Sulfur Dioxide Determination

Sulfur dioxide in the sample causes a negative interference of approximately 1 mole of ozone per mole of sulfur dioxide, because it reduces the iodine formed by ozone back to potassium iodide. When sulfur dioxide concentrations do not exceed those of the oxidants, a method commonly used to correct for its interference is to add the amount of sulfur dioxide determined by an independent method to the total detector response. A second method is to remove the sulfur dioxide from the sample stream with solid or liquid chromium trioxide scrubbers. Because the data on the performance or these sulfur dioxide scrubbers are inadequate, the performance for each oxidant system must be established experimentally. 

For total sulfur dioxide determination, distillation procedures are preferred (3, 4, 6, 22). Careful attention to details is necessary since the methods are empirical (16, 36, 37). Automated analysis (38) also can be used (up to 20 samples per hr). For a summary of investigations on sulfur dioxide determination see Wucherpfennig (39). 

Sulfur Dioxide Determine as directed under Sulfur Dioxide Determination, Appendix X, using 0.5 g of sample, accurately weighed. 

Sulfur Dioxide Determine as directed under Sulfur Dioxide Determination, Appendix X. 

Sulfur Dioxide Determine as directed under Sulfur Dioxide Determination, Appendix X. However, instead of using a 50-g sample, dissolve a 20.0-g sample in 100 mL of a 5% alcohol in water mixture, and proceed as directed under Sample Introduction and Distillation. 

Sulfur Dioxide Determine as directed in the general method, Appendix X, using the following method under Sample Introduction and Distillation Transfer about 20 g of the sample, accurately weighed, into flask C, and add 20 mL of ethanol to moisten the sample. Add 400 mL of water, swirling vigorously to... 

Cals, R. E. and Stuk, G. J., Copolymerization of Acrylamide with Sulfur Dioxide. Determination of the Effect of Copol3nnerization Temperature on the Monomer Sequence Distribution by 13C N.M.R., Polym., 19 179 (1978). 

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