Separation of organoselenium compounds and their electrochemical detection

Abstract

A simplified procedure based on ion-exchange separation of selenourea (Se-U) and selenocystamine (Se-CM), which have very close half-wave potential when they are simultaneously analyzed by voltammetric techniques, has been developed and optimized. Thus, selenocystamine remains in the cation exchanger Purolite C 100 H, whereas selenourea is found in the effluent and is determined by square wave cathodic stripping voltammetry using Na(2)CO(3 )as electrolyte. Selenocystamine is then eluted from the cation exchanger using 4 M HCl and analyzed by square wave cathodic stripping voltammetry in the HCl solution. For each voltammetric determination the corresponding parameters were investigated and optimized; the obtained detection limits were 0.3 ng Se mL(-1) for Se-CM and 2 ng Se mL(-1) for Se-U. A flow sheet for the separation of inorganic (Se(IV) and Se(VI)) and organoselenium compounds (Se-U, Se-CM, (CH(3))(2)Se(2), and (CH(3))(2)Se) developed for their electrochemical detection is presented and it was successfully applied to a certified reference material, an environmental soil sample, and a urine sample.

Electroanalytical Techniques for the Detection of Selenium as a Biologically and Environmentally Significant Analyte—A Short Review

“…(CH 3 ) 2 Se 2 in the organic phase as well as Se(IV) in the aqueous phase were determined directly and Se(VI) and (CH 3 ) 2 Se were determined indirectly after suitable leaching. Methylated forms of selenium (Me 2 Se, Me 2 Se 2 ) are formed by microorganisms in an aqueous medium [19].…”

Chemometric Analysis of Voltammetric Data on Metal Ion Binding by Selenocystine

“…10 CSV at HMDE has also been used for speciation analysis of Se. 11,12 Simultaneous determination of Se 4+ and SeCyst in the aqueous phase and Me 2 Se 2 in the organic phase after selective extraction using CH 2 Cl 2 was successful.…”

“…The results revealed the formation of a surface film of mercuro-selenocystinate, which is energetically and kinetically more favorable than the corresponding mercuro-cystinate, prior to the reduction of the amino acids . CSV at HMDE has also been used for speciation analysis of Se. , Simultaneous determination of Se 4+ and SeCyst in the aqueous phase and Me 2 Se 2 in the organic phase after selective extraction using CH 2 Cl 2 was successful.…”

Προσδιορισμός Των Στοιχείων Της Ομάδας Της Πλατίνας Σε Σωματίδια Από Τις Εκπομπές Των Καταλυτών Βενζινοκίνητων Σχημάτων Και Αξιολόγηση Της Κατάστασης Του Καταλύτη

“…The investigation of the influence of the eluent thiourea on the voltammetric detection of Pt(IV), Pd(IV) and Rh (III) was found and the obtained voltammograms were analogous to those obtained in pure electrolyte (0.1 M HCl), as reported elsewhere. [31]. In Table 2, the half wave potentials of Pt and Pd, the sensitivities, expressed by the slope of the calibration curve and the detection limits of Pt and Pd, in the eluent of Lewatit MonoPlus TP-214 ion-exchanger (5% thiourea in 0.1 M HCl), are presented.…”