Qualitative gas-liquid chromatography of some non-volatile acids produced by human whole saliva

Abstract

Whole saliva was incubated for 1, 3 and 5 hr with glucose, wholemeal flour, white flour, wheat offals and wheat bran. Acids produced were isolated in a strongly basic anion-exchange resin, displaced from the resin with 12 M formic acid, and the non-volatile acids recovered in ether-methanol (9 : 1 v v ) after evaporation of the formic acid at 40 °C. Methyl esters, prepared by reaction with diazomethane, were separated on a butanediol succinate column in a Perkin Elmer F 11 gas Chromatograph. Lactate, succinate, fumarate, malate and (less conclusively) α-ketoglutarate were identified in most samples, but certain differences between substrates were shown. It is suggested that the accumulation of Krebs cycle acids may be explained by some oral bacteria utilizing aerobic pathways such as the glyoxylate cycle in addition to the Krebs cycle. The possible significance of these acids in dental caries is discussed.