Abstract:

Objective To compare the impact of different pre-treatment methods on the detection of arsenic in water with complex matrices，screen for the optimal method that ensures normal peak shape and retention time，and verify this through proficiency testing. Methods Referring to GB/T 5750.6-2023 "standard examination methods for drinking water-Part 6：Metal and metalloid indices" 9.1，hydride generation atomic fluorescence spectrometry was used to determine arsenic in water. The sample solution was diluted to 5 times with pure water，5% hydrochloric acid，and the 125 g/L thiourea-ascorbic acid solution，heated at 70 ℃ for 30 min，and then detected by atomic fluorescence spectrophotometry. Results Within the linear range of 0-20 μg/L，the standard curve was I=90.927 4×C-13.638 7，with a correlation coefficient of 0.999 7. Quality control was performed on the samples using spike recovery and the reference sample，and the proficiency testing result was satisfactory. Conclusion Through this proficiency testing，the laboratory personnel optimize the pre-treatment steps for complex matrix water samples，enhance the accuracy of arsenic detection，and provide an effective pre-treatment method for the detection of arsenic in complex water samples.

Key words: Arsenic, Atomic fluorescence spectrometry, Water matrix, Proficiency testing, Influencing factors