Validation of Determination and Speciation Analysis of Selenium in Urine by HPLC and Inductively-Coupled Plasma Mass Spectrometry

Abstract

The first part of this study describes determination of total Se in urine by inductively-coupled plasma mass spectrometry (ICP-MS). Determination of the most abundant Se isotope, ⁸⁰Se, by ICP-MS is complicated by interference of ⁴⁰Ar₂. This was suppressed using a dynamic reaction cell with methane. The limit of Se detection was determined and the linearity of the obtained dependence was verified by the Mandel test. The accuracy was verified by analysis of urine with a standard Se solution. In the other part, a method for separation of selenite, selenate, selenocystine, selenomethionine and selenourea in urine was elaborated using HPLC and ICP-MS. Separation of selenate, selenomethionine, selenourea was good, but the retention times of selenite and selenocystine were very close. The optimized separation parameters were used for urine analysis in septic patients and healthy volunteer control, the food of both groups being supplemented with Se. The Se concentration in the former group was very low.