Institute of Analytical Chemistry of the CAS , v. v. i., Veveří 97, 602 00 Brno, Czech Republic.
Charles University in Prague , Faculty of Science, Department of Analytical Chemistry, Albertov 6, 128 43 Prague, Czech Republic.
Anal Chem. 2016 Apr 5;88(7):4041-7. doi: 10.1021/acs.analchem.6b00370. Epub 2016 Mar 14.
An experimental setup consisting of a flow injection hydride generator coupled to an atomic fluorescence spectrometer was optimized in order to generate arsanes from tri- and pentavalent inorganic arsenic species (iAs(III), iAs(V)), monomethylarsonic acid (MAs(V)), and dimethylarsinic acid (DMAs(V)) with 100% efficiency with the use of only HCl and NaBH4 as the reagents. The optimal concentration of HCl was 2 mol L(-1); the optimal concentration of NaBH4 was 2.5% (m/v), and the volume of the reaction coil was 8.9 mL. To prevent excessive signal noise due to fluctuations of hydride supply to an atomizer, a new design of a gas-liquid separator was implemented. The optimized experimental setup was subsequently interfaced to HPLC and employed for speciation analysis of arsenic. Two chromatography columns were tested: (i) ion-pair chromatography and (ii) ion exchange chromatography. The latter offered much better results for human urine samples without a need for sample dilution. Due to the equal hydride generation efficiency (and thus the sensitivities) of all As species, a single species standardization by DMAs(V) standard was feasible. The limits of detection for iAs(III), iAs(V), MAs(V), and DMAs(V) were 40, 97, 57, and 55 pg mL(-1), respectively. Accuracy of the method was tested by the analysis of the standard reference material (human urine NIST 2669), and the method was also verified by the comparative analyses of human urine samples collected from five individuals with an independent reference method.
建立了一个流动注射氢化物发生原子荧光光谱联用系统，用于将三价和五价无机砷（iAs(III)、iAs(V)）、一甲基砷酸（MAs(V)）和二甲基砷酸（DMAs(V)）完全转化为胂，仅使用 HCl 和 NaBH4 作为试剂。HCl 的最佳浓度为 2 mol/L；NaBH4 的最佳浓度为 2.5%（m/v），反应盘管的体积为 8.9 mL。为防止由于供氢到原子化器的波动而导致信号噪声过大，采用了一种新的气液分离器设计。优化后的实验装置随后与 HPLC 接口，用于砷的形态分析。测试了两种色谱柱：（i）离子对色谱法和（ii）离子交换色谱法。后者对于未经稀释的人尿样提供了更好的结果。由于所有 As 形态的氢化物生成效率（因此灵敏度）相等，因此可以通过 DMAs(V)标准品对单一形态进行标准化。iAs(III)、iAs(V)、MAs(V)和 DMAs(V)的检出限分别为 40、97、57 和 55 pg/mL。通过对标准参考物质（NIST 2669 人尿）的分析测试了该方法的准确性，并通过与独立参考方法收集的五个人的人尿样本的比较分析验证了该方法。
