水质.汞测定.使用浓缩和无浓缩的原子吸收光谱(AAS)方法

[中文适用范围]： 本国际标准规定了经过适当预消解后测定饮用水、地表水、地下水、雨水和废水中汞含量的两种方法。 对于第一种方法（第 6 条中描述），使用通过在例如金/铂吸附器上合并汞的富集步骤。 对于条款 7 中给出的方法，省略了富集步骤。 方法的选择取决于可用的设备、基质和感兴趣的浓度范围。 两种方法均适用于水中汞的测定。 富集方法（参见第 6 条）通常具有 0.01 µg/l 至 1 µg/l 的实际工作范围。 验证试验参与者报告的平均定量限 (LOQ)（参见附录 A）为 0.008 µg/l。 LOQ 上的信息为本国际标准的用户提供了方向，但不能取代基于实验室特定数据的性能数据估计。 必须考虑的是，使用特定仪器（例如单一汞分析仪）可以实现较低的 LOQ。 不加浓缩的方法（第 7 条中）通常具有从 0.05 µg/l 开始的实际工作范围。 验证试验参与者报告的 LOQ（见附录 A）为 0.024 µg/l。 用户可以根据具体应用来决定是否通过省略富集步骤和/或通过稀释样品来确定更高的浓度。 两种方法的灵敏度取决于所选的操作条件。 另一种无需预浓缩即可测定低至 0.002 µg/l 的极低汞浓度的可能性是应用原子荧光光谱法（参见 ISO 17852）。 特定的原子吸收汞分析仪无需预浓缩即可测定低至 0.010 µg/l 的浓度。 一般来说，通过 AAS（或 AFS）测定痕量汞浓度取决于实验室的清洁操作条件以及使用高纯度化学品和可忽略不计的低汞空白。 注：在适当的条件下进行额外的消化步骤并经过适当的方法验证后（见 7.4），本国际标准可适用于工业和城市废水。 必须彻底考虑厌氧还原工业废水的潜在样品稳定性问题（汞损失）。 [外文原描述]： ISO 12846:2012 specifies two methods for the determination of mercury in drinking, surface, ground, rain and waste water after appropriate pre-digestion. For the first method, an enrichment step by amalgamation of the Hg on, for example, a gold/platinum adsorber is used. For the second method, the enrichment step is omitted. The choice of method depends on the equipment available, the matrix and the concentration range of interest. Both methods are suitable for the determination of mercury in water. The method with enrichment commonly has a practical working range from 0,01 µg/l to 1 µg/l. The mean limit of quantification (LOQ) reported by the participants of the validation trial was 0,008 µg/l. This information on the LOQ gives the user of ISO 12846:2012 an orientation and does not replace the estimation of performance data from laboratory specific data. It has to be considered that it is possible to achieve lower LOQs with specific instrumentation (e.g. single mercury analysers). The method without enrichment commonly has a practical working range starting at 0,05 µg/l. The LOQ reported by the participants of the validation trial was 0,024 µg/l. It is up to the user, based on the specific application, to decide whether higher concentrations are determined by omitting the enrichment step and/or by diluting the sample(s). The sensitivity of both methods is dependent on the selected operating conditions. Another possibility for the determination of extremely low Hg concentrations down to 0,002 µg/l without pre-concentration is the application of atomic fluorescence spectrometry (see ISO 17852). Specific atomic-absorption mercury analysers allow determinations down to 0,010 µg/l without pre-concentration. In general, the determination of trace concentrations of Hg by AAS (or AFS) is dependent on clean operating conditions in the laboratory and on the use of high-purity chemicals with negligible low-Hg blanks. Note that ISO 12846:2012 may be applied to industrial and municipal waste water after an additional digestion step performed under appropriate conditions and after suitable method validation. A potential sample stability issue (mercury loss) for anaerobic reducing industrial effluents has to be considered thoroughly.