Precise Measurement of Isotope Ratios with A Double Focusing Magnetic Sector ICP Mass Spectrometer
The potential of a commercially available double focusing magnetic sector inductively coupled plasma mass spectrometer (ICP-MS) ('Element', Finnigan MAT, Germany) for precise isotope ratio measurement at the low resolution setting (R = 300) was evaluated. Optimization of scanning conditions permitted a relative standard deviation for a set of 10 consecutive 2 min measurements of about 0.1% relative standard deviation (RSD) (for (206) Pb(+)/(207)Pb(+)) at signal intensities of about 200000 (cps) (peak height). This compares favourably with the best values ever reported for quadrupole ICP-MS and barely exceeds the theoretical value (counting statistics). Increasing the signal intensity to values 500 000 counts per second (peak height) resulted in a further reduction of the RSDs obtained (for both (25) Mg(+)/(26)Mg(+) and (206) Pb(+)/(207) Pb(+) to values of typically 0.04%. These figures are remarkably better than those reported for commercially available quadrupole ICP-MS systems. This improvement significantly reduces the difference between isotope ratio precision of ICP-MS on one hand and those of thermal ionization mass spectrometry and plasma source multiple collector mass spectrometry on the other.
Bibliographic Reference: Article: Analytical Chemistry, American Chemical Society
Record Number: 199610243 / Last updated on: 1996-03-18
Original language: en
Available languages: en