Stability of various sodium hypochlorite solutions.

Although the manufacturers use at least a 2-yr expiration date for sealed undiluted NaOCl solutions, chemical stability of NaOCl may be adversely affected by many factors. The purpose of this study was to investigate the effects of storage temperature, concentration, and time on the stability on three different brands of commercial household bleaching agents as a source of NaOCl, and to compare the stability of these brands. All solutions showed degradation versus time; however, this degradation occurred very slowly except for the group of solutions containing 5% available chlorine stored at 24 degrees C. Solutions containing 0.5% available chlorine stored at 4 degrees C and 24 degrees C and 5% solutions stored at 4 degrees C showed satisfactory stability at 200 days. No significant difference was found among three brands in respect to their chemical stability.