Improving Precision and Signal/Noise Ratios for MC-ICP-MS

High precision measurements of isotope ratios are improved by continuous innovations in multi-collector isotope ratio mass spectrometers. Recently, the Thermo Scientific TRITON Plus TIMS and NEPTUNE Plus MC-ICP-MS benefitted from the implementation of Faraday cup current amplifiers with 1013 ohm feedback resistors. This significantly improves the signal/noise ratio of ion beam measurements and the reproducibility of isotope ratios derived from low ion beam intensities (fA range). On the NEPTUNE Plus, these innovations follow the development of the Jet Interface option, itself enabling significant increases in ion beam intensities for both solution and laser ablation measurements. This paper presents data for uranium isotope ratios obtained with a NEPTUNE Plus equipped with both 1011 and 1013 ohm Faraday cup current amplifiers. The data presented here illustrate the benefits of such technology developments, which will have applications in the geosciences, environmental, nuclear and biomedical fields.