A fast and robust direct solid sampling method for the determination of 27 trace, main and minor elements in soda-lime glass based on ETV-ICP OES and using a gaseous halogenating modifier

A method, based on electrothermal vaporization (ETV) coupled to inductively coupled plasma optical emission spectrometry (ICP OES), has been optimized for direct solid sampling analysis of soda-lime glass—the most common type of industrially manufactured glass. This method allows fast and reliable quantification of the main elements—Al, Ca, K, Mg, Na, and Si—and trace elements—As, Ba, Cd, Ce, Co, Cr, Cu, Fe, Mn, Mo, Ni, (P), Pb, Sb, (Se), Sn, Sr, Ti, V, Zn, and Zr. In the presented ETV-ICP OES method, calibration is performed predominantly with matrix-free synthetic samples. This metrological advantage is normally not achieved with direct solid sampling methods and is one of the goals of the present study. In a certification interlaboratory comparison for the soda-lime glass CRM BAM-S005c, 2 out of 16 laboratories employed the ETV-ICP OES method. An improved analytical performance was obtained compared with the results of laboratories that used conventional liquid ICP OES. For both methods, the average relative deviations between the laboratory results and certified values as well as the average values of relative standard deviation were with a few exceptions <10%, in most cases even <5%, which indicated high trueness and precision. The limits of quantification of the trace elements by ETV-ICP OES were mostly <3 mg kg−1. Low subsample masses of 0.2–0.6 mg were used to avoid matrix effects. The optimized conditions consist of using CHF3 as a modifier gas at a flow rate of 2.3 mL min−1, an ETV temperature program with a final temperature of 2530 °C, and use of graphite grit material in combination with a sample boat with a hemispherical cavity for the optimal release of the analytes.