Ion chromatography (IC) is a well-accepted technique for the monitoring inorganic anions in environmental waters, including surface, ground, drinking, and wastewaters and IC methods are specified by regulatory agencies for determining anions in these water samples. Typically these methods use standard (4 mm diameter) or microbore (2 mm diameter) anion-exchange columns. Scaling down from standard bore to capillary format (0.4 mm i.d.) brings many benefits to the analyst, including low eluent consumption and low waste generation. With such low mobile phase consumption, the system can remain running and be ready for analysis. Unfortunately the smallest available injection valve internal injection loop (400 nL) required that many water samples, including wastewater, be diluted as to not overload the IC column. This dilution is not needed for standard bore IC and thus added an extra step to the analysis. This presentation shows how a new injection valve with a 100 nL internal injection loop can be used for wastewater and municipal drinking water and anion analyses without sample dilution. We show the method calibration, determine the detection limits, and measured the method’s precision and accuracy. The calibration was linear over a wide range for the standard anions (e.g. 0.2 to 300 mg/L for chloride) and we found that the method was both accurate (86–106% spike recoveries) and precise (RSD &lt; 3.2%) for common anions such as fluoride, chloride, nitrite, sulfate, nitrate, and phosphate. Overall we demonstrate that environmental water samples can be successfully analyzed without dilution using a system that is always on while consuming little eluent and generating little waste.<br/>

Determination of inorganic anions in wastewater using capillary ion chromatography

255th National Meeting (2018)

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