AU169: Determination of Silicate and Inorganic Anions in High Purity Water Using Sequential Detection and AutoPrep

Instrument Type: IC

Silicate is monitored in ultra high purity water because it is one of the first ions to break through deionization cartridges used for water purification. AN 170 showed how an ion chromatography system can determine sub-μg/L concentrations of silicate by visible absorbance after a post-column reaction. In these waters, low μg/L and sub-μg/L concentrations of inorganic anions and short chain organic acids are also determined. This Application Update (AU) shows how low concentrations of inorganic anions, organic acids, and silicate can be determined in one injection.

AN170: Determination of Silicate in High-Purity Water Using Ion Chromatography and Online Sample Preparation.

Instrument Type: IC

The water used in the manufacture of semiconductors and other electronic components must be extremely pure, referred to as ultra high-purity water (UHPW). The production of UHPW includes deionization to remove corrosive strong acid anions. Deionization cartridges exhaust their capacity over time. To ensure the early recognition of cartridge depletion, silicate must be detected at concentrations lower than 1 μg/L. These low detections limits can be achieved by pre concentrating UHPW on a Dionex IonPac AG4A-SC column, then separating the concentrated sample on a Dionex IonPac AS17 column set.