Detection of free amino acids in plant material using gas chromatography method

Matas Gaivenis final thesis for master‘s degree/ scientific supervisor prof. dr. Liudas ivanauskas; Lithuanian University Of Health Sciences, Faculty of Pharmacy, department of Analytical and Toxicological Chemistry. – Kaunas. Aim of the work: detect and choose optimal condition for detection of amino acids in plant material. Tasks of work: perform analysis of scientific literature and evaluate possible derivatisation agent for amino acid detection; choose and test possible derivatisation agent; optimize detivatization and extraction conditions; compare free amino acids amounts in different plant material. Object and methods: Buckwheat seeds grown under organic and conventional farming conditions, croc tubers and Cannabis sativa seeds. Assay analysis performed by gas chromatography coupled with mass spectometer. Conclusions: 1. The best result was achieved when (N-methylN(tertbutyldimethylsilyl)trifluoroacetamide) MTBSTFA was used. 2. Optimal conditions for extraction are 1g of plant material, extraction is cariedwith methanol. Plant material is poured with 10 ml methanol, ultrasonicated, and left to extract for 24 hours. 3. Optimal conditions for derivatization are extract is heated with derivatizator and acetonithrile in glycerol at 100OC for 2,5 hours 4. Biggest total amino acid quantity was found in cannabis seeds (197,51 mkg/ml) and lowest on ecologicaly grown buckwheatseed (12,2 mkg/ml). Results gotten comparing buckwheat seeds showed that 1,7 times bigger total amound of amino acids where in conventionaly cultivated buchwheat seeds