Assay of ascorbic acid in human crevicular fluid from clinically healthy gingival sites by high-performance liquid chromatography.

The volume of fluid on filter paper strips was measured with a Periotron, eluted, and the ascorbic acid measured by chromatography. In preliminary experiments, pre-impregnation of the strips with citric acid increased the recovery of standard ascorbic acid from 37 to 89% and significantly reduced loss of water from the strips over a 3 min period. Samples of crevicular fluid were then collected from clinically healthy gingival sites of 21 healthy volunteers using pre-impregnated strips and assayed for ascorbic acid concentration, together with samples of blood plasma. The mean ascorbic acid concentration in gingival crevicular fluid (207.3 mumol/l; SD: +/- 81.8) was significantly higher (p less than 0.001) than the corresponding plasma concentration (mean 72 mumol/l; SD: +/- 23.3).