Small-footprint non-suppressed capillary ion chromatography mass spectrometry method for the determination of...

A portable capillary liquid chromatography system (capLC) coupled with a small footprint single quadrupole electrospray mass spectrometer (ESI-MS) was applied to the non-suppressed ion chromatographic separation and determination of oxyhalides as inorganic disinfection by-products in various water samples. The capLC was equipped with a Dionex IonPac AS19 capillary column (0.4 mm x 250 mm) and the separation was performed using an ammonium carbonate gradient in a mobile phase consisting of 50 % acetonitrile. Bromate (BrO₃^-), chlorate (ClO₃^-), perchlorate (ClO₄^-) and iodate (IO₃^-) were separated in under 20 min, using just 200 µL of eluent for one run, and were variously quantified in drinking water and swimming pool water samples using standard addition. The method limit of detection (LOD) of bromate was below the regulatory limit of 10 µg/L in drinking water, however the concentrations of oxyhalides in local drinking water were below the method LODs for all analytes. A high concentration of chlorate (116.3 mg/L) was determined in local municipal swimming pool water, together with measurable levels of bromate (235.4 µg/L) and iodate (67.2 µg/L). Results demonstrate the applicability of small-footprint non-suppressed capillary ion chromatography-mass spectrometry (IC‑MS) for the sensitive determination of oxyhalide disinfection by-products in various water samples, and support its potential use for on‑site monitoring in water treatment plants and recreational water facilities.