DETERIORATION OF SODIUM HYPOCHLORITE SOLUTIONS (“Chlorinated Soda” Solutions)

The following note on two hypochlorite solutions is published as a slight addition to the inconclusive available information concerning the rate of deterioration of solutions containing sodium hypochlorite:

Hyclorite.—This is a solution of chlorinated soda, 100 gm. of which is said to contain sodium hypochlorite 4.05 gm., sodium chlorid 3.20 gm., calcium hydroxid 0.25 gm., inert ingredients 0.92 gm. It is declared to contain, when placed on the market, not less than 3.85 per cent. of available chlorin, and to deteriorate at the rate of about 12 per cent. per year. In order that the available chlorin content at the time of use may be judged, the date of bottling is stamped on each package. The solution is prepared by decomposing chlorinated lime suspended in water with sodium carbonate and adding to the solution obtained a freshly prepared solution of electrolyzed sodium chlorid. The composition and keeping qualities of hyclorite were reported on by this laboratory (Ann. Rep. Chem. Lab., A. M. A. 9:123, 1916). Hyclorite is fully described in New and Non­official Remedies, 1918, p. 153.

To further check the keeping qualities of hyclorite, a specimen received from the manufacturer in June, 1918, and said to have been bottled in April, 1918, was examined in September, 1918. It was found to contain 3.6 per cent, “available chlorin” (equivalent to 3.79 gm. sodium hypochlorite in 100 gm.). This indicated a loss of 6.2 per cent. during five months (equivalent to 14.9 per cent. per year) on the assumption that it contained the amount of “available chlorin” declared on the label.

Concentrated Solution Sodium Hypochlorite-Mulford.—This is described as a 5 per cent, aqueous solution of sodium hypochlorite containing free chlorin equivalent to from 0.2 to 1 per cent. sodium hypochlorite. It is prepared by treating a solution of sodium carbonate and sodium bicarbonate with chlorinated lime. The solution is filtered and standardized by determining the “available chlorin” and adjusting it to contain the equivalent of 5 per cent. of sodium hypochlorite.

It is proposed for use in the irrigation treatment of infected wounds after dilution with nine times its volume of water and the addition of a determined amount (stated on the label of each bottle) of boric acid to render it neutral to phenol­phthalein. The manufacturer has found that development of a red color (due to formation of permanganate from the manganese contained in the chlorinated lime) is indicative of deterioration, and therefore warns against any solution which has become pink.

A specimen of concentrated solution of sodium hypochlorite-Mulford was sent the Council on Pharmacy and Chemistry in June, 1917, with a view of having the product admitted to New and Non­official Remedies. At that time it was found to contain 4.18 per cent. “available chlorin” (equivalent to 4.4 gm. sodium hypochlorite in 100 gm.). Another specimen received at the same time and kept unopened in a dark place, was examined in September, 1918, and was found to contain 2.88 per cent. available chlorin (equivalent to 3 gm. sodium hypochlorite per 100 gm.). On the assumption that the second specimen contained, at the time of its receipt, the amount of “available chlorin” found in the first, this second specimen lost 31 per cent. of its “available chlorin” during fifteen months.

At the time the specimens were received from the Mulford Company, the firm reported experiments which were under way to determine the keeping qualities of the solution. These experiments indicated marked deterioration of the specimens, which had become red from permanganate formation, and also that one specimen, which had not become red, had lost 5 per cent. of its available chlorin in one month. The Mulford Company explained that when sufficient data had been accumulated, a decision would be made either as to placing a time limit on the solution or making a claim as to the rate of deterioration. When the extreme deterioration found by this laboratory was reported to the Mulford Company, the firm replied that this was a much greater loss than the average deterioration found in its chemical laboratory, namely, an average of 10 or 12 per cent. per year. It advised that because of the instability of concentrated solution of sodium hypochlorite, its manufacture had been discontinued.—(From Reports A. M. A. Chemical Laboratory, 1918, p. 81.)