Fully automated chromatographic purification of Sr and Ca for isotopic analysis

Abstract

We present a commercially-available, fully-automated, offline chromatography method capable of simultaneously purifying both Ca and Sr for stable and radiogenic isotope analysis. The method features effective purification and mutual separation of Ca and Sr from complex matrixes using a single, highly-reusable chromatographic column. Low carryover combined with high yield for multiple extractions indicates the column can be reused for at least 200 samples. Accurate and precise stable and radiogenic isotope data are presented for BCR-2 basalt, NIST-1400 bone ash, IAPSO seawater, and an in-house llama bone standard (CUE-0001). The Sr–Ca method was designed to accommodate a wide variety of sample types, including carbonates, bones, and teeth; silicate rocks and sediments; fresh and marine waters; and biological samples such as blood and urine. The system is highly adaptable and capable of processing up to 60 samples per run at a rate of 32 samples per day on a single chromatographic column during unattended operation.