Comparison of two cryptand separator columns for the determination of trace chloride in semiconductor-grade nitric acid.
Improved ion-chromatographic approaches for measuring trace chloride in nitric acid are presented. Two columns, the IonPac Cryptand A1 and a higher-capacity Cryptand prototype, were tested and compared. Also, the use of a Continuously Regenerated Anion Trap Column (CR-ATC) was evaluated for its ability to purify electrolytically generated eluent. Nitric acid (70%) was used as the test matrix and chloride was used as the test analyte; prior to injection, the nitric acid was diluted to 0.7% for the A1 column and to 2.8% for the prototype column. Chloride could be quantified in only 20 min on either column; detection limits computed for 70% HNO3 (at 95% confidence, alpha = beta = 2.5%) were 1.8 and 1.5 ppm for the A1 and prototype columns, respectively. Results also showed that the CR-ATC was necessary for obtaining acceptable acid blanks.
Vanatta
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LE
Air Liquide - Balazs Analytical Services, Box 650311, MS 301, Dallas, TX 75265, USA. lynn.vanatta@airliquide.com
Woodruff
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A
Coleman
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DE
D000837:Anion Exchange Resins / Q000737:chemistry*; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000737:chemistry; D002712:Chlorides / Q000032:analysis*; D002852:Chromatography, Ion Exchange / Q000295:instrumentation* / Q000379:methods; D017942:Nitric Acid / Q000032:analysis* / Q000737:chemistry; D015203:Reproducibility of Results; D012666:Semiconductors
D000837:Anion Exchange Resins; D019086:Bridged Bicyclo Compounds, Heterocyclic; D002712:Chlorides; C006071:cryptating agent 222; C053547:cryptating agent 221; D017942:Nitric Acid