Determination of carbon in steel by laser-induced breakdown spectroscopy using a microchip laser and miniature...

Laser-induced breakdown spectroscopy using a microchip laser and a miniature spectrometer has been applied to the determination of carbon in steel. The goal was to investigate the capability of an apparatus, made up of commercial components, that could form the basis of a handheld device. The typical precision obtained in the range of C/Fe weight ratios of 0.001 to 0.01 was 4.3%, and the limit of detection was a C/Fe ratio of 400 ppm. This is higher than values reported for conventional systems and is primarily determined by systematic variations in the spectra and not by signal intensity levels. These systematic variations are ascribed to two causes: the use of an ungated detector and the spatial variability of the emission plume.