Four As compounds were successfully separated and detected by single-column ion chromatography with inductively coupled plasma (ICP) mass spectrometric detection. The mass spectral interferent ArCl+ was reduced by chromatographically resolving chloride from the negatively charged arsenic species. Determination of four As species was investigated in urine, club soda and wine. Detection limits of 0.16 ng of As(III), 0.26 ng of As(v), 0.073 ng of dimethylarsinic acid (DMA) and 0.18 ng of methylarsonic acid (MMA) in wine were obtained. Sensitivity was further improved by using an He-Ar mixed gas ICP as the ionization source. However, the intensity of the ArCl+ interference was also increased using this plasma. Detection limits of 0.063 ng of As(III), 0.037 ng of As(v), 0.032 ng of DMA and 0.080 ng of MMA in club soda were achieved using the He-Ar plasma source. Similar limits of detection were found in urine and wine.

An He -Ar mixed gas inductively coupled plasma (ICP) was investigated for use as an ion source for plasma mass spectrometry (MS). The addition of He to Ar produces a plasma capable of ionising high ionisation potential elements more efficiently than the pure Ar plasma. The best signal to noise ratios for metallic elements were obtained with a 20% He plasma, and for halides with a 30% He plasma. The He -Ar mixed gas plasma shows an improvement of one order of magnitude in the detection limits of several metallic elements studied and an improvement of two orders of magnitude for non-metals in comparison with Ar ICP-MS. Figures of merit, including detection limits, linear dynamic ranges, metal oxide ratios and doubly to singly charged ion ratios, are reported and compared with those for Ar ICP-MS.

Ion chromatography has been combined with inductively coupled plasma mass spectrometry for the speciation of arsenic compounds commonly found in urine. Ion chromatography was used to eliminate or reduce the mass spectral interference formed from chloride, namely argon chloride, by resolving chloride chromatographically from the arsenic compounds. A 20-fold dilution of the urine samples was necessary in order t o avoid column overloading from chloride and subsequent argon chloride interference. Detection limits in urine of 3.4 p.p.b. As"', 4.2 p.p.b. As" and 7 p.p.b. dimethylarsinic acid were obtained. Three commercially available freeze-dried urine standards were analysed using the standard additions method. Good agreement was obtained for total arsenic content, which was calculated from the sum of the species with accepted arsenic concentration. The relative standard deviation of peak height for each of the species was approximately 5% in urine.

Supercritical fluid chromatography coupled with inductively coupled plasma mass spectrometry shows high potential for the determination at ultratrace levels of organometallic compounds of environmental interest. In this study the determination of organotin compounds at ultratrace levels is demonstrated. In this work a supercritical fluid chromatography/inductively coupled plasma mass spectrometry (SFC/ICPMS) interface was developed. Separation of tetraalkyltin compounds shows detection levels in the subpicogram range (0.034 pg for tetrabutyltin; 0.047 pg for tetraphenyltin). The linear ranges are over 3 orders magnitude (1-1000 pg). The reproducibility of sample injections are better than 5% RSD.

A single microwave digestion procedure was developed for use with a variety of seafood products. Inductively coupled plasma atomic emission and mass spectrometry were used to determine the levels of As, Cd and Pb in samples of tuna, salmon, shrimp, walleye, clams, oysters and lobster. The precision for ten replicate analyses of clams was 2.1% for As at the 10.0 pg g-1 level, 5.6% for Pb at the 0.067 pg g-1 level and 2.5% for Cd at the 0.079 pg g-1 level. Acceptable spike recoveries in each of the sample types were achieved using both detection methods. Results for two standard reference materials were in good agreement with certified values