ICP-TOFMS can be used to analyze e.g. the composition of individual particles and cells and offers the unique possibility of analyzing several elements quasi simultaneously. The major challenge is to cover the widest possible dynamic signal range so that major and trace elements can always be measured and quantified. Detection plays an important role. Detectors for ICP-MS devices cover up to 10 orders of magnitude of signal range (various manufacturer’s communication). However, these working ranges are considered per second, i.e. 1 - 1e10 cps, and require a split between 'ion counter' and 'analogue’ mode. For the measurement of signals from single particle events or in kHz laser ablation mapping, however, this working range is reduced to about 1-1000 counted ions per event. This is not only the case for TOFMS but for all ICP-MS since the signal duration is one millisecond or less and automatic switching between detection modes during the signal rise time is not possible.

For sp-ICP-MS and fast LA mapping, it is of the highest priority that the three orders of magnitude of detector working range are optimally utilized, i.e. that both main and trace elements can be well detected. A general attenuation of the ion beam to address detector saturation by the main elements should be avoided, as the signals of the trace elements would fall below detectability. Blanking of the main elements is also not expedient, as the multi-element information is lost, and any quantification becomes impossible. The combination of notch filter attenuation with the linear response of a MCP detector offers the unique feature of simultaneous quantitative analysis of elements in individual particles and with more than three orders of magnitude difference in analyte mass.

We show how notch filter technology can be used to specifically reduce the signal intensity of major elements while preserving the sensitivity for trace elements to simultaneously analyze major and trace elements in particles with analyte mass differences exceeding three orders of magnitude.