DETERMINATION AND SPECIATION OF ORGANOTIN COMPOUNDS BY GAS-CHROMATOGRAPHY MICROWAVE-INDUCED PLASMA-ATOMIC EMISSION-SPECTROMETRY

An optimized analytical method for the determination of organotin comp ounds in environmental samples is described. After derivatization the resulting compounds were measured with a hyphenated technique, gas chr omatography coupled with element-selective detection by helium atmosph eric pressure microwave induced plasma atomic emission spectrometry (G C-MIP-AES). The sensitivity of the most intensive emission lines in th e range of 180-350 nm was investigated. The best results were obtained by using the 326.23 nm line. The influence of the reagent gases (H-2, O-2) on the signal intensity was determined. After the optimization of the source conditions a calibration was realized on the base of a mul ticomponent standard solution, prepared by pentylation of organotin sa lts. A detection limit of 0.8 pg Sn could be achieved. Measurements of the sensitivity on mixtures of organotin compounds with different alk ylation showed a dependence of the grade of pentylation. This could be caused by plasma effects (formation of CO and OH molecular bands). Th e proposed method was applied to the analysis of organotin compounds i n a sediment of the Elbe river. Furthermore, a new arrangement of GC-M TP-AES was studied. It consists of a gas chromatograph, directly coupl ed to a newly designed MIP (without interface) and a quartz fibre opti cs to transmit the emitted light to the spectrometer. Parameters, such as gas flow, power of the microwave generator, distance of the capill ary column to the plasma, were optimized.