Flow Injection Microwave-assisted Dissolution of Silicate Rocks for Magnesium Determination by Flame Atomic Absorption Spectrometry

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Marcelo Dominguez De Almeida, Kátia Christina Leandro, Christian Vidal Da Costa, Ricardo Erthal Santelli and Miguel De La Guardia


Abstract

A flow injection system based on on-line microwave-assisted digestion was tested as a tool to perform silicate rock dissolution in acid medium (HF+HNO3). A 50 mg portion of the powdered rocks was dispersed with the acid mixture and stirred for a few minutes. Using a 3.8 ml min–1 flow rate, the sample slurry was digested inside a microwave oven for 10 s. A 20 µl volume of the digested sample slurry was introduced into an aqueous carrier stream and mixed with a reagent stream containing boric acid before introduction into the AAS system. Chemical variables were studied and the best conditions were obtained with 4 m HF+1 m HNO3. Magnesium was selected as a test element. The developed procedure enables about ten samples to be analysed per hour (including sample preparation) and affords a linear dynamic range from 0.5 to 4 µg ml–1 Mg, an RSD of 0.82% (n=5) and a detection limit of 60 ng ml–1. Reference rock samples were analysed and the results obtained agreed with the certified values.


References

  1. Z. Sulcek and P. Povondra, Methods of Decomposition in Inorganic Analysis, CRC Press, Boca Raton, FL, 1989 Search PubMed.
  2. H. M. Kingston and L. B. Jassie, Introduction to Microwave Sample Preparation, ACS Professional Reference Book, American Chemical Society, Washington, DC, 1988 Search PubMed.
  3. A. Morales-Rubio, A. Salvador and M. de la Guardia, Fresenius' J. Anal. Chem., 1992, 342, 452 CrossRef CAS.
  4. M. Burguera, J. L. Burguera and O. M. Alarcón, Anal. Chim. Acta, 1988, 214, 421 CrossRef CAS.
  5. F. Lizondo, M. T. Vidal and M. de la Guardia, Analusis, 1991, 19, 136 CAS.
  6. I. Kojima, A. Kato and C. Iida, Anal. Chim. Acta, 1992, 264, 101 CrossRef CAS.
  7. J. E. Tahán, J. M. Sanchez, M. C. Rodrigues, H. S. Cubillán, V. A. Granadillo and R. A. Romero, Ciencia, 1995, 3, 139 Search PubMed.
  8. F. Smith and B. Cousins, Anal. Chim. Acta, 1985, 177, 243 CrossRef CAS.
  9. P. Wowinski and V. Hodge, At. Spectrosc., 1994, 15, 109.
  10. M. M. Totland, I. Jarvis and K. E. Jarvis, Chem. Geol., 1995, 124, 21 CrossRef CAS.
  11. R. T. Watkins, M. K. Ridley, M. A. B. Pougnet and J. P. Willis, Chem. Geol., 1995, 121, 273 CrossRef CAS.
  12. M. Feinberg, C. Suard and Ireland-Ripert, J., Chem. Int. Lab. Syst., 1994, 22, 37 Search PubMed.
  13. J. Liu, R. E. Sturgeon and S. N. Willie, Analyst, 1995, 120, 1905 RSC.
  14. V. Karanassios, F. H. Li, B. Liu and E. D. Salin, J. Anal. At. Spectrom., 1991, 6, 457 RSC.
  15. T. J. Gluodenis and J. F. Tyson, J. Anal. At. Spectrom., 1993, 8, 697 RSC.
  16. M. Burguera, J. L. Burguera and O. M. Alarcón, Anal. Chim. Acta, 1986, 179, 351 CrossRef CAS.
  17. V. Carbonell, A. Morales-Rubio, A. Salvador, M. de la Guardia, J. L. Burguera and M. Burguera, J. Anal. At. Spectrom., 1992, 7, 1085 RSC.
  18. S. J. Haswell and D. Barclay, Analyst, 1992, 117, 117 RSC.
  19. B. Welz, D. L. Tsalev and M. Sperling, Anal. Chim. Acta, 1992, 261, 91 CrossRef CAS.
  20. M. de la Guardia, V. Carbonell, A. Morales-Rubio and A. Salvador, Talanta, 1993, 40, 1609 CrossRef CAS.
  21. J. L. Burguera, M. Burguera and M. R. Brunetto, At. Spectrosc., 1993, 14, 90 CAS.
  22. C. Cabrera, Y. Madrid and C. Camara, J. Anal. At. Spectrom., 1994, 9, 1423 RSC.
  23. J. L. Burguera, M. Burguera, P. Carrero, C. Rivas, M. Gallignani and M. R. Brunetto, Anal. Chim. Acta, 1995, 308, 349 CrossRef CAS.
  24. R. E. Sturgeon, S. N. Willie, B. A. Methven and J. W. H. Lam, J. Anal. At. Spectrom., 1995, 10, 981 RSC.
  25. C. P. Hanina and S. A. McIntosh, At. Spectrosc., 1995, 16, 106.
  26. P. Torres, E. Ballesteros and M. D. Luque de Castro, Anal. Chim. Acta, 1995, 308, 371 CrossRef CAS.
  27. Ph. Quevauviller, J. L. Imbert and M. Ollé, Mikrochim. Acta, 1993, 112, 147 CAS.
  28. CRC Handbook of Chemistry and Physics, ed. Weast, R. C., CRC Press, Boca Raton, FL, 60th edn., p. B121, 1979 Search PubMed.
  29. K. Govindaraju, Geostand. Newsl., 1989, Special Issue, 11 Search PubMed.
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