Trace Analysis and Speciation for Methylated Organotins by HPLC-Hydride Generation-Direct Current Plasma Emission Spectroscopy (HPLC-HY-DCP)

Abstract

Total tin determinations can be accomplished at trace levels (10–25 ppb) by a continuous on-line hydride generation (HY), followed by direct current plasma (DCP) emission spectroscopy (HY-DCP). This approach is applicable for organotin compounds such as mono-, di-, and trimethyltin chloride, as well as stannous and stannic cations. HY-DCP methods of total tin analysis have been applied to a number of spiked and actual samples. Detection limits, calibration plots, sensitivities, and related analytical parameters have been evaluated. Organotin analysis and speciation can be accomplished by the interfacing of this HY-DCP step with high-performance liquid chromatography (HPLC), with the use of a polymeric PRP-1 type column with an acidic, ionic mobile phase, usually containing a suitable ion-pairing reagent. The overall speciation approach, HPLC-HY-DCP, has been evaluated with regard to separation conditions; detection limits; sensitivities; calibration plots; and applications to spiked water, clam juice, seawater, and tuna fish samples. The results suggest the suitability and reliability of this HPLC-HY-DCP approach for individual tin species. Other metal species capable of forming a hydride derivative on-line, in a continuous fashion, may also be suitable for speciation by HPLC-HY-DCP.