Use of Internal Standardization to Compensate for a Wide Range of Absorbance in the Analysis of Glasses by UV Laser Ablation Inductively Coupled Plasma Atomic Emission Spectrometry

Abstract

A frequency-tripled Q-switched Nd:YAG laser (355 nm, 10 Hz, 5 mJ per shot, Surelite, Continuum) was used for the ablation of glasses as direct solid sampling for inductively coupled plasma atomic emission spectrometric multichannel detection. The colored and transparent glasses were glass standards used for calibration in X-ray fluorescence spectrometry and exhibited a 0.15–3.5 absorbance range at 355 nm. Translation of the target (1 mm s⁻¹) with respect to the laser beam was used over a length of 16 mm. The depths and widths of the corresponding patterns were not related to the absorbance of the samples. However, the analytical line intensities were efficiently compensated for by using the Si(I) 251.611 nm line as an internal standard. The repeatability was therefore improved for Na, K, Ca, Mg, Sr, Ba, Zn, Pb, Al, Fe, and Sb, as well as the correlation coefficients of the regression and the centroid uncertainties of the calibration graph. Preliminary investigations were carried out to evaluate the acoustic signal emitted by the microplasma as external standardization. However, a negative correlation was found with the line intensity signals under our operating conditions.