Liquid chromatographic analysis of mercury(ii) and cadmium(ii) using dimethylglyoxal bis-(4-phenyl-3-thiosemicarbazone) as derivatizing reagent

Abstract

A liquid chromatographic method based on precolumn derivatization with dimethylglyoxal bis-(4-phenyl-3-thiosemicarbazone) (DMBS) has been developed for quantitative analysis of Hg(II) and Cd(II) and separation of Hg(II), Cd(II), VO(II), and Ag(I). The complexes were separated on a 25 cm × 4.6 mm i.d., 10-μm particle, C 18 column with methanol-water-acetonitrile-1 mM tetrabutylammonium bromide (TBAB) 48:32:18:2 (v/v) as mobile phase at a flow rate of 1 mL min −1 . UV detection was at 258 nm. Linear calibration plots were obtained in the ranges 0.5-10.0 μg mL −1 for Hg(II), 0.5-12.0 μg mL −1 for Cd(II), 2-10 μg mL −1 for V, and 1.5-12.5 μg mL −1 for Ag(I), with detection limits of 50, 125, 400 and 400 pg, respectively, per 20-μL injection. Several metal ions tested did not affect the determination of mercury and cadmium. The method was used for quantitative analysis of Hg and Cd in freshwater fish, tea leaves, and tobacco. The Hg content of the samples was 0.067-0.284, 0.011-0.123, and 0.042-0.261 μg g −1 , respectively, with relative standard deviations (RSD) from 0.8 to 4.4%. The Cd content of fish, tea leaves, and tobacco was 0.0068-0.0236, 0.233-0.712, and 0.171-1.126 μg g −1 , respectively, with RSDs from 1.4 to 4.7%. Higher concentrations of Hg and Cd were observed in blood samples from smokers on dialysis than in those from healthy nonsmokers.

Using a Simple Magnetic Adsorbent for the Preconcentration and Determination of Ga(III) and In(III) by Electrothermal Atomic Absorption Spectrometry

“…Ga(III) can be determined by molecular absorption spectrometry using ligands that form compounds with high molar absorptivity [ 20 , 21 , 22 , 23 ], whose sensitivity can be improved by coupling to a liquid- [ 24 ] or solid-phase extraction procedure [ 25 ]. If the compound resulting from the interaction of Ga(III) with the ligand emits fluorescence, sensitivity is further enhanced [ 26 ].…”