Rapid and simultaneous determination of dichloroacetic acid, trichloroacetic acid, ClO3−, ClO4−, and BrO3− using short-column ion chromatography-tandem electrospray mass spectrometry

A simple, accurate and reliable analytical method has been developed for the simultaneous determination of dichloroacetic acid, trichloroacetic acid, chlorate, perchlorate and bromate by using ion chromatography coupled with electrospray ionization tandem mass spectrometry (IC-ESI-MS/MS). To reduce the sample analysis time, a short column AG18 was evaluated to perform fast separations of the target analytes. Using the combi-nation of 0.1 M aqueous methylamine solution and acetonitrile as the mobile phase under the optimized gradient elution mode, all 5 analytes could be resolved satisfactorily from the column within 5 min. The limits of detection and limits of quantification for 5 analytes were in the range of 0.09-0.28 mu g/L and 0.28-0.84 mu g/L, respectively. The method recoveries for the analytes spiked into tap water at a concentration of 5 mu g/L were in the range of 69.6-118.3%; the precision values (as intra-and inter-day relative standard deviations) were in the range of 5.1-9.9%. The proposed method was subject to very limited interference from the common substances in the water matrix, such as Cl- (25-200 mg/L), SO4- (25-200 mg/L), HCO3 -/CO3 2-(1-6 mM) and natural organic matter (1-8 mg/L). For environmental applications, the method successfully monitored haloacetic acids and oxyhalides yields in laboratory chlorination experiments.