在没有溴离子（Br-）的情况下，标准方法中的方法5710B足以测量三卤甲烷（THM）前体浓度，前提是在培养结束时保持3 mg/L的游离有效氯（FAC）残留，并且标准方法中的方法5710E适用于预测消费者水龙头处的THM浓度。在Br-存在的情况下，方法5710B足以测量THM前体浓度，前提是只需要总前体。由于初始Br-/平均FAC剂量摩尔比影响溴取代，因此无法使用方法5710B预测THM物种浓度。 相反，必须使用方法5710E。在评估THM前体去除装置工艺时，这一点尤其重要，因为使用方法5710B可能表明装置工艺废水中的溴替代量大于进水中的溴替代量。包括12个参考文献、表格和图表。

In the absence of bromide ion (Br-), method 5710B from Standard Methods is adequate for measuring trihalomethane (THM) precursor concentrations, provided a free available chlorine (FAC) residual of 3 mg/L is maintained at the end of incubation, and method 5710E from Standard Methods is appropriate for predicting THM concentrations at the consumer's tap. In the presence of Br-, method 5710B is adequate for measuring THM precursor concentrations provided only total precursor is desired. Because the initial Br-/average FAC dosage molar ratio influences bromine substitution, THM species concentrations cannot be predicted using method 5710B. Instead, method 5710E must be used. This is particularly important when evaluating THM precursor removal unit processes when the use of method 5710B may indicate greater bromine substitution in the unit process effluent than in the influent. Includes 12 references, tables, figures.