Analyses of organic acids and inorganic anions and their relationship in human saliva before and after glucose intake

Abstract

The goals of this study were to determine the content of organic acids and inorganic anions in human saliva by using an ion chromatography method, to compare the organic acid and inorganic anion concentrations before and after a sugar rinse, and to investigate the relationships between the levels of each compound. Saliva samples were obtained from 37 subjects before and up to 60min after intake of a 10% glucose solution. Concentrations of seven organic acids (lactate, acetate, propionate, formate, butyrate, pyruvate, and valerate) and four inorganic anions (fluoride, chloride, sulphate, and phosphate) were determined via anion-exchange chromatography with an anion-suppressed conductivity detector. The current analytical method showed good precision and accuracy. Organic acid levels increased after the sugar rinse and recovered to control levels within 20min. Acetate was the predominant organic acid detected in the saliva before the sugar rinse, and lactate was the predominant organic acid detected after the sugar rinse. The overall organic acid content generated by the sugar rinse was positively correlated with the chloride, sulphate, and phosphate concentration, but somewhat negatively correlated with the fluoride concentration. Organic acid levels are increased in human saliva by glucose metabolism. Furthermore, the formation of organic acids following glucose intake is influenced by the prevailing anion content.