Optimization of Analytical Method for Amino Acids by Using UFLC-MS/MS

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Research article

Journal of the Korean Society for Environmental Analysis 2012;15(2):107-114.

UFLC-MS/MS를 이용한 아미노산 분석방법 최적화

김지영, 박재선, 남용재, 유은진, 이원석, 최성헌, 한진석, 최종우

국립환경과학원

Abstract

Analytical conditions of amino acids in ground-water by using UFLC-MS/MS(ESI) were optimized for prompt and accurate analysis. Under the Edmen's method, derivatization of amino acids with PITC (phenylisothiocyanate)was performed and chromatographic separation was achieved on ODS (octadodesylsulfonate)-column with 3,400 psi. Within 10 minutes (6 min for MS collection), 21 types of amino acids were simultaneously analyzed by UFLC-MS/MS (ESI) after the selection of qualitative and quantitative ions. This method was precise with percent relative standard deviation of 2.6~13.8 % on 7 replicate analysis and accurate with percent recovery of 81.6~115.3 %. Confidence interval (CI, 3.53~4.25 mg/L). coefficient of determination (r^2, 0.970562 (TRP)~0.999329 (VAL)), limits of detection (0.29(PRO)~1.88(ASN) mg/L (mean. 0.91 mg/L)),and limits of quantification (0.99(PRO)~6.28(ASN) mg/L (mean, 3.03 mg/L)) were obtained and proven to be a reliable method. Derivatives was relatively stable when it occurred for more than three hours under 45oC based on optimum tests. Also, it was notable that m/z 164.15 ion, reagent of derivatization under MS/MS, was identified with phenylalanine in the same time frame, indicating excessive quantity. However, when the quantitative ion was changed from m/z 164.15 to m/z 221.10, relevant result was achieved.

Key Words: amino acids, UFLC-MS/MS, limit of detection, precision and accuracy