A COMPARISON OF TWO METHODS FOR DETERMINING THE pH OF MAINSTREAM CIGARETTE SMOKE

Abstract Two methods used to determine the pH of mainstream cigarette smoke (MSCS) were compared to find the fastest and least complicated method. Both methods involved measuring the pH of only the water-soluble portion of the particulate fraction of MSCS. In method one, the pH of an aqueous extract of glass-fiber filter pads containing total particulate matter (TPM) was measured. In the second method, pH was measured directly from a glass fiber pad containing TPM that was moistened with 3 ml of degassed deionized water. Both methods were able to distinguish pH differences in the differently constructed reference cigarettes evaluated and were reproducible with relative standard deviations of less than 3%. Determination of smoke pH directly from a moistened glass fiber pad containing trapped TPM was found to be less complicated and quicker than determining pH of an aqueous extract due to the elimination of the extraction step.