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International audience; The demand for large and reliable datasets on isotopic composition has increased ingeochemistry and environmental sciences over recent years. We present an automated ionchromatographic separation method using a robotic pipetting arm, termed “ChemCobOne”, toreduce the time of sample separation. Its performance was tested for lithium isotope separationin geological reference materials using a single-step separation with HCl (0.2 mol l-1) and a 2-mlresin volume. This refined lithium purification method does not forfeit precision, accuracy orpurity compared with manual sample processing. In addition, a 7Li value for NASS-6 of 30.99 ±0.50‰ (2s) (95%CI = 0.14‰, n = 44) was determined and the first 7Li values for the granite rock

Rationale During transient signal acquisition by Multi-Collection Inductively Coupled Plasma Mass Spectrometry (MC-ICPMS), an isotope ratio increase or decrease (isotopic drift hereafter) is often observed which is related to the different time responses of the amplifiers involved in multi-collection. This isotopic drift affects the quality of the isotopic data and, in a recent study, a method of internal amplifier signal synchronization for isotope drift correction was proposed. In this work the determination of the amplifier time constants was investigated in order to validate the method of internal amplifier signal synchronization for isotope ratio drift correction. Methods Two different MC-ICPMS instruments, the Neptune and the Neptune Plus, were used, and both the lead transient signals and the signal decay curves of the amplifiers were investigated. Results Our results show that the first part of the amplifier signal decay curve is characterized by a pure exponential decay. This part of the signal decay was used for the effective calculation of the amplifier first-order time constants. The small differences between these time constants were compared with time lag values obtained from the method of isotope signal synchronization and were found to be in good agreement. Conclusions This work proposes a way of determining amplifier first-order time constants. We show that isotopic drift is directly related to the amplifier first-order time constants and the method of internal amplifier signal synchronization for isotope ratio drift correction is validated. Copyright © 2015 John Wiley & Sons, Ltd.