Direct speciation of Cr in drinking water by in situ thermal separation ETAAS.
Direct speciation of Cr in drinking water by in situ thermal separation ETAAS.
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DOI：
10.1039/c6ay03223k
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发表时间：
2017-02
影响因子：
3.1
通讯作者：
Hao Cui;Wei Guo;Lanlan Jin;Q. Guo;Shenghong Hu
中科院分区：
文献类型：
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作者：
Hao Cui;Wei Guo;Lanlan Jin;Q. Guo;Shenghong Hu
现已开发出基于热分离和电热原子吸收光谱 (ETAAS) 检测的 Cr(VI) 和 Cr(III) 的原位形态分析方法。采用络合剂2-噻吩甲酰三氟丙酮(TTA)与Cr(III)选择性反应； Cr(III)-TTA 络合物的产物在 400 °C 时蒸发，而 Cr(VI) 定量地保持在 1200 °C 的温度，随后被 AAS 检测到。使用电喷雾电离高分辨率四极杆 Orbitrap 质谱 (ESI-HR-MS) 验证了挥发性 Cr-TTA 络合物的络合反应产物。 Cr(III) 浓度是通过计算总 Cr (Cr(T)) 和 Cr(VI) 浓度之间的差值确定的。在最佳实验条件下，Cr(VI)和Cr(T)的检出限分别为0.046 μg L−1和0.039 μg L−1，1.0 μg L−1 Cr(VI)和1.0 μg L−1 Cr(T)的RSD分别为3.1%和2.8% (n = 5)。通过测试两种水标准参考物质 (SRM) 的总铬含量，验证了该方法的准确性。所提出的方法用于饮用水的分析。自来水、瓶装水和井水的 Cr(VI) 浓度分别为 1.41、0.53 和 0.68 μg L−1，与离子色谱 ICP-MS 测量的参考值非常一致。这种高通量方法在筛查饮用水中超痕量铬形态方面具有巨大潜力。
In situ speciation of Cr(VI) and Cr(III) based on thermal separation and electrothermal atomic absorption spectrometry (ETAAS) detection has been developed. The complexant 2-thenoyltrifluoracetone (TTA) was used to selectively react with Cr(III); the product of the Cr(III)–TTA complex vaporized at 400 °C, while Cr(VI) quantitatively remains up to a temperature of 1200 °C and was subsequently detected by AAS. The complexation reaction products of the volatile Cr–TTA complex were verified using electro-spray ionization high resolution quadrupole-Orbitrap-mass spectrometry (ESI-HR-MS). The Cr(III) concentration was established by calculating the difference between the total Cr (Cr(T)) and Cr(VI) concentrations. Under optimum experimental conditions, the detection limits for Cr(VI) and Cr(T) are 0.046 μg L−1 and 0.039 μg L−1, with RSDs for 1.0 μg L−1 of Cr(VI) and 1.0 μg L−1 of Cr(T) of 3.1% and 2.8% (n = 5), respectively. The accuracy of this method was validated by testing two water standard reference materials (SRMs) for total chromium. The proposed method was employed for analysis of drinking water. The Cr(VI) concentrations for tap water, bottled water, and well water were found to be 1.41, 0.53 and 0.68 μg L−1, respectively, which is in good agreement with the reference values measured by ion chromatographic ICP-MS. This high throughput method has great potential for screening of Cr species at ultra-trace levels in drinking water.