Multielement electrochemical vapor generation system coupled with atomic fluorescence spectrometer for simultaneous measurement of trace levels of As and Hg in coastal seawater samples

• Published in: Analytica chimica acta 2024-11, Vol.1330, p.343301, Article 343301
• Main Authors: Chen, Luodan, Wu, Rongkun, Xu, Biqing, Gong, Zhenbin, Yuan, Dongxing
• Format: Article
• Language: English
• Subjects: Electrochemical vapor generation; Multichannel atomic fluorescence spectrometer; Simultaneous determination; Ultra-trace As and Hg in seawater
• ISSN: 0003-2670; 1873-4324; 1873-4324
• DOI: 10.1016/j.aca.2024.343301

Toxic elements As and Hg in coastal waters affect human health through the food chain even at trace levels. The simultaneous determination of As and Hg in seawater using electrochemical vapor generation (ECVG) with atomic fluorescence spectrometer (AFS) currently has technical bottlenecks. One is the need for a simple and efficient chemical reaction cell and corresponding parameters to generate both AsH3 and Hg vapors, and the other is a suitable preservation method of the mixed standard solutions. A novel, efficient, online ECVG device was developed and interfaced with a laboratory-built multichannel AFS. The electrolytic cell adopted Sn–Pb alloy as the cathode material to generate both AsH3 and Hg vapors by electrolysis, replacing the unstable reagent tetrahydroborate (THB) usually used in most traditional vapor generation methods. The AFS was equipped with a built-in H2 generator for fuel supply, instead of the conventional acid-THB system. A mixed standard solution of As and Hg was prepared and preserved using thiourea-ascorbic acid as a fixing agent for Hg and a prereduction agent for As(V). The method detection limits (LOD, 3σ) were 0.005 and 0.003 μg/L for As and Hg, respectively. The relative standard deviations (RSD, n = 8) of the spiked samples were 2.8 % (0.50 μg/L As) and 3.1 % (0.05 μg/L Hg), respectively. The recoveries of standard spiked seawater samples with different salinities ranged from 86.1 % to 115.3 %. The system has been successfully applied to the simultaneous analysis of As and Hg in the seawater samples collected from the Xiamen coastal area. The study results provide a sensitive, accurate, and efficient method to promote the development and utilization of simultaneous analysis of multielement in seawaters. [Display omitted] •A system for As & Hg simultaneously electrochemical vapor generation.•Interfacing the electrolytic system with a multichannel atomic fluorescence spectrometer.•Preparation and preservation of low-concentration As and Hg mixed standard solutions.•Limits of detection at 0.005 and 0.003 μg/L for As and Hg, respectively.•Successful application of trace levels of As and Hg in coastal seawater.