Plasma diagnostics and determination of lead in soil and Phaleria Macrocarpa leaves by ungated laser induced breakdown spectroscopy

Abstract

Laser induced breakdown spectroscopy (LIBS) is an excellent technique that may be more convenient and less expensive by the elimination of the time gating operation. In this study, ungated single pulse LIBS was explored for the determination of lead in leaves and soil at various ambient air pressures. Ground Phaleria Macrocarpa and soil were utilized for this investigation. Matrix matched, laboratory prepared calibration samples were ablated with a Nd:YAG (1064 nm, 100 mJ, 10 ns) laser and spectra were recorded using a spectrometer equipped with a CCD detector. The pressure was optimized for the highest signal-to-noise ratio and moderate background signal. Calibration curves were drawn at the optimized ambient pressure of 500 mbar. Linear calibration curves were obtained with regression coefficients exceeding 0.98 using the lead I 363.95 nm line. The maximum relative errors in lead concentrations were 10.69% and 18.59% from Phaleria Macrocarpa and soil, respectively. Relative standard deviations of 14.99% and 3.42 were obtained for lead in Phaleria Macrocarpa and soil. The results demonstrate that ungated LIBS may be used for the determination of lead in leaves and soil with reasonable accuracy.