ECD HPLC

[Gizmo]

I am considering ECD as a new avenue to pursue in our laboratory. The main reason this got on my radar was due to bumping into some of the technical notes offered by a manufacturer as it relates to utilizing ECD results combined with PCA software to effectively identify adulteration of food products such as juices. The independent journal based literature seems to be a little light though.

If anyone has experience with these detectors - Coularray, PAD - working on adulteration problems or singular analysis of specific analytes I would be interested in hearing their insights.

I would be interested in knowing not just about adulteration inquiries utilizing ECD/PCA but also if ECD would be a practical solution for the analysis of singular analytes such as:

Water soluble B vitamins
Amino acids, specifically Taurine
Organic acids - citric, malic, tartaric

I know, I am asking a lot here but other than manufacturer technical papers the information via the google seems a bit light - perhaps there's a reason for that or perhaps ECD could be viable for some or all of these. My knowledge in this area is not very strong obviously and with some fast upcoming decisions to be made I am seeking all the help I can get.

Thanks in advance for any insights.

[mattmullaney]

Hi, Gizmo,

ECD is certainly good for underivatized amino acids (Thermo Dionex app, for example, integrated pulsed amperometry) and some vitamins (D, coQ10, B group, C), and organic acids.

https://www.thermofisher.com/content/da ... 0872-E.pdf

EDIT My goodness, I stand corrected. Organic acid may be determined by ECD as well:

https://www.ncbi.nlm.nih.gov/pubmed/15030193

J Agric Food Chem. 2004 Mar 24;52(6):1440-4. Determination of organic acids by high-performance liquid chromatography with electrochemical detection during wine brewing. By Kotani A, Miyaguchi Y, Tomita E, Takamura K, Kusu F.

Abstract
Voltammetric determination of acids by means of the electrochemical reduction of quinone was applied to high-performance liquid chromatography (HPLC) with electrochemical detection (ED) for determining organic acids in fruit wines. A two-channel HPLC-ED system was fabricated by use of an ion-exclusion column and an electrochemical detector with a glassy carbon working electrode. An aqueous solution of 0.1 mM HClO(4) and ethanol containing 2-methyl-1,4-naphthoquinone served as a mobile phase and reagent solution, respectively. Determination of acetic, citric, lactic, malic, succinic, and tartaric acids was made by measuring the peak areas of the flow signals due to the reduction current of quinone caused by the eluted acids. The peak area was found to be linearly related to the acid amount ranging from 0.1 to 40 nmol per 20 microL injection. The present method was characterized by reproducibility with the simple and rapid procedure without derivatization of analytes. The method was shown as an effective means for following acid contents in fruit juices during fermentation with wine yeast.

[Gizmo]

Thanks Matt - that was a great source of info - I think going in the direction of metabolomics could be a good way for us to approach adulteration issues for the raw materials we use and ECD might be the right module to utilize for that. And it can be used for some of our current and planned singular component analysis as well.

[mattmullaney]

Hi Gizmo,

Glad to be able to help. I think Michael Dong has written about how MS detection has taken over many of the roles of ECD recently...I've done my fair share of ECD work in my career and have liked it well enough.

Integrated Pulsed Amperometry is one main mode of detection--the main reference for this is:

Pulsed Electrochemical Detection in High-Performance Liquid Chromatography
by William R. LaCourse, ISBN: 978-0-471-11914-2, Aug 1997.