Development of a fluoride assay methodology for plasma from capillary blood samples

To optimise the quality of dental research involving fluoride assay and minimise between-laboratories fluoride analysis inconsistencies, standardised fluoride analysis techniques should be developed and tested. The aim of this collaborative project was to compare potential methods for fluoride analysis in microlitre-volume plasma samples containing nano-gram amounts of fluoride. The study sites comprised four internationally recognised laboratories with track record expertise in fluoride analysis: Teesside University (UK), University of São Paulo (Brazil), Newcastle University (UK), and Indiana University (US). All collaborative partners analysed a set of standardised biological samples as well as plasma using the established HMDS-diffusion method, a micro-diffusion method and known-addition technique. The results showed that the known-addition technique could be a suitable alternative for measurement of fluoride in plasma with microlitre-volume samples