Determination of diallyldimethylammonium chloride in drinking water by reversed-phase ion-pair chromatography–electrospray ionization mass spectrometry

A method for the direct determination of diallyldimethylammonium chloride (DADMAC) in water samples, using ion-pair liquid chromatography–mass spectrometry system was developed. The chromatographic separation was performed using a C18 column. The type, the concentration of ion-pair reagent and the pH were optimized to give good chromatographic retention and sensitivity for DADMAC. Quantification was achieved in the positive electrospray ionization mode using selected ion monitoring. The cone voltage was also studied to establish the optimal experimental conditions. Finally, the reproducibility of the proposed method was shown by good run-to-run and day-to-day precision values. No sample preparation was required and the detection limit was 0.1 μg/L. The method was used to detect residual DADMAC at drinking water treatment plants in Tianjin, north China. The concentration of DADMAC observed in drinking water ranged from below quantitation limit to 22.0 μg/L.