Gas Chromatographic Determination of Amino Acids and Polyamines in Human Skin Samples using Trifluoroacetylacetone and Isobutyl Chloroformate as Derivatizing Reagents

Abstract

An analytical method has been developed with improved sensitivity for the determination of amino acids and polyamines after precolumn derivatization with trifluoroacetylacetone and isobutyl chloroformate. 28 compounds comprising of 20 amino acids, five polyamines (1,3 diaminopropane, putrescine, cadverine, spermindine and spermine) and three biogenic compounds (4-aminobutyric acid, histamine and dopamine) separated completely with linear calibration range 1-10 µg/ml and limits of detection 60 -200 ng/ml. The separation was obtained within 11 min from HP-5 (30 m × 0.32 mm id) with column temperature 100°C for 2 min, followed by ramping at the rate of 20°C / min upto 250°C. The nitrogen flow rate was 3.0 ml/min. The method was applied for the analysis of the compounds in human skin samples after acid hydrolysis. The variation in their contents were examined in the affected skin samples from pemphigus vulgaris, psoriasis, leishmaniasis and eczema patients and result were compared with unaffected skin samples from healthy volunteers. The extraction of amino acids and polyamines from samples calculated by standard addition was within 95-102 % with RSDs 1.23-6.75 %.