FUNDAMENTAL-STUDIES OF LASER ABLATION FOR THE INTRODUCTION OF POWDERED SOLID SAMPLES INTO AN INDUCTIVELY COUPLED PLASMA

Pelletized pond sediment was ablated by a pulsed Nd:YAG laser (0.35 J). The ablated material was swept into an inductively coupled plasma (ICP), and the emission spectra were measured by using a photodiode-array-based spectrometer. The mass transport efficiency was 35, 31, 25, and 21% for transport tubes that were 1.8, 3.2, 6, and 10 m long. With the use of a transport tube of 6 m, the pulse-to-pulse variation of the Mg(II) emission intensities at 279.6 and 280.3 nm was approximately 30% as a relative standard deviation (RSD) of 12 measurements. It was found that the emission intensities were linearly related to the amount ablated. The precision for the Mg signals was improved to about 4%, if a steady-state signal was maintained by translation of the sample during repetitive shots of the laser and if Fe was used as an internal standard.