DETERMINATION OF FLUORIDE IN BIOLOGICAL SAMPLES BY A NONFUSION DISTILLATION AND ION-SELECTIVE MEMBRANE ELECTRODE METHOD

A nonfusion distillation technique has been developed to prepare biological samples for a rapid determination of fluoride content using a solid-state membrane electrode. The addition of a recommended ionic strength and pH buffer to the distillate allows a direct determination of the fluoride concentration. The overall error was less than 0.5% and the method is sensitive to the 2-ppm level in biological samples. The method is simpler than the longer and more difficult AOAC method, but gives results which compare in precision. © 1969, American Chemical Society. All rights reserved.