Electrothermal atomic absorption spectrometry with ballast in a rapidly heated graphite furnace: determination of lead and cadmium in seawater

The processes of Pb and Cd atomization in seawater samples in a rapidly heated (heating rate of 10 °C/msec) graphite furnace with ballast are studied. A method for determination of Pb and Cd in seawater samples using a Zeeman electrothermal atomic absorption (ETAA) spectrometer with tantalum ballast in a rapidly heated graphite furnace without preliminary sample preparation and/or addition of chemical modifiers is developed. The experiments were performed using seawater samples from the Baltic and Black Seas and a model seawater solution with a salinity of 35 g/liter. When the graphite furnace is heated, sample vapors condense on the relatively cold ballast, and then the sample repeatedly evaporates (re-evaporates) from the ballast, when it is heated by the radiation of the furnace walls, into a heated analytical cell. The shift of the atomization process to the region of steady-state and high furnace temperature and the decrease of background absorption during atomization help to decrease the chemical and matrix spectral effects on the analytical signal. To compensate the systematic error of element determination, the standard addition method adapted to the spectrometer conversion function was used. The analytical and metrological characteristics of the technique were established: characteristic masses of Pb — 2.2 pg, Cd — 0.17 pg and characteristic concentrations of Pb — 0.44 μg/liter, Cd — 0.034 μg/liter, detection limits of Pb — 0.20 μg/liter, Cd — 0.02 μg/liter, determination limits of Pb — 0.50 μg/liter, Cd — 0.05 μg/liter, random and systematic components of the error of determination of elements in seawater samples are no more than 10%.

1. Massmann H. Verleich von Atomabsorption und Atomfluoreszenz in der Graphiteküvette / Spectrochim. Acta, Part B. 1968. Vol. 23. No. 4. P. 215 – 226. DOI: 10.1016/0584-8547(68)80001-1

2. Katskov D. A., Grinshtein I. L. Reduction of Spectral Interference in Atomic Absorption Analysis in a Graphite Furnace with Ballast / Applied Spectroscopy. — Moscow, 1977. P. 147 – 149 [in Russian].

3. Katskov D. A., Grinshtein I. L. Atomization in a graphite furnace with ballast — a method for increasing the reliability of atomic absorption analysis / Zh. Prikl. Spektrosk. 1978. Vol. 28. No. 6. P. 968 – 974 [in Russian].

4. L’vov B. V., Pelieva L. A., Sharnopolsky A. I. Reducing the influence of the matrix in atomic absorption analysis of solutions in tubular furnaces by evaporating samples from a graphite substrate / Zh. Prikl. Spektrosk. 1977. Vol. 27. No. 3. P. 395 – 399 [in Russian].

5. Slavin W., Manning D. C., Carnrick G. R. The L’vov platform for furnace absorption analysis / Spectrochim. Acta, Part B. 1980. Vol. 35. Nos. 11 – 12. P. 701 – 714. DOI: 10.1016/0584-8547(80)80010-3

6. Welz B., Sperling M., Schlemmer G., et al. Spatially and temporally resolved gas phase temperature measurements in a Massmann-type graphite tube furnace using coherent anti-Stokes Raman scattering / Spectrochim. Acta, Part B. 1988. Vol. 43. P. 1187 – 1207. DOI: 10.1016/0584-8547(88)80163-0

7. Sperling M., Welz B., Hertzberg J., et al. Temporal and spatial temperature distributions in transversely heated graphite tube atomizers and their analytical characteristics for atomic absorption spectrometry / Spectrochim. Acta, Part B. 1996. Vol. 51. Nos. 9/10. P. 897 – 930. DOI: 10.1016/0584-8547(96)01520-0

8. Katskov D. A., Vasil’eva L. A., Grinshtein I. L., Savelyeva G. O. Atomic absorption analysis in a graphite furnace with a metal ballast-collector / Zh. Prikl. Spektrosk. 1987. Vol. 46. No. 4. P. 544 – 549 [in Russian].

9. Katskov D. A., Sadagov Yu. M., Banda M. Fast heated ballast furnace atomizer for atomic absorption spectrometry. Part 2. Experimental assessment of performances / J. Anal. At. Spectrom. 2005. Vol. 20. P. 227 – 232. DOI: 10.1039/b413345e

10. Katskov D. A. Fast heated ballast furnace atomizer for atomic absorption spectrometry. Part 1. Theoretical evaluation of atomization efficiency / J. Anal. At. Spectrom. 2005. Vol. 20. P. 220 – 226. DOI: 10.1039/b413342k

11. Sadagoff Yu. M. A longitudinally heated graphite furnace for a longitudinal magnetic field. Formation of absorbance signals / Spectrochim. Acta, Part B. 1997. Vol. 52. Nos. 9 – 10. P. 1395 – 1411. DOI: 10.1016/s0584-8547(97)00016-5

12. Sadagov Yu. M., Laptev S. A. Formation of analytical signals in graphite furnaces / J. Anal. Chem. 1998. Vol. 53. No. 10. P. 1051 – 1059 [in Russian].

13. Sadagov Yu. M., Batkov V. M., Furmansky E. A., Shinaev A. N. New Electrothermal Atomic Absorption Spectrometer: Technology and Analytics / Izm. Tekhnika. 2011. No. 9. P. 18 – 21 [in Russian].

14. Izrael Yu. A., Tsyban A. V. Anthropogenic Geology of the Ocean. — Leningrad: Gidrometeoizdat, 1989. — 528 p. [in Russian].

15. Horn R. Marine Chemistry. — Moscow: Mir, 1972. — 400 p. [Russian translation].

16. Alekin O. A., Lyakhin Yu. I. Chemistry of the Ocean. — Leningrad: Gidrometeoizdat, 1984. — 343 p. [in Russian].

17. Ershova T. S., Zaitsev V. F., Chaplygin V. A. Features of lead migration in the Caspian Sea ecosystem / Uch. Zap. Krym. Fed. Univ. im. V. I. Vernadskogo. Biol. Khim. 2021. Vol. 7. No. 4. P. 3 – 22 [in Russian].

18. Sharov A. N., Berezina N. A., Kupriyanov I., et al. Cadmium in the eastern gulf of Finland: Concentrations and effects on the mollusks Limecola baltica / Geochemistry. 2022. Vol. 67. No. 7. P. 702 – 710. DOI: 10.1134/s0016702922060076

19. Ermachenko L. A., Ermachenko V. M. Atomic absorption analysis with a graphite furnace. — Moscow: PAIMS, 1999. — 220 p. [in Russian].

20. Grotti M., Abelmochi M. L., Soggia F., Frache R. Determination of trace metals in sea-water by electrothermal atomic absorption spectrometry following solid-phase extraction: quantification and reduction of residual matrix effects / J. Anal. At. Spectrom. 2002. Vol. 17. P. 46 – 51. DOI: 10.1039/b108225f

21. Queroue F., Townsend A., van der Merve P., et al. Advances in the offline trace metal extraction of Mn, Co, Ni, Cu, Cd and Pb from open ocean seawater samples with determination by sector field ISP-MS analysis / Anal. Methods. 2014. Vol. 6. P. 2837 – 2847. DOI: 10.1039/c3ay41312h

22. Cabon J. Y. Determination of Cd and Pb in sea water by graphite furnace atomic absorption spectrometry with the use of hydrofluoric acid as a chemical modifier / Spectrochim. Acta, Part B. 2002. Vol. 57. No. 3. P. 513 – 524. DOI: 10.1016/s0584-8547(02)00005-8

23. Acar O. Determination of cadmium, copper and lead in soils, sediments and sea water samples by ETAAS using a Sc + Pd + NH4NO3 chemical modifier / Talanta. 2005. Vol. 65. No. 3. P. 672 – 677. DOI: 10.1016/j.talanta.2004.07.035

24. Sobolev N. A., Ivanchenko N. L., Kozhevnikov A. Yu. Direct determination of lead in sea water by high-resolution atomic absorption spectroscopy using a mixed modifier barium nitrate – hydrofluoric acid / J. Anal. Chem. 2019. Vol. 74. No. 5. P. 444 – 448. DOI: 10.1134/s1061934819020126

25. Sadagov Yu. M., Levin A. D., Biryukova I. V. Conversion functions in electrothermal atomic absorption spectrometry / Measurement technology. 2021. No. 4. P. 63 – 67 [in Russian]. DOI: 10.32446/0368-1025it.2021-4-63-67

26. Sadagov Yu. M., Tyutyunnik O. A., Kubrakova I. V., Sadagov A. Yu. Accounting of matrix effects in the spectrometric determination of trace elements using the single standard addition method / J. Anal. Chem. 2022. Vol. 77. No. 6. P. 727 – 732. DOI: 10.1134/s1061934822060144

27. Sadagov Yu. M., Sadagov A. Yu. Adaptive calibration in electrothermal atomic absorption spectrometry / J. Anal. Chem. 2023. Vol. 78. No. 8. P. 988 – 994. DOI: 10.1134/s1061934823080142

28. Doerffel K. Statistics in analytical chemistry. — Moscow: Mir, 1994. — 268 p. [Russian translation].

29. Tables of physical quantities: A handbook / I. K. Kikoin, Ed. — Moscow: Atomizdat, 1976. — 1006 p. [in Russian].