SULFUR ISOTOPE RATIO (S-34 S-32) MEASUREMENTS IN PLANT-MATERIAL BY INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY/

The S-34:S-32 isotope ratio in plant material mas determined using mea surements 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 ma ss 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 me asurements for a sulfur solution containing 17 mg l(-1) was characteri zed by an RSD of <1%, Results for plant material enriched in YS mere i n agreement with those obtained by magnetic deflection mass spectromet ry using electron ionization at the 95% confidence level. A sample thr oughput of 45 h(-1) was achieved.