EVALUATION OF A COMMERCIALLY AVAILABLE MICROCONCENTRIC NEBULIZER FOR INDUCTIVELY-COUPLED PLASMA-MASS SPECTROMETRY

The performance of a commercially available microconcentric nebulizer (MCN-100, CETAC Technologies, USA) operated at flow rates ranging from less than or equal to 0.001 up to 0.65 ml min(-1) was evaluated using a Perkin-Elmer Sciex ELAN 5000 ICP-mass spectrometer, The observation s made were compared with those for the standard GemTip cross-bow nebu lizer, Registration of signal behaviour plots (signal intensity as a f unction of the nebulizer gas bow rate) at different rf powers and at d ifferent sample uptake rates allowed firstly, a systematic optimizatio n of the operation parameters, and secondly, a comparison of the signa l behaviour observed when using both types of nebulizer, The stability of the MCN-100 was evaluated at different sample uptake rates and the occurrence of memory effects was checked for a number of elements, Al so, the level and the behaviour of oxide and doubly charged ions was s tudied, Furthermore, the susceptibility to matrix effects was investig ated using synthetic matrices of different origin (acid, organic and h igh salt content) and it was demonstrated that, generally, matrix effe cts observed with both nebulizers are comparable and the MCN-100 can b e used with NaCl concentrations up to 4 g l(-1) without capillary bloc king, Finally, it is illustrated that the MCN-100 can be applied at sa mple flow rates of <5 mu l min(-1), as are encountered when coupling c apillary zone electrophoresis to ICP-MS for elemental speciation studi es.