Evaluation of the multi-element capabilities of electrothermal vaporization quadrupole-based ICP mass spectrometry

Electrothermal vaporization (ETV) ICP mass spectrometry is a method that co mbines the ability or the graphite furnace to handle complex samples with t he detection power of ICP-MS. It is somewhat Surprising. however, that most works reporting on the application of this method have only described the "simultaneous" (from the same tube firing) determination of 1-3 elements. D ifferent authors have attributed this fact to the limited capability of the quadrupole filter (the most commonly used mass spectrometer ill ICP-MS ins trumentation) to deal with the transient signals that electrothermal vapori zation produces. Nevertheless, recent works suggest that the real multi-ele ment capabilities of ETV quadrupole-based ICP-MS might have been largely un derestimated. A systematic study of the number of mass-to-charge ratios tha t call be "simultaneously" monitored in ETV quadrupole-based ICP-MS without degrading the precision, the sensitivity and the limits of detection has b een carried out. Three elements with different furnace behaviours (Cd, Co a nd Ti) were chosen for the study. The effect of the dwell time and the way of processing the analytical data were also evaluated. The results indicate that, when using ETV-ICP-MS with it quadrupole-based instrument, no detrim ental effects on the precision, detection limits and sensitivity occur its long its it critical value of three or four points to define the signal pro file is achieved. This requirement corresponds to the possibility of monito ring more than 20 elements for a standard peak width of 1.5-2 s. Several op tions for further improvements are also discussed, including the possibilit y of separating (with respect to time) the vaporization of elements with di fferent furnace behaviours.