Determination of lead in a chloride matrix by atomic absorption spectrometry using electrothermal vaporization and capacitively coupled plasma atomization

Abstract

A simple and rapid method using graphite furnace vaporization and plasma atomization for the determination of lead in a sodium chloride matrix was developed. Samples were injected into the furnace of a commercial graphite furnace atomic absorption/plasma emission spectrometer. A relatively low vaporization temperature of 750 °C was used to vaporize lead chloride preferentially from the bulk sodium chloride matrix. The lead chloride molecules were then atomized by a capacitively coupled plasma. The lead atomic absorption signal is, therefore, separated from the sodium chloride background absorption temporally. Detection limits (3σ) in 3% m/v sodium chloride are 4 and 40 pg of lead using peak absorbance and integrated absorbance, respectively, for a 20 µl sample. The direct determination of lead in sea-water, however, suffers from matrix effects due to magnesium sulfate. Addition of oxalic acid as a chemical modifier eliminates the magnesium sulfate interference. Detection limits (3σ) in a sea-water matrix are 28 and 2 pg of lead using peak absorbance and integrated absorbance, respectively. The precision of the method is ≤7% RSD (five replicates of 20 µl of a 25 ng ml^–1 Pb sample in either a sodium chloride or sea-water matrix).

References

1. W. Slavin and D. C. Manning, Anal. Chem., 1978, 50, 1234.
2. W. Slavin and D. C. Manning, Appl. Spectrosc., 1983, 37, 1.
3. M. P. Bertenshaw, D. Gelsthorpe and K. C. Wheatstone, Analyst, 1982, 107, 163.
4. B. V. L'vov, Spectrochim. Acta, Part B, 1978, 33, 153.
5. M. C. Halliday, C. Houghton and J. M. Ottaway, Anal. Chim. Acta, 1980, 119, 67.
6. W. Slavin, D. C. Manning and G. R. Carnrick, Anal. Chem., 1984, 56, 163.
7. D. A. Segar and J. G. Gonzalez, Anal. Chim. Acta, 1972, 58, 7.
8. D. J. Churella and T. R. Copeland, Anal. Chem., 1978, 50, 309.
9. J. A. Krasowski and T. R. Copeland, Anal. Chem., 1979, 51, 1843.
10. W. G. Brumbaugh and S. R. Koirtyohann, Anal. Chem., 1988, 60, 1051.
11. J. P. Erspamer and T. M. Niemczyk, Anal. Chem., 1982, 54, 2150.
12. B. C. Blades and D. C. Liang, Anal. Chem., 1988, 60, 27.
13. M. W. Blades and T. D. Hettipathirana, Spectrochim. Acta, Part B, 1992, 47, 493.
14. M. W. Blades and D. C. Liang, Spectrochim. Acta, Part B, 1989, 44, 1059.
15. M. W. Blades, D. C. Liang and P. R. Banks, Spectroscopy, 1992, 7, 36.
16. R. E. Sturgeon, S. N. Willie, V. T. Luong and S. S. Berman, Anal. Chem., 1990, 62, 2370.
17. M. W. Blades, D. C. Liang, D. Steel and D. L. Smith, Spectrochim. Acta, Part B, 1990, 45, 493.
18. M. W. Blades, Spectrochim. Acta, Part B, 1994, 49, 47.
19. R. E. Sturgeon, S. N. Willie, V. T. Luong and S. S. Berman, J. Anal. At. Spectrom., 1990, 5, 635.
20. M. W. Blades and T. D. Hettipathirana, J. Anal. At. Spectrom., 1992, 7, 1039.
21. M. W. Blades and T. D. Hettipathirana, J. Anal. At. Spectrom., 1993, 8, 955.
22. R. E. Sturgeon, S. N. Willie and V. T. Luong, Spectrochim. Acta, Part B, 1991, 46, 1021.
23. R. E. Sturgeon, S. N. Willie, V. T. Luong and J. G. Dunn, Appl. Spectrosc., 1991, 45, 1413.
24. Annual Book of ASTM Standards 1989, Amercian Society for Testing and Materials, Philadelphia, PA, 1989, vol. 11 02, Standard D 1141.
25. A. Varma, CRC Handbook of Furnace Atomic Absorption Spectroscopy, CRC Press, Boca Raton, FL, 1990, p. 199.
26. CRC Handbook of Chemistry and Physics, ed. Weast, R. C., Astle, M. J., and Beyer, W. H., CRC Press, Boca Raton, FL, 64th edn., 1983.
27. H. Falk, Spectrochim. Acta, Part B, 1984, 39, 387.
28. W. Slavin, D. C. Manning and S. A. Myers, Anal. Chim. Acta, 1980, 117, 267.
29. C. W. Fuller, At. Absorp. Newsl., 1977, 16, 106.
30. J. P. Erspamer and T. M. Niemczyk, Anal. Chem., 1982, 54, 538.
31. P. R. Sthapit, J. M. Ottaway, D. J. Halls and G. S. Fell, Anal. Chim. Acta, 1984, 165, 121.
32. J. D. H. Honnay, G. Honnay, E. G. Cox, O. Kennard, M. V. King, Crystal Data Determinative Tables, American Crystallographic Association, New York, 2nd edn. 1963.
33. J. Y. Cabon and A. Le Bihan, Spectrochim. Acta, Part B, 1996, 51, 1245.
34. M. Tominaga, K. Bansho and Y. Umezaki, Anal. Chim. Acta, 1985, 169, 171.
35. Lange's Handbook of Chemistry, ed. Dean, J. A., McGraw-Hill, New York, 14th edn., 1992.
36. T. Kántor, Spectrochim. Acta, Part B, 1995, 50, 1599.
37. B. Welz, Atomic Absorption Spectroscopy, VCH, Weinheim, 2nd edn., 1985, p. 53.
38. Q. Wu and G. E. Batley, Anal. Chim. Acta, 1995, 309, 95.
39. J. Pérez-Peña, C. Collado-Sánchez, M. D. Gelado-Caballero, J. A. Herrera-Melian and J. J. Hernández-Brito, Anal. Chim. Acta, 1996, 320, 19.
40. Kh. Brainina and E. Neyman, Chemical Analysis Vol. 126 Electroanalytical Stripping Methods, Wiley, New York, 1993, p. 115.