Ca isotopic analysis of laser-cut microsamples of (bio)apatite without chemical purification

We report methodological innovations and an initial application to retrieve Ca isotopic (δ44/40Ca) compositions of (bio)apatite at high spatial resolution. We utilize laser-microsampling via laser-cut polygons followed by extraction of μg-sized bioapatite fragments; and apply a 1010 Ω resistor for 40Ca and parafilm-dam loading to minimize in-run Ca isotope fractionation for TIMS analysis. We obtain identical internally-normalized TIMS Ca...