Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.22.36 (caspase-1)
 6,285 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ion-exclusion chromatography (ICE) followed by ion chromatography (IC) was used for the determination of trace anionic contaminants in concentrated weak acids. The ICE separation was used as a pretreatment step to isolate the contaminant anions of strong acid from the excess of matrix ions. Then a fraction containing the analyte ions was separated using IC with suppressed conductivity detection. Microbore-ion-exchange columns were chosen to address the increased purity requirements for use of these concentrated acids in semiconductor applications. The chromatographic conditions were optimized for determining trace chloride, sulfate, phosphate, and nitrate in concentrated 24.5% (v/v) hydrofluoric acid; trace chloride, sulfate, and nitrate in concentrated 85% (w/w) phosphoric acid and trace chloride and sulfate in concentrated 0.7% (v/v) glycolic acid. Method detection limits for the anions of interest were below 100 micrograms/l.
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PMID:Determination of trace anions in concentrated weak acids by ion chromatography. 1045 78

Modifications have been made to the method of ion-exclusion pre-separation followed by ion exchange with conductivity detection for the determination of trace levels of chloride, sulfate and nitrate in concentrated phosphoric acid. Ion-exclusion separation and pre-concentration of impurity anions is performed using Dionex AS6-ICE and AS11-HC (4 mm) columns, respectively, with water eluent. Final separation is performed using Dionex AG11-HC and AS11-HC (2 mm) columns, KOH gradient elution, and suppressed conductivity detection. Improvements to the method include addition of an autosampler and eluent generator, and use of external standard calibration. These instrumental and procedural changes significantly improve the method's throughput, while the method's capability relative to phosphoric acid specifications is maintained, as verified through statistical evaluation of control sample analyses. Detection limits of 60, 680, and 4,0 ppb (w/w) are obtained vs. semiconductor-grade phosphoric acid specifications of 1000, 12,000, and 5000 ppb for chloride, sulfate, and nitrate, respectively.
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PMID:Automated trace anion determinations in concentrated electronic grade phosphoric acid by ion chromatography. 1210 42