Abstract: | The determination of iron isotope ratios in blood, without prior sample preparation, using inductively coupled plasma mass spectrometry (ICP-MS) with sample introduction by electrothermal vaporisation (ETV) is described. Following oral administration of 5 mg of enriched 54FeSO4 and intravenous administration of 200 micrograms of 57FeSO4 to non-pregnant women, the 54Fe: 56Fe and 57Fe: 56Fe isotope ratios in serum were measured reliably within 20 min per sample in quintuplicate. Changes in the fractional absorption of iron during human pregnancy could therefore be assessed. |