Abstract
Dual-wavelength spectrophotometry made it possible to determine the isomeric guaiacolsulfonates separately in pharmaceutical preparations. The recommended procedure is as follows :
I. Determination of potassium guaiacol-4-sulfonate and guaiacol-5-sulfonate : A sample containing about 1.0 mg of guaiacolsulfonates is dissolved in water and diluted to 50 ml with 0.1 N sodium hydroxide. The content of 4-sulfonate is obtained from the absorbances at 242 nm and 258 nm with the standard solution. The content of 5-sulfonate is also obtained from the absorbances at 237.5 nm and 300.9 nm with proper standard solution.
II. Determination of potassium guaiacol-4-sulfonate and 5-sulfonate in pharmaceutical preparations : A sample containing about 100 mg of guaiacolsulfonates is dissolved into 100 ml of water and filtered with glass-filter (No.3). The initial 20 ml filtrate is discarded, and the subsequent 20 ml filtrate is passed through the freshly conditioned strongly-basic ion-exchange resin column. After washing with 0.1 N HCl-ethanol (flow rate 1 ml/min), elution is carried out with the same eluant with flow rate 4 ml/min. The eluate is collected and diluted to 200 ml in measuring flask. The determination of 4- and 5- sulfonates can be carried out by dual-wavelength spectrophotometry following the Determination I.
