Determination of polyvinylpyrrolidone by an lodine titration method

Abstract

A new method, partly based on a procedure originally suggested by Cannan (2), for the analytical determination of PVP in serum and urine samples has been developed. Creatinine in urine does not interfere. Materials, such as proteins in serum, which do interfere, are first precipitated out by addition of ethyl alcohol. An iodine solution is then added to the clear alcoholic solution; the iodine precipitates out a PVP-I 2 complex which is separated by centrifugation, washed, dissolved in a suitable solvent such as methyl Cellosolve, and titrated with standard thiosulfate. The advantage of this method is that, by proper calibration, good results (usually within ±6% and almost always within 10%) over a very wide range of PVP concentrations (1 to 150 mg PVP/ml) can be obtained on the original sample without rerunning the analysis at other sample dilutions. A more detailed account of the development work on the iodine titration method is to be found in a report to the Office of Naval Research (5).