Determination of As, Se, and Hg in fuel samples by in-chamber chemical vapor generation ICP OES using a Flow Blurring® multinebulizer

Abstract

In this work, a new and simple analytical methodology based on in-chamber chemical vapor generation has been developed for the spectrochemical analysis of commercial fuel samples. A multiple nebulizer with three nebulization units has been employed for this purpose: One unit was used for sample introduction, while the other two were used for the necessary reagent introduction. In this way, the aerosols were mixed inside the spray chamber. Through this method, analyte transport and, therefore, sensitivity are improved in inductively coupled plasma-optical emission spectrometry. The factors (i.e., variables), influencing chemical vapor generation, have been optimized using a multivariate approach. Under optimum chemical vapor generation conditions ([NaBH4] = 1.39%, [HCl] = 2.97 M, total liquid flow = 936 μL min−1), the proposed sample introduction system allowed the determination of arsenic, selenium, and mercury up to 5 μg g−1 with a limit of detection of 25, 140, and 13 μg kg−1, respectively. Analyzing spiked commercial fuel samples, recovery values obtained were between 96 and 113%, and expanded uncertainty values ranged from 4 to 16%. The most striking practical conclusion of this investigation is that no carbon deposit appears on the plasma torch after extended periods of working.