Determination of arsenic in biological samples by slurry sampling hydride generation atomic fluorescence spectrometry using in situ dielectric barrier discharge trap

In this study, the slurry sampling hydride generation (SLS-HG) system was first coupled with in situ dielectric barrier discharge atomic fluorescence spectrometry (DBD-AFS) for arsenic analysis in biological samples based on the gas phase enrichment (GPE) principle. After a simple slurry dilution with 5% HCl (v/v) for microbiological and hair samples, the as-prepared slurry was introduced into the SLS-HG unit for arsine generation under 8 g L-1 KBH4 in 1.5 g L-1 KOH. Here, the in situ DBD apparatus, comprising of the three-concentric quartz tubes, was employed to pre-concentrate arsenic to enhance the analytical sensitivity of the HG-AFS, as well as to eliminate interferences due to the dilution effect and matrix separation. This was followed by trapping with 11 kV at 110 mL min(-1) of air carrier gas, and 190 s Ar gas sweeping, arsenic was released with 13 kV at 180 mL min(-1) H-2 to the AFS for measurement. Under optimal conditions, 8 pg or 14 pg detection limits (2 mL sampling) for the microbiological or hair samples were achieved without extra pre-concentration, respectively. The linearity R-2 was 0.996 ranging from 0.05 mg L-1 to 300 mg L-1. The spiked recoveries for the real paramecium and micro diatom samples were 93-102%, and the measurements were in accordance with the certified reference material (CRM) values. The proposed SLS-HG-in situ DBD-AFS method is extremely suitable for ultratrace arsenic determination in biological samples to protect human health and environmental safety.