Development and evaluation of a GC/FID method for the analysis of free amino acids in quince fruit and jam

A GC/FID methodology for determination of twenty-one free amino acids in quince fruit (pulp and peel) and jam is described. The sample preparation was simple, involving a SCX Solid-Phase Extraction (SPE) purification step and a fast derivatization with ethyl chloroformate for gas chromatographic analysis. The chromatographic separation was achieved using a CP-Sil 19 CB wcot fused-silica capillary column. Under the chosen conditions, with temperature and pressure programming, this capillary column was able to separate all the amino acids not only in a short time but also with good separation. The GC/FID procedure is rapid, sensitive, reproducible and accurate. The detection limit values for amino acids were low, between 0.004 and 0.115 microg/mL, and the method was precise. As a general rule, the recovery values were high. Due to its rapidity and low cost, this technique can be useful in the quality control of quince products.