Direct analysis of Na, K, Mg and Ca in human saliva and correlations with physiological conditions†
Saliva is a biological fluid composed of several organic and inorganic compounds. Its rich composition, due to a complex formation process, allows saliva to be an important biological fluid for collecting information from an organism. Organic compounds have been largely studied and the correlation of their levels with physiological conditions are well reported in the literature. In this context, the aim of the present study was to investigate the mineral composition of saliva (Mg, Ca, Na and K in 109 individuals) in order to discover correlations with physiological conditions, such as biological gender, blood glucose disorders, osteoporosis, heart palpitations, decreased muscular mass and unintentional weight loss. A sample preparation study was carried on and direct analysis was chosen due to its many advantages over acid digestion. The results showed that the levels of the analytes varied largely and presented no identified patterns. However, through boxplot analysis, some statistical differences and correlations with physiological conditions could be found. In addition, 30 saliva samples of renal patients were collected in order to investigate variations in the levels of the analytes before and after hemodialysis. The results showed that the variations tended to form a pattern, which indicated a possible correlation between the hemodialysis procedure and these specific ions in human saliva.