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. 1963 Jul;11(4):357–361. doi: 10.1128/am.11.4.357-361.1963

Adverse Effect of Ammonium Salts on the Antibacterial Activity of Paraformaldehyde Solutions

G E Myers 1, R G L McCready 1
PMCID: PMC1058002  PMID: 13936950

Abstract

The antibacterial activity of aqueous solutions of paraformaldehyde in concentrations from 0.1 to 0.4% (w/v) is bacteriostatic rather than bactericidal in the presence or absence of ammonium chloride. The presence of ammonium chloride significantly lengthened the time of exposure to paraformaldehyde necessary for inhibition of growth of the test organism (Staphylococcus aureus FDA 209) when unbuffered solutions were used. Elevation of the pH of the reacting mixture of paraformaldehyde and ammonium chloride by partial buffering lengthened the time of exposure necessary for inhibition of growth of the test organism. Decrease of antibacterial activity was concomitant with the disappearance of paraformaldehyde from the reacting mixture. The reaction of paraformaldehyde with ammonium chloride was rapid at room temperature (25 C) and at pH levels near neutrality. The fate of the reacting paraformaldehyde, including the possibility of the formation of hexamethylenetetramine or methylenimine, is discussed with particular reference to loss of antibacterial activity.

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Selected References

These references are in PubMed. This may not be the complete list of references from this article.

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