[Influence of the container and environmental factors in the stability of sodium hypochlorite]

This study was performed to analyze the chemical stability of sodium hypochlorite (with 2.6% or 26.0 mg/mL of free residual chlorine) in the various types of containers when exposed to different light levels. Over a period of eight months, several samples of that solution were put into containers made of glass (amber or clear) and plastic (opaque white, opaque green, or clear) with and without a top, and were exposed to three different lighting conditions (continuous light, total dark, and ambient light of the laboratory where the study was carried out). The stability of the solution was analyzed by measuring the concentration of free residual chlorine in the samples exposed as described above. The environmental factors tested were chosen as representative of the various conditions under which this effective, cheap, and widely available household disinfectant is often stored and used by the general public. The results indicated that chemical instability increased with the presence of light, the absence of a top, and the length of time the solution was stored. The most suitable containers were those made of amber glass, opaque green plastic, or opaque white plastic, although the last one offered the least protection of the three.