A novel method of ultraviolet vapour generation (UVG) coupled with atomic fluorescence spectrometry (AFS) was developed for the determination of ultratrace inorganic arsenic (iAs) in surface water. In this work, different ferric species were utilised for the first time as an enhancement reagent for the ultraviolet vapour generation of As(III), and their UVG efficiencies for volatile species of arsenic were investigated. 15 mg L⁻¹ of ferric chloride provided the greatest enhancement of approximately 10-fold, using 20% acetic acid combined with 4% formic acid with 30 s ultraviolet irradiation at 200 mL min⁻¹ Ar/H₂ flow rate. Under the optimised conditions, the linear range was 1.0 μg L⁻¹–100.0 μg L⁻¹, and the spiked recoveries were 92%–98%. The limit of detection was 0.05 μg L⁻¹ for iAs, and the relative standard deviation (RSD) value of the repeated measurements was 2.0% (n = 11). This method was successfully applied to the determination of ultratrace iAs in tap water, river water, and lake water samples using 0.2% H₂SO₄ (v : v) as the sample preserver. The obtained values for the water samples of certified reference materials (CRMs) including GSB-Z50004-200431, GBW08605 and GBW(E)080390 were all within the certified ranges.

On the basis of the vaporization temperature difference principle between Hg and Cd analytes, a novel solid sampling system coupled with atomic fluorescence spectrometry (AFS) was developed for the sequential determination of trace Hg and Cd in food samples. The solid sampling system mainly comprised a gold coil trap for Hg and a tungsten coil (TC) trap for Cd to eliminate matrix interference, and an on-line Ni–Cr heating coil as the Hg electrothermal vaporizer (ETV) as well as a sample ashing furnace, and a porous carbon tube as the Cd ETV. These units were connected by a modified gas line system integrating air and Ar/H₂ (v/v = 9 : 1). The optimal vaporization (500–600 °C), trapping (ambient temperature), and pre-heating conditions of the gold coil (800 °C for 14–16 s) for Hg were all investigated, as well as the sample ashing (the same as Hg vaporization), vaporization (1200 °C for 20 s), and releasing (2000 °C for 1 s) conditions for Cd at 600 mL min⁻¹ of both air and Ar/H₂ carrier gases. Under the optimum conditions, the detection limits (LODs) could reach 0.7 pg for Hg and 0.5 pg for Cd with less than 15% relative standard deviations (RSDs), namely 0.07 μg kg⁻¹ and 0.05 μg kg⁻¹ when introducing 10 mg sample mass, respectively. Furthermore, the spiked recoveries were 95.0–115.0% for Hg and 84.0–113.0% for Cd. The Hg and Cd concentrations measured by the proposed solid sampling method were all consistent with the certified reference material (CRM) values and those obtained by microwave digestion inductively coupled plasma mass spectrometry. The solid sampling Hg–Cd analyzer was extremely suitable for the in-field, rapid and accurate monitoring of Hg and Cd in food samples.

A two-stage diameter-varied quartz tube (QT) consisting of a QT electrothermal vapourizer, a quartz tube atom trap (QTAT) and two separate Ni–Cr electrical heating coils was interfaced with atomic fluorescence spectrometry (AFS). This is the first time that an atom trap is employed to trap Pb using electrothermal vapourization (ETV) as a solid sampling approach. The optimum ashing, vapourization, trapping, and releasing procedures and carrier gas were investigated. Under the optimized conditions, Pb in the ashed sample residues was vapourized at 850 °C, followed by analyte separation from the matrix with a 400 mL min⁻¹ carrier gas of 10% H₂/Ar (v/v) mixture through trapping Pb on the inner surface of the QTAT without heating. Finally, Pb was released from the QTAT by heating to 800 °C with the carrier gas switch-off and was then swept by the carrier gas into the AFS for measurement. The method LOD and the RSD of repeated measurements were 2 pg and 1.5%, respectively, indicating sufficient analytical sensitivity and precision. The Pb concentrations measured in reference materials by the proposed QT-ETV-QTAT-AFS method were within the certified values, and the spiked recoveries ranged from 95% to 106%, which demonstrated satisfactory accuracy for rapid and on-site determination of Pb in food samples. Furthermore, the vapourization, trapping and releasing mechanisms for Pb by QT-ETV-QTAT-AFS were also studied via tungsten coil ETV-QTAT-AFS, in situ atomic absorption spectrometry, X-ray photoelectron spectroscopy and other means. We deduced that the formation of atom clusters played a crucial role in Pb transportation to the detector.

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 H₂ 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 R² was 0.996 ranging from 0.05 μg L⁻¹ to 300 μg 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.