Investigation of the HPLC-IT-TOF-MS Technique with Atmospheric Pressure Chemical Ionization for Speciation of Selenoaminoacids,Dimethyldiselenide, and Diphenyldiselenide

The simultaneous determination of selenomethionine, selenoethionine, selenocystine, dimethyldiselenide, and diphenyldiselenide was investigated for the first time by a hyphenated HPLC-IT-TOF-MS technique using atmospheric pressure chemical ionization (APCI). Alkylselenides and phenyldiselenides and also the most common selenoamino acids were successfully determined after optimization of the instrumental and procedural parameters of the above system. Non-polar columns were studied in order to obtain baseline separation and speciation in less than 10 min. Selenium speciation was achieved successfully after optimization of the instrumental and procedural parameters of the aforementioned system. The APCI interface was studied at different zone temperatures and the most characteristic ions for each analyte were defined using both positive and negative polarity. The detection limits of the six selenium species ranged between 13 and 59 µg/L and the relative standard deviation was between 4.2 and 9.3%, respectively.