Existing problems and ways of their solution in the analysis of amino acid composition

For obtain accurate aminoacids analysis results for peptide samples it is need to pay attention for method of analysis and method of sample preparation. Now some samplpreparation methods are known: acid and basic hydrolysis. In this article the comparison of two methods of aminoacids analysis were observed: pre-column or post-column derivatization. Analysis of lysine in lysine sulphate was studied, results were compared with control samples. For pre-column derivatization o-phthalic anhydride was used, and for post-column derivatization ninhydrin reagent was used. In experimental part advantages of post-column derivatization was shown and more accurate results were obtained. Chromatographic separation, derivatization and detection were carried out on aminoacids analisators Hitachi (Japan) и Sykam (Germany). Samplepreparation methods were observed on valine and threonine analysis using postcolumn derivatization with ninhydrin reagent. The effect of pH adjustment after acid hydrolysis was studied. Basic solution addition best results in comparison with sample evaporation and reconstitution were shown. For final sample analysis optimal methods of analysis and samplepreparation were chosen. Results were compared with results of European Accredited Laboratory.