Highly Sensitive Analysis of Proteins and Metabolites by Metal Tagging Using LC-ICP-MS

Abstract

Sensitive and selective analytical methods are a fundamental requirement in science, including biochemistry. For example, when there are significant differences in the amounts of proteins and metabolites in a biological sample, all of them must be considered for proteomics and metabolomics, even if their contents are very low. Now, the analytical technique with metal tag using liquid chromatography–inductively coupled plasma mass spectrometry (LC-ICP-MS) attracts attention as a highly sensitive method. It is used in inductively coupled plasma mass spectrometry (ICP-MS), which is one of the most sensitive instruments for the detection and determination of organic compounds, proteins, and metabolites. The organic compounds are usually unable to be detected with ICP-MS. Then, they are artificially derivatized by metal tag reagent before detection. The derivatization with metal tag reagents is performed for the purpose of building the bond between the metal and the analytes. The metal of the metal tag is able to select for the easy detection and high sensitivity of ICP-MS. The derivatization is almost never used for inorganic analysis. But, it is a well-known preparation in chromatography. It is able to convert the nature of the analytes as necessary. Especially, addition of a metal tag has the advantage to use ICP-MS for sensitive and highly selective detection. Therefore, this method by metal tag with using LC-ICP-MS is expected as the newest ultra-trace analytical technique for proteins and metabolites.