December 2009, Sunnyvale, CA—Dionex announces two recently approved methods for the determination of disinfection by products in drinking waters.

EPA Method 302.0: Determination of Bromate in Drinking Water Using Two-Dimensional Ion Chromatography with Suppressed
Conductivity Detection

EPA Method 557: Determination of Haloacetic Acids, Bromate, and Dalapon In Drinking Water by Ion Chromatography Electrospray Ionization Tandem Mass Spectrometry (IC-ESI-MS/MS)

Method 302 is a two-dimensional (2-D) IC method that was developed to provide a more robust solution for drinking waters with high concentrations of anions compared to the post column method 317 and 326. Using a Reagent-Free™ IC (RFIC™) system, EPA 302.0 allows the user to just add water to each system instead of preparing eluents and unstable or toxic post-column reagents. EPA 302 uses a 2-D system setup. 1) the first system partially resolves the matrix, andremoves and traps a time segment containing bromate, and 2) reruns this time segment on a second system. Both systems only require the addition of distilled water. This method can be performed using two IC systems, or a dual ICS-3000 system. Method 302 is suitable for all waters which are regulated for bromate compliance monitoring.

EPA 557 is an alternative to methods 552.1, -.2, and -.3, which use GC/ECD based detection. The 552 methods require extensive
sample preparation—laborious extraction, 2 hr. derivatization, and pH adjustment; pretreatment that can take up to 3-4 hours per
sample. Alternatively, 557 is a direct injection technique with no sample preparation that uses an RFIC system and hydroxide eluent for ion-exchange separation prior to MS/MS detection. The newly developed IonPac® AS24 column provides complete chromatographic resolution for each analyte, even in high-ionic-strength waters. This allows diversion of suppression-causing anions to waste prior to entering the ESI source for exceptional sensitivity and detection.

To download the EPA methods, visit http://www.epa.gov/safewater/methods/analyticalmethods_ogwdw.html

Dionex (NASDAQ:DNEX) is a global leader in the manufacturing and marketing of liquid chromatography and sample preparation
systems, consumables, and software for chemical analysis. The company’s systems are used worldwide in environmental analysis and by the life sciences, chemical, petrochemical, food and beverage, power generation, and electronics industries. Our expertise in applications and instrumentation helps analytical scientists to evaluate and develop pharmaceuticals, establish environmental
regulations, and produce better industrial products.

Reagent-Free and RFIC are trademarks and IonPac is a registered trademark of Dionex Corporation.