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.

amino acids, high-efficiency liquid chromatography, ion-exchange chromatography, capillary electrophoresis, amino acid analysis, acid hydrolysis Amino acids, high-efficiency liquid chromatography, ion-exchange chromatography, capillary electrophoresis, amino acid analysis, acid hydrolysis

1. Fallon A., Booth R.G.F., Bell L.D. Applications of HPLC in Biochemistry. Elsevier Science Publicher B.V. (Biomedical Division), 1987. 314 p.

2. Jakubke H.-D., Eshkite H. Aminoacids, peptides, proteins. Moscow, Mir, 1985. 455 p. (in Russian).

3. Joergensen L., Thestrup H.N. Determination of amino acids in biomass and protein samples by microwave hydrolysis and ion-exchange chromatography. Journal of Chromatography A. 1995. no. 1-2. pp. 421–428.

4. Csapo J., Kiss-Csapo Z., Albert C., Loki K. Hydrolysis of proteins performed at high temperatures and for short times with reduced racemization, in order to determine the enantiomers of D- and L-amino acids. Acta Univ. Sapientiae, Alimentaria. 2008. no. 1. pp. 31–48.

5. Boardman N.K. Ion-Exchange Chromatography. In: Biemann K. et al. Modern Methods of Plant Analysis. Moderne Methoden der Pflanzenanalyse. Berlin, Heidelberg, Springer, 1962. vol. 5. pp. 159–204.

6. Fountoulakis M., Lahm H.-W. Hydrolysis and amino acid composition analysis of proteins. Journal of Chromatography A. 1998. no. 795 (2). pp. 263–275.

7. GOST 13496.21–2015. Korma, kombikorma, kombikormovoe syr'e. Metody opredeleniya lizina i triptofana [State Standard 13496.21–2015. Feeds, mixed feeds and raw material. Methods for determination of lisin and tryptophane]. Moscow, Standardinform, 2016. (in Russian).

8. GOST 33428–2015. Korma, premiksy. Opredelenie soderzhaniya lizina, metionina i treonina [State Standard 33428–2015. Feeds, premixtures. Determination of lysine, methionine and threonine]. Moscow, Standardinform, 2016. (in Russian).

9. Commission Regulation (EC) No. 152/2009 of 27 January 2009 laying down the methods of sampling and analysis for the official control of feed.