Determination of selenoprotein P in submicrolitre samples of human plasma using micro-affinity chromatography coupled with low flow ICP-MS

Se-containing proteins play an important role in human metabolic processes such as antioxidant action. However, speciation analysis of Se-containing proteins in biological samples is challenging because of their small amounts. In order to determine selenoprotein P (Sel-P) in human plasma, separation performance was compared between size exclusion chromatography and affinity chromatography. It was found that affinity chromatography showed better separation performance for Sel-P. Micro-affinity chromatography coupled with low flow ICP-MS was developed, which enabled separation analysis of Sel-P in sub-ml samples. Standard solution flow rate ranges for low sample consumption and total consumption nebulizers were investigated. Moreover, the stability analysis for each nebulizer with the change in composition of the mobile phase was investigated. Finally, using the developed micro-affinity chromatography coupled with the low flow ICP-MS, Sel-P and the other Se-containing proteins in sub-ml samples of human plasma were determined.