Anal. Chem. 2008, 80, 344
Correction Measurement of Femtogram Quantities of Protactinium in Silicate Rock Samples by Multicollector Inductively Coupled Plasma Mass Spectrometry Marcel Regelous,* Simon Turner, Tim Elliott, Kia Rostami, and Chris Hawkesworth (Anal. Chem. 2004, 76, 3584-3589).
We have recently become aware of an error in the spreadsheet used to calculate the 231Pa concentrations and (231Pa/235U) activity ratios of the rock samples listed in Table 4 of the above paper. The correct 231Pa concentrations and (231Pa/235U) ratios are given in Table 1. The corrected 231Pa concentrations of the samples are 1.7% lower, and the (231Pa/235U) activity ratios are 2.0% higher than those listed in Table 4 of the original publication. These corrections do not change significantly the conclusions in the original paper1 except that the accuracy of our (231Pa/235U) data, based on measurements of rock samples that are presumed to be in secular equilibrium, is probably closer to 2%. The Pa concentrations and (231Pa/235U) ratios reported in a later publication from this laboratory2 are correct. Table 1. Corrected 231Pa Concentrations and (231Pa/ 235U) Ratios of Silicate Rock Samples Analyzed by Regelous et al.1 (fg/g)
U (ppm)
(231Pa/235U)
(234U/238U)
500.4 ( 6.1 496.2 ( 3.5 128.9 ( 1.6 3400.2 ( 29 3454.0 ( 23 3527.9 ( 25 292.4 ( 2.1 292.9 ( 1.8
0.679 0.679 0.472 10.365 10.508 10.549 0.8778
2.266 2.247 0.840 1.008 1.011 1.028 1.024
nda nd 1.009 nd nd 1.010 1.000
231Pa
RW35 RW35r FON39 LV18a LV18b LV18(2) LP96-36 LP96-36 a
nd, not determined.
ACKNOWLEDGMENT We thank Julie Prytulak for pointing out to us the above error, and for many helpful discussions. AC702316R 10.1021/ac702316r Published on Web 12/06/2007
* To whom correspondence should be addressed. E-mail: m.regelous@ gl.rhul.ac.uk. (1) Regelous, M.; Turner, S. P.; Elliott, T. R.; Rostami, K.; Hawkesworth, C. J. Anal. Chem. 2004, 76, 3584-3589. (2) Turner, S.; Regelous, M.; Hawkesworth, C. J.; Rostami, K. Geochim. Cosmochim. Acta 2006, 70, 480-503.
344 Analytical Chemistry, Vol. 80, No. 1, January 1, 2008
10.1021/ac702316r CCC: $40.75
© 2008 American Chemical Society Published on Web 12/06/2007
