IsoSpike: Improved Double‐Spike Inversion Software

The double‐spike approach for correction of instrumental mass bias in mass spectrometry data is well established. However, there is very little consistency within the scientific community in terms of double‐spike data reduction. Double‐spike solutions require computer calculation, using either geometric or algebraic approaches, and are often performed using spreadsheet calculations that vary from group to group and between isotope systems. Here, we present IsoSpike , a generalised computer procedure for the processing of double‐spike mass spectrometry data, built as an add‐on for the Iolite data‐reduction package ( www.iolite.org.au ). Use of this software permits visualisation of mass spectrometry data in a time window, and rigorous treatment and screening of data. Additionally, IsoSpike uses an integration‐by‐integration approach where the double‐spike calculations are performed on every integration within an analysis, providing straightforward quantification of uncertainties on double‐spike‐corrected isotope ratios. The advantages of this approach over traditional methods are discussed here. Platinum stable isotope data are presented as an example data set, although the procedure is applicable to any double‐spike system. IsoSpike is freely available from www.isospike.org .