QUANTITATIVE ANALYSIS OF MAGNESIUM IN SOIL BY LASER-INDUCED BREAKDOWN SPECTROSCOPY COUPLED WITH NONLINEAR MULTIVARIATE CALIBRATION

Laser-induced breakdown spectroscopy (LIBS) coupled with the nonlinear multivariate regression method was applied to analyze magnesium (Mg) contents in soil. The plasma was generated using a 100 mJ Nd:YAG pulsed laser, and the spectra were acquired using a multi-channel spectrometer integrated with a CCD detector. The line at 383.8 nm was selected as the analysis line for Mg. The calibration model between the intensity of characteristic line and the concentration of Mg was constructed. The traditional calibration curve showed that the concentration of Mg was not only related to the line intensity of itself, but also to other elements in soil. The intensity of characteristic lines for Mg (Mg I 383.8 nm), manganese (Mn) (Mn I 403.1 nm), and iron (Fe) (Fe I 407.2 nm) were used as input data for nonlinear multivariate calculation. According to the results of nonlinear regression, the ternary nonlinear regression was the most appropriate of the studied models. A good agreement was observed between the actual concentration provided by inductively coupled plasma mass spectrometry (ICP-MS) and the predicted value obtained using the nonlinear multivariate regression model. The correlation coefficient between predicted concentration and the measured value was 0.987, while the root mean square error of calibration (RMSEC) and root mean square error of prediction (RMSEP) were reduced to 0.017% and 0.014%, respectively. The ratio of the standard deviation of the validation to the RMSEP increased to 8.79, and the relative error was below 1.21% for nine validation samples. This indicated that the multivariate model can obtain better predicted accuracy than the calibration curve. These results also suggest that the LIBS technique is a powerful tool for analyzing the micro-nutrient elements in soil by selecting calibration and validation samples with similar matrix composition.

лазерно-искровая спектроскопия, почва, магний, нелинейная многопараметрическая калибровка, laser-induced breakdown spectroscopy, soil, magnesium, nonlinear multivariate calibration

1. D. A. Cremers, L. J. Radziemski, Handbook of Laser-Induced Breakdown Spectroscopy, Wiley (2013).

2. R. Noll, Laser-Induced Breakdown Spectroscopy (LIBS): Fundamentals and Aapplications, Springer (2012).

3. Madhavi Martin, Rodger C. Martin, Steve Allman, Deanne Brice, Ann Wymore, Nicolas Andre, Spectrochim. Acta B, 114, 65 (2015).

4. E. Negre,V. Motto-Ros, F. Pelascini, S. Lauper, D. Denis, Jin Yu, J. Anal. At. Spectrom., 30, 417 (2015).

5. Tran X. Phuoc, Ping Wang, Dustin McIntyre, Fuel, 163, 129 (2016).

6. F. J. Fortes, M. D. Perez-Carceles, A. Sibon, A. Luna, J. Javier Laserna, Int. J. Legal Med., 129, 807 (2015).

7. M. A. Aguirre, E. J. Selva, M. Hidalgo, A. Canals, Talanta, 131, 348 (2015).

8. M. A. Gondal, M. A. Shemis, A. A. I. Khalil, M. M. Nasr, B. Gondal, J. Anal. Atom Spectrom., 31, 506 (2016).

9. D. Diaz, D. W. Hahn, A. Molina, Appl. Spectrosc., 66, 99 (2012).

10. F. C. Alviraa, G. M. Bilmes, T. Floresc, L. Ponce, Appl. Spectrosc., 69, 1205 (2015).

11. B. S. Marangoni, K. S. G. Silva, G. Nicolodelli, G. S. Senesi, J. S. Cabral, P. R. Villas-Boas, C. S. Silva, P. C. Teixeira, A. R. A. Nogueira, V. M. Benitesf, D. M. B. P. Milori, Anal. Methods, 8, 78 (2016). 674-8

12. Krishna K. Ayyalasomayajula, Fang Yu-Yueh, Jagdish P. Singh, Dustin L.McIntyre, Jinesh Jain, Appl. Opt., 51, B149 (2012).

13. R. S. Bricklemyer, D. J. Brown, J. E. Barefield, S. M. Clegg, Soil Sci. Soc. Am. J., 75, 1006 (2001).

14. D. M. Dong, C. J. Zhao, W. G. Zheng, X. D. Zhao, L. Z. Jiao, Spectrosc Lett., 46, 421 (2013).

15. Cuiping Lu, Liusan Wang, Haiying Hu, Zhong Zhuang, Yubing Wang, Rujing Wang, Liangtu Song, Chin Opt Lett., 11, 053004 (2013).

16. P. R. Villas-Boas, R. Arnon Romano, M. A. de Menezes Franco, E. C. Ferreira, E. José Ferreira, S. Crestana, D. Marcondes Bastos Pereira Milori, Geoderma, 263, 195 (2016).

17. Wang Shaolong, Wang Yangen, Chen Shanjun, Chen Qi, Plasma Sci. Technol., 17, 716 (2016).

18. W. Tawfik, W. A. Farooq, F. N. Al-Mutairi, Z. A. Alahmed, Laser Eng., 32, 129 (2015).

19. T. F. Boucher, M. V. Ozanne, M. L. Carmosino, M. Darby Dyar, S. Mahadevan, E. A. Breves, K. H. Lepore, S. M. Clegg, Spectrochim. Acta B, 107, 1 (2015).

20. D. L. Death, A. P. Cunningham, L. J. Pollard, Spectrochim. Acta B, 63, 763 (2008).

21. M. D. Dyar, M. L. Carmosino, E. A. Breves, M. V. Ozanne, S. M. Clegg, R. C. Wiens, Spectrochim. Acta B, 70, 51 (2012).

22. S. Laville, M. Sabsabi, F. R. Doucet, Spectrochim. Acta B, 62, 1557 (2007).

23. Feng, L. Li, W. Ni, Z. Li, J. Anal. At. Spectrom., 26, 2289 (2011).