AWWA JAW56404

Being able to detect and quantify aqueous anions such as cyanide (CN-) and perchlorate (ClO4-) in drinking water and perfluorooctylsulfonate (PFOS) in wastewater is important to public health and the environment. Up until now, ion chromatography or mass spectrometry were the only ways to detect microgram-per-litre concentrations of these anions of concern. However, this study discovered that Fournier transform infrared (FTIR), a common and potentially portable spectroscopic technique, can be used to detect and identify certain aqueous anions of concern at small concentrations in favorable cases even when competing anions are present. In addition, the method reported did not require pretreatment of the aqueous samples for the detection and identification of the three substances. Using the modified crystal and after 60- min analyses, detection limits for CN-, ClO4-, and PFOS were 5, 3, and 25 ug/L, respectively. Previously, a commercial IR spectrometer could detect these anions only at concentrations that were 4,000-100,000 times higher. Moreover, an FTIR spectrometer is more robust and easier to maintain than an ion chromatograph or a mass spectrometer. Although this article does not describe a new method that is ready for field or plant use, it reports a scientific discovery that will be studied in other laboratories. The authors also predict that manufacturers will pursue this information to develop new instruments that will provide water suppliers with a more robust and potentially far less expensive device for determining concentrations of CN-, ClO4-, PFOS, and other substances at extremely low levels. Includes 44 references, table, figures.