Determination of metal impurities in sulfamic acid by isotope dilution electrothermal vaporization inductively coupled plasma mass spectrometry

Abstract

Metal impurities present at sub-ng g^–1–ng g^–1 levels in high-purity sulfamic acid reagents were determined by isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS) with sample introduction by electrothermal vaporization (ETV). Matrix constituents causing suppression and enhancement of analyte signals were removed from the sample introduction system at the pyrolysis stage before ETV-ICP-MS measurement. As the ETV device, both tungsten and graphite furnaces were employed. In graphite furnace ETV-ICP-MS, it was necessary to use a chemical modifier in order to enhance the signal sensitivity and to obtain a linear calibration graph. In tungsten furnace ETV-ICP-MS, a linear relationship between the analyte mass and the signal was achieved without the use of a modifier but the stability of the isotope ratio measurement was slightly poorer than that in graphite furnace ETV-ICP-MS. The relative standard deviations obtained by ETV-ICP-MS using both furnaces were 6–30%. The analytical results for two types of sulfamic acid reagent obtained by tungsten furnace ETV-ICP-MS agreed with those obtained by graphite furnace ETV-ICP-MS.

References

1. A. Hioki, A. Kokubun and M. Kubota, Analyst, 1994, 119, 1879.
2. A. L. Gray and A. R. Date, Analyst, 1983, 108, 1033.
3. N. Shibata, N. Fudagawa and M. Kubota, Anal. Chim. Acta, 1992, 265, 93.
4. C. J. Park and G. E. M. Hall, Curr. Res. Geol. Survey Can., 1986, 861B, 767.
5. D. C. Gregoire, Anal. Chem., 1990, 62, 141.
6. R. D. Ediger and S. A. Beres, Spectrochim. Acta, Part B, 1992, 47, 907.
7. C. J. Park and G. E. M. Hall, J. Anal. At. Spectrom., 1987, 2, 473.
8. M. Komoda, K. Chiba and H. Uchida, Anal. Sci., 1996, 12, 21.
9. D. C. Gregoire and H. Naka, J. Anal. At. Spectrom., 1995, 10, 823.
10. R. J. Bowins and R. H. McNutt, J. Anal. At. Spectrom., 1994, 9, 1233.
11. C. Chang and S. Jiang, J. Anal. At. Spectrom., 1997, 12, 75.
12. C. J. Park, J. C. van Loon, P. Arrowsmith and J. B. French, Can. J. Spectrosc., 1987, 32, 29.
13. C. J. Park, J. C. van Loon, P. Arrowsmith and J. B. French, Anal. Chem., 1987, 59, 2191.
14. N. Shibata, N. Fudagawa and M. Kubota, Anal. Chem., 1991, 63, 636.
15. D. M. Goltz, D. C. Gregoire and C. L. Chakrabarti, Can. J. Appl. Spectrosc., 1996, 41, 70.
16. M. Suzuki, K. Ohta and T. Yamakita, Anal. Chem., 1981, 53, 9.
17. K. G. Heumann, in Inorganic Mass Spectrometry, ed. Adams, F., Gijbels, R., and van Grieken, R., Wiley, New York, 1988, ch. 7, pp. 308–311.
18. P. de Bievre, M. Gallet, N. E. Holden and I. L. Barnes, J. Phys. Chem. Ref. Data, 1984, 13, 809.
19. D. C. Gregoire and H. Naka, J. Anal. At. Spectrom., 1995, 10, 823.
20. D. L. Tsalev, V. I. Slaveykova and P. B. Mandjukov, Spectrochim. Acta Rev., 1990, 13, 225.
21. K. Ouishi, K. Yasuda, Y. Morishige and K. Hirokawa, Fresenius' J. Anal. Chem., 1994, 348, 195.
22. W. C. Campbell and J. M. Ottaway, Talanta, 1974, 21, 837.
23. D. C. Gregoire, S. Al-Maawali and C. L. Chakrabarti, Spectrochim. Acta, Part B, 1992, 47, 1123.
24. T. Kantor, Spectrochim. Acta, Part B, 1988, 43, 1299.
25. R. Thukahara and M. Kubota, Spectrochim. Acta, Part B, 1990, 45, 779.
26. E. S. Beary, J. D. Fassett, K. R. Eberhaedt and R. L. Watter, The Second Draft on the Isotope Dilution ICP-MS Protocol for the Determination of Lead in Water, National Institute of Standards and Technology, Gaithersburg, MD, 1996.