Optimization of dimethyltin chloride determination by hydride generation gas phase molecular absorption spectrometry using a central composite design

A factorial design is applied to the optimization of the determination of dimethyltin chloride by hydride generation gas phase molecular absorption spectrometry (HG-GPMAS). A method is described for the determination of dimethyltin chloride after conversion into gaseous dimethyltin hydride by adding a sodium tetrahydroborate (III) solution. The hydride generated is collected in a liquid nitrogen cryogenic trap. This is revolatilized, driven to the quartz flow cell and measured with gas phase molecular absorption spectrometry (GPMAS) with diode array detection. A Plackett-Burmann design is used for the study of the factors that influence the absorption signal. The optimization of these factors is performed using a central composite design. The spectra obtained over a wide range of wavelengths, 190–220 nm, allow the multivariate calibration to be studied. The parameters affecting the production and collection of the dimethyltin hydride are studied. The detection limit obtained is 3.2 ng ml−1. The precision (RSD=4.1%) is calculated from a solution containing ten times the corresponding detection limit. The recoveries (99–108%) are satisfactory. A study is made of the influence of several interferent ions (hydride generators, transition metals and anions) in the presence of dimethyltin chloride.