method development and pKa value

Waters 2707 HPLC autosampler problem?

I am using a 2707 waters HPLC device. When I try to inject a sample, it says missing plate or rack. I changed the needle and calibrated its position but I still get the same problem. I even get...

02 March 2021 1,408 1 View

How optimize the Size Exclusion Chromatography?

Hello! I'll do a size exclusion chromatography, but I only have an open column, and I'll perform the peptide extraction from yeast, using buffer lysis (sodium phosphate 50 mM/NaCl 30 mM/DNAse and...

01 March 2021 2,215 2 View

Precipitate after adding laemmli buffer to protein solution containing Potassium Acetate?

Hi, I am running a size exclusion chromatography experiment with a buffer containing Potassium Acetate as a salt. I analyse these fractions through SDS-PAGE. After boiling my SEC fractions in...

01 March 2021 2,622 3 View

Any research papers for extraction of nutrient deprivation on macroalgae? Analysed by HPLC-UV and GC/MS. Possibly from macroalgae genus Rhizoclonium?

I am doing my thesis on the nutrient deprivation on the macroalgae Rhizoclonium sp. I will be analysing the levels over a period of roughly 5 days by HPLC-UV and GC/MS. I will be using seawater as...

28 February 2021 6,477 1 View

Do you kow of any database containing data on retention time, log P and polarizability for a large number of molecules?

Hi, I am a chemistry undergraduate doing my dissertation project on HPLC. In my project, I need to predict the HPLC retention time of 20 aromatic molecules, the calibration set. To do this I will...

24 February 2021 2,602 1 View

Any easy method of analyzing vitamin D in foods by HPLC?

Looking for method of extracting and analyzing vitamin D in foods by HPLC

24 February 2021 7,524 7 View

What HPLC Marker(s) should be used to detect anthocyanins in a sample?

What HPLC Marker(s) or standard is used to detect and quantify anthocyanins such as Delphinidin, Cyanidin in a given sample of plant extract?

23 February 2021 1,832 4 View

HPLC baseline failure (ACN/Water)?

My baseline increases without any explanation, it is only fixed by changing the solution B, will it be the column? Reagents? Bomb? Detector? Solution A: H3PO4 0.01% IN WATER Solution B: H3PO4...

21 February 2021 5,656 3 View

Which vial septa the right one to be used for HPLC?

This is the unanswered question stored very long in my mind and till now I could not find a right answer. Google search educated me that the red surface is the PTFE material compatible to wider...

21 February 2021 546 3 View

What is the stability of 2 3-dihydroxyquinoxaline in acidic water?

I'm developing a UHPLC assay, and the fluorescent product is 2,3-dihydroxyquinoxaline. The reaction to produce this requires hydrochloric acid (about 1.2 M). Will storage in this acidic...

20 February 2021 5,820 4 View

Bhupendra Shrestha

Method development for formulated product or pure drug,it is same. Only we have to ensure that the excipients used in the formulation should not interfere with the method. Regarding pKa, we can determine it by using HPLC. many articles are available regarding this, kindly search in net.

Kizar Ahamed

Hi, thanx for ur reply.

Arvindkumar Sonar

by using Henderson–Hasselbalch equation

Hi,thanx for your reply ,if its possible can u explain with some examples.

Muhammad Adil

How Arvendkumar sonar?