Low-level calibration study for a new ion chromatographic column to determine berate in deionized water

In the semiconductor industry, there is interest in determining berate at s ub-ppb levels in ultrapure water, since berate is an early breakthrough ion from ion-exchange resin beds. Although dissolved silica is the most common species currently used to monitor the breakdown of the deionization system s, it is thought that berate probably breaks through earlier than silicate. To be of use as an early-warning indicator, berate must be determined at p pt levels. This paper discusses benchtop results with several new column pr oducts designed to deliver low-ppt detection limits for boron as berate. Th e system uses a prototype berate-specific concentrator column that is coupl ed to an ion-exclusion separator and suppressed-conductivity detection. The acidic eluent, containing mannitol, quantitatively elutes the berate from the concentrator. The analytical separation is performed using a specially designed ion-exclusion column. Data presented are from two multilevel calib ration studies. Included is a discussion of detection-limit calculations an d recommended formats for reporting results. (C) 1999 Elsevier Science B.V. All rights reserved.