Problems in EDTA Assay

Discussions about HPLC, CE, TLC, SFC, and other "liquid phase" separation techniques.

2 posts Page 1 of 1
We are analysing EDTA in a pharmaceutical product and we have a peak that appears and grows with time.
The mobile phase is a mixture of 10 mM tetrabutylammonium hydroxide at pH 7.5 and Methanol in a proportion 75 : 25 v/v. The diluent is a solution of copper (II) nitrate 1.6 mM.
The fresh sample shows a peak of EDTA but after 40 minutes appear a new peak.
Is it possible that this peak correspond to a different protonation specie of EDTA? Is it recommended to control the pH of the sample diluent?
Hello. Could you show chromatograms please?
Best regards,
Dmitriy A. Perlow
2 posts Page 1 of 1

Who is online

In total there is 1 user online :: 0 registered, 0 hidden and 1 guest (based on users active over the past 5 minutes)
Most users ever online was 1117 on Mon Jan 31, 2022 2:50 pm

Users browsing this forum: No registered users and 1 guest

Latest Blog Posts from Separation Science

Separation Science offers free learning from the experts covering methods, applications, webinars, eSeminars, videos, tutorials for users of liquid chromatography, gas chromatography, mass spectrometry, sample preparation and related analytical techniques.

Subscribe to our eNewsletter with daily, weekly or monthly updates: Food & Beverage, Environmental, (Bio)Pharmaceutical, Bioclinical, Liquid Chromatography, Gas Chromatography and Mass Spectrometry.

Liquid Chromatography

Gas Chromatography

Mass Spectrometry