Determination of lactate in human saliva with an electrochemical enzyme probe

Electrochemical biosensors for lactate were assembled and used for the determination of lactic acid in saliva. Saliva was collected from healthy subjects and immediately screened for its lactate content. The electrochemical and biological interferences from saliva were discriminated by using a dual platinum electrode and blocking membranes. The stability, reproducibility and lifetime of the probe were studied. Lactate was measured in eight subjects in fasting conditions and after eating, showing an increase in lactate for each subject after meals. Correlation with a spectrophotometric lactate measurement is reported. Subjects before, during and after physical exercise showed consistent variations of lactate in saliva.