Simultaneous or scanning data acquisition? A theoretical comparison relevant to inductively coupled plasma sector-field mass spectrometers.

The benefits of simultaneous multichannel detection over single-channel scanning detection are well established in analytical chemistry. Multichannel detection increases duty cycle, which leads to enhanced sensitivity, detection limits, and reduced analysis time. Also, multichannel detection used with either isotope-ratio or internal-standard techniques provides a mechanism to reduce the effect of multiplicative or flicker noise prevalent in plasma sources. An additional benefit of simultaneous detection is superior analysis of short-lived transient signals. Presented here is a theoretical comparison between simultaneous/continuous multichannel acquisition and single-channel scanning acquisition. To conduct this comparison, reported sensitivity, single-channel precision, and background values for commercial inductively coupled plasma sector-field mass spectrometers (ICP-SFMS) are used to generate theoretical figures of merit for both acquisition methods. Among the figures of merit that will be considered are detection limits, precision, and analysis time, particularly for multi-element or multi-isotope analysis.