Simultaneous Determination of γ‐Aminobutyric Acid and Glutamate in Human Gastric Mucosa by HPLC, as their Phenylisothiocyanate Derivatives

Abstract

A high performance liquid chromatographic (HPLC) method was developed for the simultaneous determination of γ‐aminobutyric acid (GABA) and glutamate (Glu) in human gastric mucosa. After gastric mucosa tissues were dried under liquid nitrogen, ground, and ultrafiltered, the amino acids in these tissues were derivatized with phenylisothiocyanate. The phenythiocyanates of amino acids (PTC‐amino acid) were then separated on Pico·Tag™ column, eluted with gradient mobile phases, and detected at a wavelength of 254 nm. The linear responses observed were 0.125–6.25 µM for GABA and 0.025–2.5 mM for Glu with the correlation coefficients of 0.9988 and 0.9998, respectively. The detection limits for GABA was 0.05 µM. The recoveries for GABA and Glu determinations were in the ranges of 90.4–104% and 88.1–105.5%, respectively. The intra‐ and inter‐day RSDs were less than 10%. The method was sensitive, specific, and accurate for clinical application of GABA and Glu in human gastric mucosa tissues. It was found that GABA and Glu concentrations in gastric cancer tissues were higher than those in normal gastric mucosa tissues.

Keywords:

• γ‐Aminobutyric acid
• Glutamate
• HPLC
• Gastric mucosa