The Prestudy for Studying Inorganic Nutrient Metabolism in Humans : the Aplication of ICP-MS for Determination of Stable Isotope Ratio of Fe and Zn

A method is described for the determination of isotope ratio of Fe and Zn by means of inductively coupled plasma-mass spectrometry (ICP-MS). The mass spectrometer was operated in low resolution mode to provide maximal sensitivity. Typical conditions for operations were: plasma power 0.85 k W, reflected power < 5 W, coolant argon-flow rate 12 L/min, auxiliary flow rate 0.8 L/min, nebuliser flow rate 0.5 L/min, dwell time 60 msec, measuring time 5 sec, 3 repeats per integration. The repeatability and accuracy of the method was evaluated by analyzing standard stable isotop of Fe and Zn produced by ORINI (Oak Ridge National Laboratory), USA. The relative standard deviation (RSD) for all of the isotopic ratio was < 2%. The results of the stable isotop ratio 56Fe/54Fe, 57Fe/54Fe, 58Fe/54Fe, dan 64Zn/67Zn, 66Zn/67Zn, 68Zn/67Zn, 70Zn/67Zn measured by ICP-MS showed a good level of agreement with TIMS (thermal ionization mass spectrometry). This method was prepared for studying the absorption and/or metabolism of inorganic nutrients in humans. (author)