GC-MS separation and determination of 20 amino acids in biological samples based on ethyl chloroformate second derivation

Due to the difference in structure and chemical properties of amino acids, it is difficult to determine amino acids with different properties by GC-MS. A method was established for the simultaneous determination of 20 amino acids by using ethyl chloroformate (ECF) as the derivatization reagent and adjusting pH 9-10 in the second derivatization in this study. The results showed that 20 amino acids were well separated and the compounds in the 2-20 μg·mL^-1 concentrations were detected with a good linear response correlation coefficient r² greater than 0.99. The results of precision and system adaptability show that RSD<10%, the average recovery of samples in the 78.3%-109.9%. The results showed that the method was simple and easy to use, and the derivatization method could be carried out in aqueous solution. The derivatization product was stable with wide linear range, thus this method could be used for the determination of a variety of biological samples such as Astragalus mongolicus, mouse urine sample and mouse serum sample.