Sulfur isotope ratio (34S:32S) measurements in plant material by inductively coupled plasma mass spectrometry

The S-34:S-32 isotope ratio in plant material mas determined using measurements at m/z 48 and 50, corresponding to the (SO+)-S-32-O-16 and (SO+)-S-34-O-16 species, respectively, by inductively coupled plasma mass spectrometry (ICP-MS), The sulfur species in aqueous solutions and plant digests were separated and pre-concentrated in an anion-exchange resin (AGI-X8) column inserted in a flow system. The isotope ratio measurements for a sulfur solution containing 17 mg l(-1) was characterized by an RSD of <1%, Results for plant material enriched in YS mere in agreement with those obtained by magnetic deflection mass spectrometry using electron ionization at the 95% confidence level. A sample throughput of 45 h(-1) was achieved.