DNA precipitation (after phenol-chloroform) with 2.5x volume 100% ethanol, 1/10 3M sodium acetate pH 5.2 at -80C freezer for 2h. After the incubation, the solution kind of half froze and turned into a glycerol-like consistency. I have a feeling this is not normal and the solution should be watery? What do people think?
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I think it is normal!
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Dear Scientists,
Just to inquire on the potential of Hydrogen (pH). Is there a solution or substance with pH beyond 14? From primary school to university, we learnt that pH ranges 1 to 14. Where 7 is neutral, 1-6.9 acidic and 8- 14 is alkaline.
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Dear Bruce Robin Nyamweha, there are many things to correct in the above statment. The conventional pH range is from 0 to 14. Both above and below this pH range do exist for strongly acidic and basic chemicals, respectively. Please check the following documents. My Regards
10.1021/ed083p1465
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I am trying to increase the pH of a powdered biochar aqueous solution up to 6 by stirring/washing with de-ionized water. The starting pH was 0.1. The initial weight of biochar powder was about 200 g and it was taken in 500 ml glass beaker and beaker was filled up with DI water. The temperature is kept at 70C and stirring is done for 01 hour, then I take off the beaker, let the powder settle down, drain the 90% of water from top, refill the beaker with DI water and repeat the stirring. I achieved a pH of 4.2 in about 35 washes but after that pH is not increasing and is staying at 4.2 even after 80 plus washes.
Any reasons or suggestions are requested for the stated problem please?
Regards....
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agreed with Tariq Mehmood
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It is well known that increased atmospheric carbon dioxide has increased marine pH. Is there any evidence that increased atmospheric carbon dioxide has increased the pH of soils and/or caused any other land consequences due to changed pH.
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The question is incorrect. Generally, increase in CO2, whether from the atmosphere or soil itself decreases pH. Many literature available.
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Research problem purpose
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Presence of water soluble or exchangeable calcium in acid soils is difference than presence of lime . The pH optimum for precipitation of calcium as carbonate will be much higher than its precipitation as either calcium chloride , calcium silicate or even calcium hydroxide...
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To adjust the pH 6 on the estimation of dietary fiber
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It is not necessary to store the solution at 4oC. It is stable at room temperature indefinitely. Crystallization of a1 M solution may occur even at room temperature, but a 0.5 M solution should not have this issue.
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We are trying to making nano ferrites like Zinc, Nickel, cobalt, copper, etc. via the hydrothermal method. In some cases, I am facing problems to maintain the pH of the solution, need to maintain the pH in a basic medium so all experts please put your opinion.
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Dear Shubang Vyas, it depends essentially on the Synthesis process (sol-gel, précipitation, hydrothermal, ...). The following documents deals with some examples. My Regards
DOI: 10.5772/intechopen.80667
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I have tried below this procedure but it won't work
so, I need new protocol
Procedure for estimation of CaCO3 in sediments
Preparation of reagents:
  1. Standard EDTA (salt) of 0.01M: Take 3.7984g of EDTA and dissolve in l liter of distilled water.
  2. ? Standard Ca+ (CO3) solution: Take approximately 3g of CaCO3 in a beaker and keep it in a desiccator for a few hours. Then weigh 0.25g and transfer it to a 150ml beaker. Add a few drops of HCL (½ to 1ml). Once the effervescence (escape of gas from an aqueous solution) stops, make it to 100ml with distilled water in a standard flask.
  3. NaOH solution/KOH solution of 8M: Dissolve 320g of NaOH in ~500ml of distilled water. Then make it up to 1 liter or dissolve 488g of KOH using distilled water and make up to 1 liter.
  4. Patton and Reeder's indicator (HHSNNH): mix 0.5g of the indicator with 50g of Potassium chloride (KCL) and using a mortar and pestle to power them as fine as possible (face powder).
  5. ? Hydroxylammonium (hydro)chloride.
  6. Triethanolamine.
  7. pH paper: use pH paper ranging from 0-14 (Whatman pH paper)
Procedure for calcium carbonate estimation:
  1. Take 0.1g of dried sample into a beaker, add 25ml of hot 1N HCL (36 ml of HCL in 1 liter) and wait for 10 min.
  2. Filter the solution and make the volume to 50ml with distilled water.
  3. Add 5ml of 8M KOH /NaOH and stir well and make sure that pH is ≥ 12, if less add up a few drops of NaOH /KCl.
  4. Then add 1ml triethanolamine and 30-50 mg of Patton and Reade’s indicator solution which turns the color of the solution to wine red.
  5. Titrate against EDTA till the blue color of the solution appears. Note down the burette reading which is equal to the amount of CaCO3(%).
CaCO3= volume of EDTA solution drawn down.
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Bachir Achour Thank you sir for your immediate response. It's very helpful.
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Hi,
I wonder if it is possible to find natural soil carbonates (calcite, dolomite, etc.), not coming from liming, in soils naturally having a low pH (4-5.5).
Is it possible to find these mineral forms of C in acidic tropical soils?
I am asking because while measuring both total C and inorganic C (after acid dissolution) of tropical soil samples from Indonesia with an Elementar, I sometimes get a gap between the two measurements.
Sometimes the gap is positive (total C > organic C), and other times the gap is negative (organic C > total C !?). Generally, total C is equal to organic C, meaning most samples do not show these confusing 2-way gaps, and suggest the absence of inorganic forms of C.
In both cases, I wonder if discrepancies are just technical (noise), or if the gaps between samples are due to the natural variability of my samples, or in some cases, there could be some carbonates present in those soils (which have a relatively low pH of 4-5).
Best,
Thomas
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I dont think , it is possible to find any carbonates in acidic soils , considering the critical pH for precipitation of carbonates as 8.2 , except the pedogenic carbonates deposited deep into the sub-surafce of acidic soils . Ironically , maximum deposits of limes /dolomites are reported from acid soil belts only....
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I have to perform WB on FFPE tissue. I've already done several attempts and the result is always the same. Can you help me understand why the bands are like this and not neat? Standard is fine (I didn't put it this time but it worked fine every time), so something went wrong before.
Some information:
- It's dog breast cancer tissue
- Deparaffination was done with xylol and a series of alcohols (there was a series of steps with centrifuging and vortexing involved)
- Pellet weight was 45 mg
- I put 100 microliter of buffer in each tube
- It was all pretty homogenized
- I tried different buffers: (1) 200 mM tris-HCl, pH 7.5, 200 mM NaCl, 5% SDS, 100 mM sodium citrate; (2) 200 mM tris-HCl, pH 6.8, 20% glycerol, 2% SDS
- I incubated the samples in a Thermobloc with a shaker for 20 minutes at 99°C and for 2h at 80°C at 100 rpm
- The gel ran for 30 minutes at 200 V
- Running buffer was already done from Bio-Rad (Tris-glycine-SDS): it was diluted depending on the manufacturer's instructions
- The materials (including gel and running buffer) are pretty old, but they told me that they should work anyway and that the problem is probably another one
I'm a beginner in laboratory, so you can say everthing that comes to your mind, even if it's something obvious.
Thanks for your help
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Hi Martina, unfortunately without coomassie it is difficult to understand something, the coomassie it is not expensive and you can recycle the solution as for ponceau. If you don't understand the problem you waste your time and money without reason. Maybe you can convince your PI to buy at least the coomassie.
If you use only the bromophenol as "marker", as you said, it can't explain if the problem is the samples or even in the laemmli.
At this point you can proceed with the transfer and stain with ponceau.
Valeria
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SCMs: Supplementary Cementitious Materials
CH: Portlandite (calcium hydroxide)
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In the hydration process of cement C2S and C3S react with water to form C-S-H gel and CH (Ca(OH)2). Due to presence of aforementioned CH in concrete makes it high alkaline in nature having pH 13. By adding SCMs in concrete, it react with CH (which is formed in hydration process) and water to produce additional C-S-H gel. This reaction is called pozzolanic reaction. Due to formation of additional C-S-H in SCMs concrete show higher strength than conventional concrete. But consumption of reserved level of CH in pozzolanic reaction reduce pH value of concrete (<13).
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How to compute physical properties (thermodynamic parameters like free energy and kinetic parameters like rate) at different pH using computational software?
Suggestions of software/open source codes that can handle the problem is highly appreciated.
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It is a quite gross question ! . You should be more precise about your physico-chemical experiment . For eg HBZ distribution with variation of enthalpy / K1/K2 -ratio determination of ester hydrolysis at different acid concentration ( pH ) you can collect your dataset . With the specific equation modelling you can somply execute FORTRAN90 , C, C++ - https://www.researchgate.net/post/FORTRAN_vs_C_a_comperative_approach
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I'm planning on doing research by using anaerobic digester with liquid substrate and want to see its pH changes periodically. Any suggestion on measuring the pH with maintaining its anaerobic condition? Thanks.
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Aldyon Azkarahman there are various ways one can check it either with the readily available pH paper testing paper or the pH meter or the sensors/probes which are available can be installed where the slurry comes in contact with the probe and online readings can be seen on the meters or the can also be connected to the the panels/plc
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Effect of swine waste in watershed such as Biochemical Oxygen demand, Total suspended solid,pH, color, nitrate, Phosphorus.
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Solution A: 0.2 M NaH2PO4 solution Weigh 31.21 g of analytically pure NaH2PO4*2H2O and dilute to 1000 ml with distilled water.
Solution B: 0.2 M Na2HPO4 solution Weighed 71.64 g of analytically pure Na2HPO4*12H2O and dilute to 1000 ml with distilled water.
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You can weigh 35.5g of Na2HPO4 and dissolve in 500mL to make a stock solution 1. Also weigh 30g of NaHPO4 and dissolve in 500mL to make another stock solution 2. Take 80mL from the first stock into a container and make up the volume to 400mL. Take 30mL from the 2nd stock and make a volume of 150mL. Finally, take from the 150mL solution and add to the 400mL solution until you get the desired pH.
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I'm relatively new to patch clamp, but I've been working extensively on optimizing our recording parameters for studying sEPSCs in adolescent rat CA1 pyramidal cells. My biggest hurdle has been consistent cell health in my slices. Some days, cells go to gigaohm almost instantly upon releasing positive pressure and applying minimal negative pressure. Other days, I cannot get a seal above 250 MOhm. I am currently using Jonathan Ting's NMDG and HEPES based solutions since I have had better luck with this method than traditional cold sucrose slicing. Osmolarity and pH are always properly adjusted (300-310 mOsm; pH 7.3-7.4), and solutions are well saturated with carbogen prior to slicing and recording. Each animal undergoes transcardial perfusion before slicing. I have tried slicing in both frontal and horizontal planes, and horizontal slices seem to produce the best cell health. However, I prefer the orientation of frontal slices when targeting this cell type since dorsal hippocampus has been used for many of our past experiments (field recordings, etc) and since the PC layer is so much more prominent. Lastly, I am using a Cs-gluconate based internal solution. At most, I can get 3 cells per day. Some days though, I cannot get a single acceptable recording. I guess I'm just looking for any tips from veterans of patching that may improve my throughput in these experiments. It is well known that patching older animals is sometimes a challenge, but surely I can improve what I'm doing in some way. I'm happy to provide any further details should the need arise. Thank you in advance for your suggestions!
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Patching with cesium-based solution is always difficult. When I've used straight cesium internal, I've had the worst time getting gigaohm seals. Clearly much worse than with potassium internal.
One thing that I've found helps is replacing some of the cesium with potassium -- say 2/3 cesium and 1/3 potassium. If you still get good space clamp with this (somewhat) diluted mixture, your data yield might go up considerably.
Good luck.
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What is the most appropriate system that simulates the physiological system (pH 7.4) for studying E/Z isomerization (inversion) of small organic molecules? How to prepare it?
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Check this out:
DOI: 10.4018/978-1-4666-0122-2.ch017, Physiological Systems Modeling, Simulation, and Control.
Commonest to mimic is the Phosphate Buffer Saline at pH7.4, you will need to prepare and preparation method is available on net, you will need to search or contact any biochemist working at your place. Although your PBS may not be exactly good media for the inversion reaction, and the attached link may lead you to design a better system. Thank you.
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I have prepared some nanoparticles encapsulating curcumin and I need to do a release test at pH 7.4 with these formulations to prove the sustained release of curcumin. However, as far as I know, curcumin is susceptible to quick degradation at this pH so this test seems unfeasible. I have found a lot of papers with release test of curcumin under sink condition at pH 7.4 but none of them mentioned the possible degradation of curcumin during the test. I don’t know if they intentionally or unintentionally ignore this problem. Does anyone have experience on this test or know some articles with reliable method for this? Thank you in advance.
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Dear Van Le , in the case of investigating the drug release process, the only thing matters is the trend of concentration variations over a period of time not the exact concentration. Since the effect of decomposition at nearly neutral pHs on the concentration of curcumine is rather insignificant, it does not considerably affect the trend. However, it is feasible to carry out a more accurate analysis by taking the kinetics of decomposition into account and compensating its effect. More explicitly, you should find the decomposition rate equation of curcumine by which you can make the proper correction for the measured concentration at each particular time. Attached you can find an article concerning the decomposition kinetics of curcumin at different pH values which can be helpful in this regard.
Best,
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Provided that native protein contains more hydrophobic amino acids.
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I think the answer is yes, because changing the pH affects whether certain side chains that are exposed to the solvent are protonated or deprotonated. A protonated acidic side chain (Asp, Glu, C-terminus) is more hydrophobic than a deprotonated one. A deprotonated base (His Lys, Arg, N-terminus) is more hydrophobic than a protonated one.
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I'm working on an industrial wastewater mainly composed by DMF and alcohols. I'm treating samples with hydrodynamic cavitation, hydrodynamic cavitation/H2O2 or hydrodynamic cavitation/O3 but at the end of each process the COD value is slightly higher than the wastewater one. I tried to remove excess of H2O2 by heating the samples at 90°C or adjusting pH to 10-11 and then heating at 45°C because of its interference, but also other samples have same problem Hannah Instrument COD kits are used to determine COD values.
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Hi. Sources of COD in stormwater are varied. However, soluble organic compounds are most likely to contribute to escalated COD concentrations. Residual food waste from bottles and cans, antifreeze, emulsified oils are all high in COD and are common sources of COD for industrial stormwater.
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What are the recommended buffers and ionic strengths for pH 10 , pH 12, pH 14, to study protein secondary structure in circular dichroism ?
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Adron's recommendations are extremely useful for protein crystallization. However, most of the Good Buffers will interfere significantly in circular dichroism studies. Perhaps a buffer that could be used within the high pH range is borate. If salt is required, you may use NaF instead of NaCl, particularly in wavelengths lower than 200 nm.
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The reason why I don’t want to use NaOH to adjust its pH value is because the gold solution (HAuCl4) starts to precipitate when adjusted to pH>7.
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Dear Chen-Wei Lai many thanks for asking this very interesting technical question. To my knowledge, adjusting the pH value of tetrachloroauric acid (HAuCl4) with NaOH to ca. 9-10 in aqueous solution should present no problem. This has been described for example in the attached Suplementary Information of the article
Plasmonic Giant Quantum Dots: Hybrid Semiconductor-Metal
Nanostructures for Truly Simultaneous Optical Imaging, Photothermal Effect
and Thermometry
(see first paragraph on page 2)
An obvious alternative would be to use an aqueous solution of ammonia (NH3) to adjust the pH value. However, I would strongly suggest to stay away from using ammonia in this case. Addition of ammonia to a solution of HAuCl4 could lead to the formation (precipitation) of so-called "fulminating gold", which is highly explosive. For more information about fulminating gold please have a look at the respective Wikipedia entry.
Good luck with your research and best wishes!
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Looking forward to comments and suggestions to the following:
It is quite common to use chlorine-based (sodium hypochlorite) Open Plant Cleaners (OPC) foam cleaners in slaughter houses. Using such cleaners can however lead to high levels of AOX in waste waters.
To adjust the final pH of the waste water carbon dioxide (CO2) is used instead of using standard acids, e.g. sulfuric or hydrochloric acid.
The CO2 is injected via a nozzle. The question is whether there is such a significant drop in the pH value at this point and whether this promotes the formation of AOX due to the higher reactivity.
Are there any extra ways we can reduce the AOX levels, considering high AOX levels cannot not be avoided when using hypochlorite-based cleaners?
Looking to response!
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A more economically attractive option for treatment of the organic halides is through utilization of biological agents. Recently, bacteria (Ancylobacter aquaticus), fungi (Phanerochaete chrysosporium and Coiriolus versicolor), or synthetic enzymes have been used in the degradation of chlorinated organic compounds. The microorganisms degrade halocompounds using either aerobic or anaerobic processes. The mechanisms of degradation include utilization of the compound as carbon source for energy, cometabolite, or as an electron acceptor. Note that enzymatic or microbial action could be regulated through feedback inhibition-the final product in the series inhibits a reaction in the process. https://en.m.wikipedia.org/wiki/Adsorbable_organic_halides
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Part of my thesis is to measure the pH of aqueous extract of chaga, aw and dry matter of powder chaga, TCP (g GAE / kg) and antioxidant capacity (DPPH in %) in aqueous and methanol extract. I need to compare my values with others, but I can't find relevant sources. Please help.
We made aqueous extracts of chaga with a water temperature of 20, 50 and 100 ° C. The extraction time was 5 minutes.
Any results will help me.
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Hi,
For a research project, I want to measure enzyme activity during the process. Is it possible to measure this with a pH meter? In some results I already saw a pH change, however for me it's not clear what the enzymes do on the pH.
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you may have pH changes by enzyme’s action.
The correct way to measure it is by using a galvanic cell as probe. Just a pH meter may not be possible due to huge necessary dilution, that has the potential to change the overall system behavior.
Best regards
WNM
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I have investigated that synthesis is done in a basic medium to obtain three-dimensional particles; but I have read that in some media they say that the particle size increases if the pH increases, in other places the particle size decreases if the pH increases. Could someone help me or explain this?
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As all you said, long-chain nanoparticles are synthesized at acid pH, while larger-sized nanoparticles can be made at basic pH.
My question was not formulated correctly, what happened is that seeing different works where you want to see the effect of basic pH (constant concentrations of the reagents), some concluded that at higher pH the particle size increases, while that others concluded the opposite, that size decreased if the pH was increased.
Si-Han Wu et al. in their work "Synthesis of mesoporous silica nanoparticles", they provide a graph of how pH (both acidic and basic) affects the condensation rate of silica. From the graph it can be seen that the speed of basic pH is much greater than that of acidic and neutral pH. But at basic pH, you find a maximum speed at around pH 8, and then it goes down again.
This is why I was confused.
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I have observed this in case of both Goat serum albumin and Bovine serum albumin addition to HBSS where the pH of the solution reduced from 7.4-7.6 to 7.2-7.3. Now, looking for the reason.
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Im sorry. I didn't get you.
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why in research papers people are always expressing the acidity of crude oil by total acid number and total base number instead of measuring the pH of the crude oil ?
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because it is more convenient and more indicative
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What will be the products when vitamin C reacts with hydroxyl free-radicals (OH.) at various pH buffers (pH 3, 4, 5, 6, 7, 8, 9, 10, 11, 13). The buffers of pH 3-7 contains citric acid (C6H8O7) and disodium hydrogen phosphate (Na2HPHO4), pH 8 contains disodium hydrogen phosphate (Na2HPHO4) and sodium dihydrogen phosphate (NaH2PHO4), pH 9.8 and 11 contains sodium hydroxide (NaOH) and sodium bicarbonate (NaHCO3), and pH 13 contains potassium chloride (KCl) and sodium hydroxide (NaOH).
Thanks in advance for the expert opinions.
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Vitamin C or ascorbic acid (AsA) is a naturally occurring organic compound with antioxidant properties, found in both animals and plants. It functions as a redox buffer which can reduce, and thereby neutralize, reactive oxygen species. It is a cofactor for enzymes involved in regulating photosynthesis, hormone biosynthesis, and regenerating other antioxidants; which also regulates cell division and growth, is involved in signal transduction, and has roles in several physiological processes, such as immune stimulation, synthesis of collagen, hormones, neurotransmitters, and iron absorption, has also roles in detoxifying the body of heavy metals. Severe deficiency of vitamin C causes scurvy, whereas limited vitamin C intake causes symptoms, such as increased susceptibility to infections, loosening of teeth, dryness of the mouth and eyes, loss of hair, dry itchy skin, fatigue, and insomnia. In contrast, vitamin C can also act as a prooxidant, especially in the presence of transition metals, such as iron and copper, starting different hazardous radical reactions. Vitamin C can both act as a strong, efficient, and cheap antioxidant agent and, at the same time, behave as a radical promoter. Further investigations are needed to illuminate the dual roles of vitamin C
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How to determine precipitation during adsorption of heavy metal ions
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You must calculate the precipitation ph from ks of pbOH2 and concentration of pb2 +
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I am purifying a recombinant protein in E.coli, with an expected molecular weight of 17 kDa and a PI of 4.6. When I put my protein sample on gel, I see a band appearing around 30kDa, so quite big but this is not the mayor issue here (although input is always welcome): This 30 kDa band is visible when I run my SDS-page with Mini-PROTEAN® Tris/Tricine gel (4-20%). When i run the same sample on a Criterion XT gel with Bis-Tris-HcL MOPS buffer system, i see this band arround 24 kDa. Any idea why this could be? I also have another protein with similar PI (and expected size of 40kDa) that shows a band around 50kDa in the Tris-Glycine but around 40 in the Bis-Tris MOPS.
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Nah, termini are almost always disordered, the rest seems fine. Also, I believe the charge would explain only why it doesn't run as it supposed to (17 kDa), not why it runs differently on 2 different gels. Other reasons why it doesn't run at 17 could be some PTM, type of buffer used, whether protein is in detergent, generally shape of a protein in case it doesn't get totally denatured and so on. Anyway, I've seen different markers giving different masses before so I wouldn't be surprised if that was the case. Unless your lab used both of these markers for a long time and they were always fine.
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I have been struggling trying to create a standard curve with cisplatin. I have been using the method attached in the article below.
Here is the method I have been following...
1. 10 mg cisplatin HCl was dissolved in 5 mM phosphate buffer pH=6.8 in a 100 mL standard volumetric flask and diluted using phosphate buffer to make 100 ug/ml cisplatin stock solution.
2. 10 ug/ml cisplatin solution was made by diluting 10 mL of stock solution in 100 mL volumetric flask using phosphate buffer.
3. from 10 ug/ml cisplatin solution, 0.4, 0.6, 0.8, 1.0, 1.2, 1.4 mL aliquots were withdrawn and placed into 10 mL standard volumetric flask.
4. 1 mL of 1.4 mg/ml OPDA solution (made in DMF pH=6.4 adjusted with 0.1 N HCl) was added into each solution.
5. 2 mL of phosphate buffer was added to each solution
6. the solutions were heated on a hot plate at 100 C for 10 minutes
7. solutions were cooled to room temperature
8. solutions were diluted with DMF
9. absorbance was measured at 706 nm using DMF as blank (750 baseline correction).
I am really not sure what I am doing wrong. I believe I am following the protocol correctly but when I measure the absorbances they are all reading low and relatively the same value. What might I be doing wrong?
My possible guesses....
1. cisplatin stock solution is not fully dissolved and should be heated?
2. the standards should be heated longer than 10 mins.
3. using a hot plate is incorrect?
4. temperature is actually lower than expected because I am heating all the standards together at one time?
thank you in advance for your help and suggestions
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If you try 0.15 M KCl, it might help your solution to be stable for a longer time.
Why adjust the pH of OPDA before mixing? Why not after mixing?
The solutions were diluted with DMF or acidified DMF?
Why adjust pH with HCl? Why not use weak acid not to miss the pH value?
Do you have a pH meter for organic solvents? Why not make easier with addition of some water to the organic solvent as I have performed in my study?
I would very much like to hear your response if you could increase the absorbances.
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We have a Hepes that is 1 M. We require 5-10 mM Hepes for balance pH in cell culture medium. What should we be added amount of water to prepare for the level of 5-10 mM Hepes?
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Your final concentration will be 5-10 mM of HEPES in your culture medium?
You can use 1M HEPES and add it into your culture medium (better if HEPES is sterilized before), for this use the formula : (1M x vol. needed (mL) = 0,005 or 0,01 M x culture medium volume (mL). So the volume needed is : 0,005 or 0,01 M x culture medium volume
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I'm preparing enzyme-responsive polymeric nanosystems and according to the manufacturer's information, the enzyme is in
-» "50 mM sodium acetate buffer, 1 mM EDTA, pH 5.0.";
-»"≥10 units/mg protein" and
-» unit definition "One unit is defined as the amount of enzyme that will hydrolyze 1.0 µmol of compound x per min at 40°C, using 100 mM Na+/K+ pH 6.0, with 1.33 mM EDTA and 2 mM DTT as the activation buffer."
The flask has 50 micrograms of enzyme.
Concentration: 0.451 mg/mL.
416.0 U/mgP
I wanted to prepare 0.5 UN/ mL solution.
Thanks very much
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@Marco: you are definitly right! I made a slight calculation error... ;)
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I am looking for a buffer system maintaining a pH range of 6.1 – 6.7 which does not interact with the metabolism of yeast cells included in the reaction solution (positive and negative interaction).
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I have used maleic acid and Tris in order to get a Tris/maleate solution to buffer optimally the pH range 6.2-6.8. To my knowledge maleate is not used in the yeast metabolism since it cannot interconvert to fumarate or succinate spontaneously as it does happen in some industrial and chemical procedures.
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I'm preparing modified simulated body fluid for bioactivity tests,, but the resulting solution has always pH of 6.11 to 6.17! which is too low obviously!
and when I add 1 M NaOH to adjust the pH as mentioned in Ayako Oyane paper (2003), the solution start to have very pale yellow color with precipitations in it, although before adding NaOH its like a water clear without any precipitations or color
How can I adjust the pH without changing the color and clarity of the liquid??? 
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The original SBF solution, which can be named c-SBF, is a TRIS-HCl pH-buffered solution (pH = 7.40 at 37 ºC) that can be prepared as indicated at Table 5.1 (p. 206) of the following reference:
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I need to determine the volume required of sulfuric acid to be added to my process to decrease the pH of my e. coli fermentation solution from 7 to 5. The initial volume of solution is 12,000L and pH of sulfuric acid used is 0.3.
To summarise:
- Initial pH = 7
- Initial volume = 12,000L
- Sulfuric acid pH = 0.3
- Volume of Sulfuric Acid = ?
- Desired pH = 5
- Final volume = 12,000 + V(H2SO4)
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Carlos answer is correct: it depends what else is present.
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Hi I am trying to create a bioassay that relies on magnetite nanoparticle (100nm) having a shell material that has NO peroxidase activity. I am trying to coat the particle so that the outside environment does not contact the magnetite core. The shell material must be stable at pH 4 and not allow Fe ions to leak out. Therefore, silica is not an option. Is there any material that fits this purpose?
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Sushilkumar A. Jadhav I have read several of these papers and not any of them address the stability of the silica, only measuring drug release rates. If you are unable to provide any kind of published evidence of silica's stability, then I thank you for the contributions you have already made.
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Dear all,
i a question. I have the need to measure soluble collagen from colon mouse tissue but i do not have freezing colon samples but only the protein extract for wester blot analysis (- Hepes pH 7,9 -EDTA pH 8,0 -KCl -Nonidet; DTT, PMSF, Aprotinin , Leupeptin, Na3VO4). Do you think that I can quantified collagen in this protein extracxt?
thank you all
bye
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Collagen can be determined in any kind of protein extract. However there are two aspects to be taken into account. First, if the other components of the solution are interfering with the specific procedure of collagen determination; second, if you like to evaluate just the total amount of collagen in your extract or you are looking for a specific type of "soluble collagen" : neutral salt soluble collagen, acid soluble collagen, pepsin soluble collagen and so on.
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#bioethanol #fermentation #yeast #pH
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Does the pH always decrease as the phosphorus concentration increases? Has anything been observed to increase pH as phosphorus increases?
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Are you talking about soil..??..
Usually , as the soil pH goes down with leaching of divalent bases under the influence of rainfall as it happens in case of Alfisols/Ultisols/Oxisols , the phosphorous starts getting precipitated with aluminium and toxic level of iron to form aluminium -and ferrous phosphates, respectively, far less available to plants . On the other as well, as the soil pH increases , the same phosphorous gets precipitated predominantly as calcium phosphates , this is again far less available to plants . If a soil is waterlogged and soil pH is buffered around neutrality , here phosphorous would be in maximum quantum , all three forms viz., Fe-P, Al-P and Ca-P , apart from occluded form of P, find their way collectively to be available to plants.
It happens often in sodic /alkali soils with dominance of exchangeable sodium , the formation of sodium phosphates turns phosphorous on a higher side in available form, but high ESP coupled with EC and pH , collectively debar plants in a position to absorb this form of phosphorous, so its a complex chemistry of phosphorous.
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The pH of Fe(II)(Cysteine)2 was 7 in my experiment, and after 8% O2 injection, pH was increased to 8.3
Could you teach me why this phenomenon is occured?
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Dear Kim Hyun Woo many thanks for your interesting technical question. It is certainly possible that the reduction of O2 produced some OH ions which caused the increase in the pH of your reaction mixture. For more general information about this process please go through the following article:
Oxygen Reduction Reaction
This paper is freely available as puublic full text.
For some more detailed information about the redox chemistry of Fe(II) cysteine complexes please also have a look at the following useful Rg link:
Redox interactions between Fe and cysteine: Spectroscopic studies and multiplet calculations
Good luck with your research! 👍
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How can I calculate lime requirement for increasing soil pH without Lab determine? or which methods are faster and easier than woodruff buffer solution?
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The quickest way is to titrate with a strong base such as NaOH or KOH with a pH meter or mixed indicator to measure the change in pH. You need a background electrolyte such as 10 M CaCl2 or 1 M KCl and to target a pH about 0.5 units above the target, so that over the year following liming, the field pH will stabilise close to the target. The target in the surface 15 cm should be above 6 (in CaCl2) if you want the liming to ameliorate the subsoil pH
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I ordered Type 1 collagen from sigma (C9879) and followed the instructions to dissolve in 50mM TES buffer with .36mM CaCl2. I am currently trying 2.5mg/ml and it is hardly going into solution.
I am worried about making the solution too dilute as the pH can affect the overall pH of my gels once solubilized.
Does anyone have experience making collagen zymography gels? If so any input would be greatly appreciated!
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Hi Tyler Panzner Did you find a solution to dissolve collagen I in the gels? I am interested because I have the same issue.
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Hello,
Recently I've been looking for a strict guidelines considering the stability of chromatographic mobile phases. Found none, only some hints, good practice clues or SOP's from different labs all based on "scientific judgment". It is great for RnD, but not enough for GMP/ISO.
I bet many people here already dig this topic inside out. Can anyone direct me towards clear guidelines or possibly share the methods of testing the stability of the different mobile phases (besides pH checking) that she/he uses?
Any "hard facts" would be greatly appreciated especially for those working with routine and GMP analyses, and before audit :)
Cheers!
Natalia
📷
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Best wishes on this project but it is dependent on all the variables in an LC column that affect the material passing through the column. Best wishes, David Booth
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pH can influence the efficiency for pesticides. We also know that hardness of the water can influence the availability of nutrients in fertigation systems.
How do both of these parameters influence the effect on foliar application of fertilizers.
There is one interesting article on effect of pH on cotton for foliar.
Do people know more articles or have experience with the effect on efficiency or phytotoxicity?
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I have PEG conjugated antibody in pH 10 borate buffer. I have to run SDS PAGE to determine MW. In this case prior running the gel do I need to do buffer change of the sample? Like borate buffer to PBS?
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Agree with Engelberth. If your borate buffer is not of a high concentration, you could use the smallest possible volume of your sample and mix it with a larger volume of highly concentrated SDS-sample buffer, to achieve an adequate final pH and run the sample successfully.
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Need a detailed answer
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Thanks
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I am trying to understand the cause of cell lysis (specifically red cells) in ultra-low pH ranges (between 1 and 2) but I am struggling to find papers/research below pH 3. Is there an obvious reason for this? Many thanks, Niamh.
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What do you want the lysate for? Proteins, for example, will denature at this pH, and probably even coagulate. That can even be intended, for example, to separate soluble amino acids from insoluble proteins by precipitation with sulphosalicylic or trichloroacetic acid.
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I am focusing on researches dealing with evaluation of the soil biodiversity associated with tea orchards, in which the pH of soil is very low ranging between 3 and 4. Regarding this, any opinions can give us suggestions in improving the quality of these acid soils of tea gardens by applying biochar in order not to lose its biodiversity.
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An interesting question . Tea is globally grown on acidic soils representing Alfisols/Ultisols/Oxisols predominantly with Entisols/Inceptisols to a lesser extent . This is one crop , we anticipate huge multiple benefits due to biochar intervention , let it be any range of acidic cultivated soils , right from improvement in soil health to disease management , but need a long term study.
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Soil phosphorus (available P) extraction method!
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Dear Frank Omoregie, thank you very much for your response. Do you the experience working on acidic soils with this extraction? Did you see the literature in the acidic areas of the world with this extraction? I could refer you to Pedro A. Sanchez (2019). Properties and Management of Soils
in the Tropics, page 406, Table 14.9 states that P-Olsen is used in a wide range of pH! You can get it on: www.cambridge.org/9781107176058
DOI: 10.1017/9781316809785
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I have to perform Western Blot on FFPE tissue and the first part is the extraction.
First I did deparaffination, then I added the extraction buffer (20 mM Tris-HCl pH 8, 2% SDS) and I incubated for 20 minutes at 99°C and for 2h at 80°C.
This is the result with and without pellet. Can I understand by eye if the proteins are in here? Is there some clue that makes me understand that the lysis didn't occur correctly? Or do I have to wait until staining with ponceau S?
Someone that did something similar could tell me if this is the right apperance?
Thanks for your help
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It is very difficult to detect proteins inside your container with the naked eye.Because depending on the method, the concentration of proteins varies.
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Hello,
working my very first time with hexachloro-cyclotriphosphazene, I was very careful because hexachloro-cyclotriphosphazene is known to react with water very vigorously.
However: Nothing happend in my experiment. Not in water, and not @ high or low pH or @ elevated temperatures.
Can anybody explain this?
Thank you in advance!
Sincerely
Bernd
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Dear Nagalakshmi,
thank you for your answer! However, I do not agree.
Think about all the other polymer-analoguous reactions of high molecular weight in solutions.
Hexachloro cyclotriphosphazene has only M = 347,66 g/mol.
So, the hydrolysis of the Cl atoms should take place, normally.
Best regards
Bernd
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Using NaOH and NaHCO3
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Add 29.1 ml of 0.1 molar NaOH to 50 ml 0.1 molar potassium dihydrogen phosphate. Alternatively : Dissolve 1.20g of sodium dihydrogen phosphate and 0.885g of disidium hydrogen phosphate in 1 liter volume distilled water.
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It's a buffer for protein extraction from FFPE tissue, but it's not actually important for the answer. I just want to understand what to do exactly
I want to prepare 100 mL of this buffer:
2% SDS
20 mM Tris-HCl (pH 8)
I took 0,24 g of Tris and put it into the beaker, I added 0,1 mL of HCl, added 2 g of SDS and filled with dH₂O until I reached 100 mL
Now, my doubts are:
- Should I at first prepare 20 mM Tris-HCl and only after that add it to the 2 g of SDS until I reach the desired volume?
- Some people told me that actually "2% SDS" means that I have to first prepare a solution with 2% SDS and distilled water, and only after add it to a 20 mM Tris-HCl solution. If it's so, how can I understand how much volume of Tris-HCl and 2% SDS should I put in my solution to reach 100 mL?
Thanks for your help
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Considering the wide range of acceptable pH values, and the fact that the pKa of Tris is in the center of the range, if your calculation of the amount of HCl is correct, then it should be OK.
You did not say what the concentration of the HCl solution was. Concentrated HCl is about 11 M, so 0.1 ml contains about 1.1 millimoles.
100 ml of 20 mM Tris contains 2 millimoles.
The pKa of Tris is 8.1.
Based on the Henderson-Hasselbach equation, that should result in a pH of about 8.
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Current I am using calcium hydroxide but at higher pH it make gel type material
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Waste nickel catalyst after acid leach, ammonium sulfate and sodium sulphate are added into leachate, when ammonia-alum crystal separate out and you will get nickel sulfate solution
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I'm reading a research paper that stated the pH value of the decreased due to the production of carbonic acid and other organic acids. Therefore, I want to know what types of carbonic acid and organic were produced that caused the pH to drop after the fermentation.
Thanks!
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Dear Aa Amir thank you for your interesting technical question. However, in order to give you a qualified answer you should perhaps be a bit more specific and let us know what material is fermented in your process.
When we talk of carbonic acid, it is often written as "H2CO3". However, this compound does not exist as a stable molecule. H2CO3 just means carbon dioxide (CO2) dissolved in water. Thus when we talk about "carbonic acid" being formed during a fermentation process, it's just the CO2 bubbling out of the reaction system.
In addition to CO2, various organic acids can be formed during fermentation processes. For example, lactic acid is a typical organic acid which is produced in large quantities by fermentation of carbohydrates. In this context please have a look at the following useful research article:
In-situ recovery of carboxylic acids from fermentation broths through membrane supported reactive extraction using membrane modules with improved stability
This article is freely available as pubic full text.
Yet another organic acid which can be produced on a large scale through fermentation is succinic acid. For more information about this please see the following relevant article which can also be downloaded as public full text:
Succinic Acid: Technology Development and Commercialization
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The amino group has a pKa of ca. 6,5
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It depends on other considerations like temperatures quantities and range of PH.
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For protein collection I used Ripa buffer (50 mM Tris-HCl, pH 8.0, 150 mM NaCl, 1% NP-40, 0.5% Sodium deoxycholate, 0.1% SDS, ) and put into ice immediately after collection. After 30 min incubated, centrifuge 12,000 rpm and collect supernatant and quantify protein. 15 ul to 20 ul protein loaded where protein concentration 40 ug/mL. I used cell and usually culture in 10 cm petri dish plate.
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Hey, I think your question has been answered but for BSA I would try 3 percent first and then try to increase the concentration if that does not work well.
Like others have mentioned, when you are making 5% milk make sure its mixed well and does not have any undissolved particles.
Also try by increasing the washing steps in between.
Good luck!
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Dear all, I am studying microbiology for mater degree course.
So now I am performing MTT assay, and have some questions.
I use HT-29 cell with 5 x 10^4 seeding level and have 3 samples with 4 concentration for treatment group, use DW for control. I would call samples A, B, C for understanding.
I treated all samples for 18 h, and treated MTT solution for 2 h, using DMSO as final solvent and reading O.D at 540nm wavelength. MTT assay performed 4 times.
sample A and C showed 80~120% cell viability in every concentration.
BUT only B showed overflow in almost every well or 600~800% cell viability at lowest concentration in all test.
I checked pH of sample solutions, B and C have pH level between 4.8-5.0, A was about pH 6.3
Does anybody have similar experience? Please give me some advice.
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thank you for your advice.
B is kind of fermented milk powder, spray dried.
but other similar powder(C) doesn't have any problems.
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Hello,
During the synthesis of nanoparticles, many at times a particular pH value is optimum for that process.
I am confused as to whether the pH needs to be adjusted during the reaction while mixing the precursors, or after mixing the precursors (followed by continued stirring for a certain period of time).
Does it depend on the reaction or is there a preferred way?
I am asking this as I have found both of the above mentioned approaches in papers.
For example for the synthesis of covellite copper sulide (CuS) nanoparticles:
  1. https://linkinghub.elsevier.com/retrieve/pii/S2352507X15300159
  2. https://linkinghub.elsevier.com/retrieve/pii/S0254058419308272
Thank you
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Dear all, if the pH has an additional role besides reduction, for exemple in the solubilization of precursors and surfactant/caping agents performance, then it should be adjusted first. Otherwise it is optional. My Regards
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According to some research, the pH of Tris-HCl depends on temperature. I have also checked that if I prepare Tris-HCl at room temperature, then put them at 4℃. As a result, the pH improves from 7.5 to 8.1. And I hope to make the protein stay at a low temperature which can ensure the structure and biological activity. So, maybe storing the stock of Tris-HCl at 4℃ is better. But, If I want to use the protein to try growing crystals, usually, the crystal plate was put at room temperature for two weeks first. I just worry about if the changing of buffer pH would have a bad effect on the crystals. Except putting the crystal plate at a low temperature first, is there any good method to solve this problem?
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I would not say "according to some research"...
Different buffers show different temperature dependency or temperature sensitivity. The key point is the buffer ionization enthalpy, and different buffers have very different ionization enthalpies. For example, phosphate has a very low ionization enthalpy (around 1 kcal/mol), but Tris has one of the largest ionization enthalpies (around 11 kcal/mol) among the usual buffers.
According to the van't Hoff equation: δlnKa/δT = ΔHa/RT2
where Ka is the acid dissociation constant (ionization equilibrium constant), ΔHa is the ionization enthalpy, and T is the absolute temperature
If ΔHa is positive, then, a decrease in temperature would cause a decrease in Ka. If Ka (dissociation constant for protons) decreases, the proton affinity of the buffer increases and the concentration of free protons decreases, resulting in an increased pH.
There are tables with the δpKa/δT factors (temperature sensitivity factor of the buffer) available: δpKa/δT = δpH/δT = -ΔHa/2.303RT2.
You can prepare the buffer solution and adjust the pH at a temperature close to the experimental temperature.
However, as Pengcheng Wei said, when setting up crystallization samples the buffer contained in the protein stock solution will contribute very little to the final pH.
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I am doing research in land suitability evaluation for Ginger production and I need to assign the weights for the analysis factors. I need experts decision about the importance of the factors affecting ginger growth. Can you help order the factors from the most important to the least important?
For example, if you think that pH is more important than OM for Ginger and more affecting the wheat growth you write in your answer like this pH > OM. Or Using satty scale (0-9) to give relative importance of each factors.
The factors or the parameters are 9:
pH, Slope, Soil depth, texture , Organic matter, N, P, K.
Please order using “>” simple. or satty scale of preference
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Ginger being a tropical plant is best in warm and sunny climates. Deep well drained soil loam high in organic matter suits best. pH range of 6-6.5 is better at a minimum temperature of 15.5 degree C (59.9 degree F). Partial shade would be ideal. Heavy manure and fertilizer would promote better yield. You can also use ginger buds as well.
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I have established linearity for my sample in HPLC, still the LOD is not to the required mark(at the present the method can detect 200ng/ml). But I want the method to be sensitive enough to measure 25-50ng/ml. I used a method from the paper but without adjusting pH. Will pH adjustment increase the sensitivity?
What are the general ways to increase the LOD for the method you have established?
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Larger injection volume (more mass on the column), more sensitive wavelength (generally lower wavelength), more sensitive detector (MS in lieu of PDA/DAD), smaller particle size, shorter column (uHPLC in lieu of regular HPLC).
Yes, pH buffering will sharpen the peak (prevents the formation of ionic forms), and even increase the peak size!
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41.0 mL of 0.0150 M hydrochloric acid, 130 mL of 0.0650 M hydroiodic acid and 55 mL of 0.00680 M sulfuric acid are pipetted into a 250 mL volumetric flask, which is then filled up to the mark with distilled water. What is the pH of the final solution?
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