Stability of Catecholamines, Indolamines and Related Metabolites in the Process of Sample Preparation with Ultrasonication and an Analysis by High-Performance Liquid Chromatography

Abstract

For the determination of monoamines and related metabolites in biological samples using high-performance liquid chromatography (HPLC), an ultrasonic treatment procedure was usually utilized in the process of sample preparation. [1][2][3][4][5] During the work of analyzing neuroamines in brain tissue, urine or plasma using HPLC with electrochemical detection (ECD), we prepared these biological samples and noticed the influence of ultrasonication, that is, it badly decreased the recovery of compounds of interest. Until recently, however, the influence of ultrasonication on the stability of catecholamines, indolamines and related metabolites had not been investigated. The optimal ultrasonication condition has not been reported. Therefore, the examination of the ultrasonic effect became necessary. This paper presents the important fact that the ultrasonication process may decompose these monoamines, and describes the influence of ultrasonication on the stability of most major catecholamines, indolamines and related metabolites, and finally applies the optimal conditions to prepare biological samples and to analyze 20 compounds with HPLC-ECD.