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A graphite cup inserted into a graphite tube was investigated for the direct analysis of solid samples using graphite furnace AAS. Arsenic, cadmium, chromium, copper, lead and manganese were determined in reference materials, Atomisation from the cup delays sample volatilisation until the tube has stabilised in temperature so that the same effect is obtained as with a L'vov platform. Background attenuation and non-spectral interferences are substantially reduced under these near-thermal equilibrium conditions, so that all determinations can be carried out against acid reference solutions. The reproducibility of the results is typically around 10%. The values obtained are not always within the recommended or certified range; the accuracy is more than acceptable, however, for a semi-quantitative determination or for screening purposes.

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The use of microsampling flow injection inductively coupled plasma mass spectrometry for the multi-elemental analysis of samples containing large amounts of total dissolved solids is described. The flow injection parameters such as sample delivery rate and sample loop volume were optimized with respect to signal peak height and stability. Short-(5 min) and long-(>2 h) term precision of the technique were investigated and detection limits in a 3% m/v NaCl matrix were determined. The detection limits for flow injection were 2-5 times better than those for continuous flow sample aspiration of the same matrix. Standard reference rock material AGV-1 from the United States Geological Survey was analysed after lithium tetraborate fusion (>I .2% m/v salt) to demonstrate the accuracy of the proposed method. Recovery experiments were carried out using spiked (10 ,ug I-') 1 and 3% m/v NaCl solutions and were found to be acceptable for such matrices ranging from 83 to 1 19%.

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