Salam to everyone
I know how to prepared the ratio of the mentioned mobile phase . but my question how much the concentration of potassium phosphate buffer which can i mixed ?
thanks
- We normally do not use volume units (V/V) when describing liquids mixed with solids. Please use a more scientifically correct term such as molarity to express the solution concentration.
Enough that it does not precipitate out of solution. Seriously, that is the answer and depending on the grade (quality) of buffer used and pH of the solution (which you did not mention), it may vary.
First, you will prepare a solution of phosphate buffer at a specific molarity in water. Adjust pH, if required. Next you will use that newly prepared buffer solution (a liquid) to mix with another liquid. Here is where things get tricky. The correct way to mix two liquids together is determined by the specific method used (and which should be documented, in detail). For example: You could fill a 1 L graduated cylinder with 970 mls of the buffer solution, then add MeOH to bring the final level to top "To Contain" line. You could also mix together 970 mLs of buffer with 30 mLs of MeOH to make your final solution (and there are other methods too). Can you see how using each method actually results in a solution with different properties? That is why it is critical to document it. In science, we use SOP's to do so. SOP= Standard Operating Procedures.
I have no idea if your question relates to HPLC or not, but here is a link to an article which addresses this concern. The information presented is relative to any question about the preparation of solutions for laboratory use.
I have no idea if your question relates to HPLC or not, but here is a link to an article which addresses this concern. The information presented is relative tomix two liquids together is determined by the specific method used (and which should be documented, in detail). For example: You could fill a graduated
"Part 1, Overlooked HPLC Chromatography Standard Operating Procedures (SOP's); Mobile Phase Preparation"; https://hplctips.blogspot.com/2018/12/part-1-overlooked-hplc-chromatography.html
this why i asked , because the procedure not mention details .
read pls ..
(Determination of Brain Monoamines .
Determination of brain norepinephrine, dopamine and serotonin was carried out using high performance liquid chromatography (HPLC) system, Agilent technologies 1100 series, equipped with a quaternary pump (Quat pump, G131A model). Separation was achieved on ODS-reversed phase column (C18, 25 x 0.46 cm i.d. 5 μm). The mobile phase consisted of potassium phosphate buffer/methanol 97/3 (v/v) and was delivered at a flow rate of 1.5 ml/min. UV detection was performed at 270 nm, and the injection volume was 20 μl. The concentration of both catecholamines and serotonin were determined by external standard method using peak areas. Serial dilutions of standards were injected, and their peak areas were determined. A linear standard curve was constructed by plotting peak areas versus the corresponding concentrations. The concentration in samples was obtained from the curve.)
The authors are responsible for reporting the exact HPLC procedure used. If that is all of the information provided about the HPLC method used (no column brand or type was mentioned and no wavelength bandwidth either), then they failed to do so (all methods must be described in enough detail that they can repeated by someone else) in this regard so their is no way that we can answer the question. HOWEVER, what you copied appears to be an abstract, not a description of the materials and methods used for the entire procedure. Abstracts are short versions and are not expected to include all of the details. For that, you must read the entire paper or article.
Contact the authors and have them provide you with the paper or missing information.
The article should have been rejected for not including enough basic information to understand or reproduce their methods. FAIL.
https://www.nacalai.co.jp/global/cosmosil/pdf/technical_notes1.pdf
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