Laser ablation split stream for in situ sulfur isotope and elemental analysis

Abstract

In situ sulfur (S) isotope ratios and trace element chemistry were simultaneously determined in a wide selection of different (natural) sulfides and sulfates using femtosecond laser ablation split stream (fsLASS) inductively coupled plasma mass spectrometry (ICP-MS). The laser aerosol is split between a sequential quadrupole ICP-MS for trace element quantification and a multi-collector ICP-MS (MC-ICP-MS) for stable sulfur isotope ratio measurements. This LASS method is able to simultaneously determine S isotope ratios and element chemistry without a compromise in the measurement precision and measurement accuracy of the S isotope ratios. The quantification of major and trace elements in sulfide minerals down to the μg g⁻¹ level was achieved. LASS shows overall lower sensitivity and higher limits of detection in comparison to direct trace element determination using LA-ICP-MS only, due to the lower amounts of sample introduced into the ICP-qMS. This compromise is acceptable given the additional information gained from obtaining simultaneously both the isotopic and elemental compositions.