Simultaneous determination of tetrathiomolybdates and molybdates in spiked blood plasma by differential pulse voltammetry and their speciation.
A selective, sensitive and reliable voltam- metric method for the simultaneous determination of MoS(2-)(4) and MoO(2-)(4) has been developed. The reduction of HgMoS(4) at -0.43 V and the reduction of Mo as complex of MoO(2)-oxine(2) at -0.63 V in acetate buffer at pH 4.9 are utilized for the simultaneous determination by differential pulse cathodic stripping voltametry (DPCSV). Cadmium and lead form complexes with MoS(2-)(4), but do not interfere with the determination. The limit of detection is 0.59 microg/l Mo for MoS(2-)(4) and 1.8 microg/l Mo for MoO(2-)(4). The R.S.D at a concentration level of 20 microg/l is 4.7% for MoO(2-)(4) and 3.6% for MoS(2-)(4). The method is applied to spiked blood plasma samples for the determination of free tetrathiomolybdates and molybdates. Additionally, labile tetrathiomolybdates and molybdates can be determined in spiked blood plasma after treatment of the sample with 0.15 mol/l KCN and ultrafiltration.
Giroussi
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ST
Postgraduate student, scholarship holder of Greek State Scholarship Foundation Analytical Chemistry Laboratory, Department of Chemistry, Aristotle University of Thessaloniki, GR-54006, Thessaloniki, Greece.
Voulgaropoulos
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AN
Ayiannidis
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A