| Oil paints are used on many light industrial products. The concentration of heavy metals in paints is one of critical standards for quality control of the products and their safeties for use. First, laser induced breakdown spectroscopy (LIBS) is applied to rapid quantitative analysis of Pb, Cr, Cd, Hg in the oil paint in this study. By observing atomic emission intensities from paints samples, the concentrations of heavy metals can be qualitatively estimated. A quantitative analysis can be realized by using external standard method, while the calibration curves are determined using a few reference samples in which the concentrations of heavy metals are known and are measured under the same experimental condition. The limits of detection of Pb, Cr, Cd, Hg were determined to be 9, 3.5, 23, 998.91μg/g with LIBS, respectively.As the result of the sensitivity of Hg is poor, an advanced analytical method called optical-electric dual pulse LIBS (OEDP-LIBS) was developed. In this method, a high voltage pulse generator was added to assist LIBS. The atomic emission of Hg at 253.65nm which faded in several microseconds would be excited again by high-voltage arc, while the signal of background at 253.2nm was not enhanced. So we can get very high Signal to Noise Ratio (SNR) by selecting appropriate gate of data acquisition. In this experiment, the calibration curve and the limit of detection of 11.6μg/g of Hg in yellow oil paint has been obtained. The limit of detection Pb, Cr, Cd with LIBS and Hg with OEDP-LIBS in the oil paint are less than the maximum limitation of ASTM F963(USA) and EN71(EU). Relative measure error is less than 10% and the time required for single measurement is 2 minutes with LIBS and 5 minutes with OEDP-LIBS. All experiments were carried out in ambient environment.
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