DETERMINATION OF ORGANOMETALLIC SPECIES BY GAS-CHROMATOGRAPHY INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY

The development is described of a gas chromatography-inductively coupled plasma mass spectrometry (GC-ICP-MS) coupling system for the determination of organometallic species of tin, mercury and lead. The compounds are separated by GC using a 30 m long capillary column. A heated transfer line, made from quartz, directs the capillary column to just in front of the argon plasma and serves as the sample introduction system. The ionized elements are simultaneously detected on-line by ICP-MS. The real-time transient signals of the different isotopes are recorded, and an integration system allows one to calculate the retention times and to quantify the species after calibration. With the help of standard solutions the instrumental limits of detection for GC-ICP-MS of various organometallic species such as methyl, butyl or phenyl compounds of tin, mercury and lead have been calculated. The detection limit for tin is about 50 fg, for lead about 100 fg and for mercury about 120 fg. The reproducibility of different runs is better than 5%, For the application of GC-ICP-MS to environmental samples a new method using sodium tetraethylborate for direct ethylation of the ionic organotin species in wet sediments was adopted for a simultaneously multi-element in-situ ethylation of the tin, lead and mercury species.