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Critical parameters in the barium perchlorate/Thorin titration of sulfate.
Haartz-JC; Eller-PM; Hornung-RW
Anal Chem 1979 Nov; 51(13):2293-2295
The effects of pH and solvent concentration on recovery rates of atmospheric sulfur (7704349) containing species by the barium- perchlorate (Ba(ClO4)2) and Thorin method of titration were studied. Titrations of Ba(ClO4)2 standardized with 2-propanol (PrOH), adjusted for pH, and marked with Thorin indicator solution were performed with standard sulfate solutions, and recoveries were determined. At a pH of 3.5, low recoveries were achieved when less than 70 or more than 90 percent PrOH was added to the titrant. At a pH below 3.0 or a PrOH concentration of less than 80 percent, the volume of titrant required for detection increased and analytic precision decreased significantly. The authors conclude that optimal sulfate recovery with the Ba(ClO4)2 and Thorin titration method is obtained if the pH is in the 3.5 to 4.5 range and the PrOH concentration is between 82 and 87 percent.
NIOSH-Author; Acidity; Analytical-methods; Chemical-analysis; Sulfur-compounds; Analytical-processes; Laboratory-techniques; Analytical-chemistry
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