Direct high-precision measurements of the Sr-87/Sr-86 isotope ratio in natural water, carbonates and related materials by multiple collector inductively coupled plasma mass spectrometry (MC-ICP-MS)

The present work presents a precise and accurate method for the determinati on of strontium isotope ratios (Sr-87/Sr-86) by multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS). Mass discrimination and instr ument drift are corrected by the use of the natural constant Sr-86/Sr-88 ra tio as an internal standard. The internal standard also corrects for matrix effects, allowing the direct analysis of natural water, carbonates and rel ated materials without chemical separation. The precision (2 sigma) of the Sr-87/Sr-86 ratio is 0.002% (20 ppm), even in samples with total dissolved solid (TDS) levels of up to 500 mg L-1.