SIMULTANEOUS IDENTIFICATION AND DETERMINATION OF TOTAL CONTENT OF AMINOACIDS IN FOOD SUPPLEMENTS - TABLETS BY GAS CHROMATOGRAPHY

The aim of current study is simultaneously identification and determination of total content of 17 aminoacids in food supplements – tablets. Gas chromatographic method with flame ionization detector (GC – FID) was applied. Acid and alkaline (for analysis of Triptophan) hydrolysates were purified by cation – exchange solid – phase extraction, followed by the derivatization of aminoacids with ethylchloroformate. The dissolved in isooctane derivatives were analysed by GC – FID. The identity is proved by the fact, that all data for the retention time (tR) of aminoacids in tablets correspond to the values of tR of the respective aminoacid in reference solution. Reference standard solution contained 200 nmol/l of each of aminoacids: L – Alanine, L – Glycine, L – Valine, L – Leucine, L – Isoleucine, L – Threonine, L – Serine, L – Proline, L – Aspartate, L – Methionine, L – Glutamate, L – Phenylalanine, L – Cystine, L – Lysine, L – Histidine, L – Tyrosine and L – Triptophan. Internal standard Norvaline was used. The best results for the recovery are obtained for the following aminoacids: 1) Amino 1000 tabl.: L – Glycine – 100 %; L – Triptophan – 100 %; L – Threonine – 109.52 %; 2) Amino 2300 tabl.: L – Isoleucine – 96.69 %; L – Proline – 96.81 %; L – Tyrosine – 99.81 %; L – Leucine – 101.67 %; L – Cystine – 102.51 %; L – Triptophan – 106.67 %. The applied GC – FID method is appropriate for quality control with great accuracy for aminoacids L – Cystine, L – Glycine, L – Isoleucine, L – Leucine, L – Proline, L – Threonine, L – Triptophan and L – Tyrosine in food additives – tablets.