DETERMINATION OF SMALL SAMPLE VOLUMES IN THE ANALYSIS OF DRUGS AT SPECIFIC SITES IN THE ORAL CAVITY

Two methods for the determination of sample volumes between 0.2 and 0.6 mu l were compared by preparing standard curves for volumes over this range. The first method used a Periotron and the second the sample mass. A linear model was fitted and 95% confidence limits for volumes estimated by each method were calculated. This showed that use of either the maximum Periotron reading or the sample mass allowed estimation of volumes to within +/-0.056 mu l and +/-0.047 mu l respectively. It is proposed that measurement of sample mass provides a simple and accurate method to determine sample volume when analysing drug concentrations at specific sites in the oral cavity.