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•New insight to explain the relationship between KBD and water environment.•The pathogenesis of KBD is unrelated to the groundwater.•The ion sources of groundwater in KBD areas are mainly affected by rock weathering.

Photochemical vapor generation (PVG) has emerged as a promising sample introduction method for atomic spectrometry in recent years. Despite its great success, a major impediment for the wide application of PVG is the interferences from the coexisting ions, especially transition-metal ions. In this work, iron and 1,3,5-benzenetricarboxylic (Fe-BTC), a Fe-containing metal–organic framework (MOF) material, was synthesized and first used as a platform integrating the sample matrix separation, preconcentration, and photocatalysis for the highly selective determination of elements by PVG. Bismuth was selected as a model analyte. Fe-BTC served not only as the photocatalyst for the PVG of Bi3+but also as an efficient absorbent for the separation of analytes from the sample matrix. Compared with the previous PVG system, the performance of tolerating interferences toward coexisting ions of the proposed method has been greatly improved after using Fe-BTC-based matrix separation. Thus the excess of 10 mg L–1of Co2+and 100 mg L–1of Cu2+, Ni2+, and Fe3+caused no obvious interferences for 1 μg L–1of Bi determination. Under the optimal conditions, the limit of detection (LOD, 3σ) of the developed method was 0.3 ng L–1with the inductively coupled plasma–mass spectrometry (ICPMS) measurement, which could be lowered down to 0.04 ng L–1after ten times of preconcentration with Fe-BTC prior to analysis. This method was successfully applied for the analysis of Bi in complicated sample matrices of soil (GBW07401), sediment (GBW07310), nickel–iron alloy (GBW01622), and nickel alloys (GBW01641) by the external calibration method.

An enhanced photochemical vapor generation (PVG) sample introduction procedure is developed for the determination of trace Bi with inductively coupled plasma mass spectrometry (ICP MS) by the addition of iron. Gas chromatography mass spectrometry (GC–MS) reveals that (CH3)3Bi is the major component of the volatile Bi species formed in the presence of 20% (v/v) acetic acid, 5% (v/v) formic acid, and 60 μg mL–1Fe3+under UV irradiation. The addition of Fe3+not only largely increases the PVG efficiency of Bi3+but also accelerates the reaction kinetics of photochemical reduction of Bi3+. The analytical sensitivity was enhanced 30-fold using PVG for sample introduction compared to that for direct solution nebulization detection by ICP MS detection. Furthermore, the proposed method shows much better tolerance of interference from Cu2+and Ni2+than that from conventional hydride generation (HG). Under the optimized conditions, a detection limit of 0.3 ng L–1was obtained for Bi by ICP MS determination. The relative standard deviation (RSD) was 2.5% for seven replicate measurements of 0.5 ng mL–1Bi3+standard solution. The proposed method has been successfully applied for the determination of Bi in environmental samples, including water samples, and certified reference material of soil (GSS-1) and sediments (GSD-5a and GSD-10) with satisfying results.