Application of laser-induced break down spectroscopy (LIBS) for detection of trace elements in metal alloys and rock samples

Time-resolved laser-induced breakdown spectroscopy with the used of a pulsed Nd : YAG laser (355 nm, 10 Hz) has been developed and applied for quantitative elemental analysis of zinc-base alloys and rock samples. The breakdown occurred at the sample surface by a pulsed Nd : YAG laser under 1 atmospheric pressure of helium or reduced pressure of argon. The analytical signals were integrated within 2.0 μs at an optimum delay time of gate (200 ns) which was derived from the evaluation of temporal behavior in emission signal. Visible emission from excited species in laser-induced plasma is monitored by the use of a gated-ICCD detection system. Calibration curves of various elements including Mg, Cu, Cr, Si, Ca were obtained on the absolute concentration scale. The detection limit (signal-to-noise ratio=3) are element-dependent and varied with complexity in sample composition but are on the order of 5-100 ppm. Precision is typically 5 to 10%.