Evaluation of a commercially available microconcentric nebulizer for inductively coupled plasma mass spectrometry

Abstract

The performance of a commercially available microconcentric nebulizer (MCN-100, CETAC Technologies, USA) operated at flow rates ranging from ⩽0.001 up to 0.65 ml min–1 was evaluated using a Perkin-Elmer Sciex ELAN 5000 ICP-mass spectrometer. The observations made were compared with those for the standard GemTip cross-flow nebulizer. Registration of signal behaviour plots (signal intensity as a function of the nebulizer gas flow rate) at different rf powers and at different sample uptake rates allowed firstly, a systematic optimization of the operation parameters, and secondly, a comparison of the signal 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. Also, the level and the behaviour of oxide and doubly charged ions was studied. Furthermore, the susceptibility to matrix effects was investigated using synthetic matrices of different origin (acid, organic and high salt content) and it was demonstrated that, generally, matrix effects observed with both nebulizers are comparable and the MCN-100 can be used with NaCl concentrations up to 4 g l–1 without capillary blocking. Finally, it is illustrated that the MCN-100 can be applied at sample flow rates of < 5 µl min–1, as are encountered when coupling capillary zone electrophoresis to ICP-MS for elemental speciation studies.