ISO/TS 19620:2018规定了一种主要用于在饮用水、自来水、地表水、地下水和雨水等总有机碳含量较低的水中保存后，测定样品中溶解的无机砷物种（亚砷酸盐（As（III））和砷酸盐（As（V））的方法。提供了有关测定天然地表水中可能遇到的潜在相关有机砷物种的信息，如甲基胂酸（MMA）和二甲基胂酸（DMA）。 线性工作动态范围取决于工作条件和使用的检测方法；在标准条件下，每个物种的浓度通常在0.5μg/l到50μg/l之间。 在适当稀释后，可分析浓度高于线性动态范围的含砷样品。 该方法基于高效液相色谱法分离砷物种，使用电感耦合质谱（ICP-MS）或氢化物发生原子荧光光谱法（HG-AFS）作为检测方法。 该方法的灵敏度取决于检测方法和选择的仪器操作条件。该方法的定量限（LOQ）还取决于所用分析系统的操作条件和所用校准范围的范围。提供了As（III）和As（V）的LOQ示例； 定量限通常小于1μg/l。 ISO/TS 19620:2018不适用于天然水样中不存在的砷甜菜碱和其他有机砷物种。

ISO/TS 19620:2018 specifies a method primarily developed for the determination of inorganic arsenic species (arsenite (As(III)) and arsenate (As(V)) dissolved in a sample after a preservation process in waters with a low total organic carbon content such as potable water, tap water, surface waters, ground waters and rain waters. Information is provided on the determination of potentially relevant organo-arsenic species such as methylarsonic acid (MMA) and dimethylarsinic acid (DMA) which may be encountered at very low levels in natural surface waters. The linear working dynamic range depends on the operating conditions and the method of detection used; under standard conditions, it typically ranges from 0,5 μg/l to 50 μg/l for each species. Samples containing arsenic at concentrations higher than the linear dynamic range can be analysed after suitable dilution. This method is based on high performance liquid chromatography separation of arsenic species with either inductively coupled mass spectrometry (ICP-MS) or hydride generation atomic fluorescence spectrometry (HG-AFS) as a method of detection. The sensitivity of this method depends on the method of detection and the instrumental operating conditions selected. The limit of quantification (LOQ) of the method also depends on the operating conditions of the analytical system used and the extent of the calibration range used. LOQ examples for As(III) and As(V) are provided; LOQs are generally less than 1 μg/l. ISO/TS 19620:2018 does not apply to arsenobetaine and other organic arsenic species which are not present in natural water samples.