Organic anion composition of human whole saliva as determined by ion chromatography

Background: The majority of studies examining anionic composition in human saliva have focused on inorganic anions only, and accompanying organic anion concentration has often been overlooked in the development of artificial salivas. The purpose of this study was to examine the major organic anionic species profile of human saliva, with a view to gaining further insight into human salivary chemistry. Methods: Unstimulated whole saliva was collected from 11 healthy volunteers over a period of 18 months. Samples were subjected to ion chromatography for detection and quantification of organic and inorganic anions. Results: Among organic anions, acetate was predominant (0.24 +/- 0.38 mmol/l), with lactate (0.01 +/- 0.04 mmol/l), propionate (0.03 +/- 0.07 mmol/l), and formate (0.02 +/- 0.03 mmol/l) detected at lower levels. Acetate, propionate, and formate were detected in at least 80% of the saliva samples. Positive partial correlations were found between phosphate and sulfate (r = 0.510, p-value = 1.545 x 10(-4)), and between propionate and acetate (r = 0.836, p-value = 7.510 x 10(-14)). Conclusion: Organic anionic species were consistently detected at low levels in saliva samples collected longitudinally over a period of 18 months. These salivary components must be considered in order to understand saliva chemistry, and should not be neglected during the continuing development of artificial salivas. (C) 2014 Elsevier B.V. All rights reserved.