Objective To screen disruptors in the determination of anionic surfactant in drinking water tested by flowing injection analysis, and to study the best material and condition for masking disruptors.

Methods In the experiment of screening disruptors, reference materials according to 25 common chemical substances in water were used to prepare water samples, and the concentration of each material was based on the maximum limits for drinking water in "Standards for Drinking Water Quality"(GB 5749-2006). The optimal masking agents and the best experimental condition were based on the screening results.

Results Calcium and magnesium were the most important disruptors in the determination of anions surfactant in drinking water by flow injection analysis. The disruption of calcium and magnesium in water could be masked by adding EDTA-2Na and adjusting to pH=10. The recovery rate of this method was not statistically different from the national standard method(P>0.05).

Conclusions The interference of calcium and magnesium in the determination of anionic surfactants in drinking water by flow injection analysis could be masked by adding suitable amount of EDTA-2Na. The merit of this method was high in efficiency, sensitivity and precision, and the accuracy of this method can meet the requirements of national examination standard.