Development of a MSFIA system for sequential determination of antimony, arsenic and selenium using hydride generation atomic fluorescence spectrometry

Abstract

This paper proposed a multisyringe flow injection analysis (MSFIA) system for antimony, arsenic and selenium determination in peanut samples by hydride generation atomic fluorescence spectrometry (HG-AFS). The optimization step of the hydride generation was performed using a two-level full factorial design involving the parameters: hydrochloric acid, sodium tetrahydroborate and potassium iodide concentrations. So, using the chemical conditions optimized, this method allows the determination of these elements employing the external calibration technique using aqueous standards with limits of detection and quantification of 0.04 and 0.14µgL−1 for antimony, 0.04 and 0.14µgL−1 for arsenic and 0.14 and 0.37µgL−1 for selenium, respectively. Additionally, the effect of vanadium, chromium, cobalt, nickel, zinc, copper, iron and molybdenum on the generation of chemical vapour was also studied. The precision expressed as relative standard deviation varied from 1.2 to 3.6% for antimony, 1.8–3.9% for arsenic and 1.8–2% for selenium. The accuracy for arsenic and selenium was confirmed using the certified peach leaves reference material SRM 1547 produced by National Institute of Standard and Technology. The proposed method showed 45 injection throughput (h−1) using 1.6mL sample volume for each element, 0.8mL NaBH4 0.5% (w/v) containing NaOH 0.05% (w/v), 0.8mL HCl 5M and 0.4mL KI 14% (w/v) containing L-ascorbic acid 2.5% (w/v). The method was applied to the determination of antimony, arsenic and selenium in peanut samples, which were firstly lyophilized and afterward digested using microwave assisted radiation. Six samples were analyzed and the contents of the elements found were: 28.7–41.3µgkg−1 for arsenic, 86.4–480.1µgkg−1 for selenium and 32.6–52.4µgkg−1 for antimony. Addition/recovery tests were also performed to confirm the method accuracy for the three elements.