title: [Micro-determination of fluoride in biological samples by pyrohydrolysis and flow-injection analysis using a fluoride ion-selective electrode].
abstract: An apparatus has been developed for the isolation of fluoride in biological samples through pyrohydrolysis. With this apparatus, it is possible to determine both organic and inorganic fluorocompounds with a recovery close to 100% and precision within 5%. The high recovery rate can be expected even for highly heat-resistant compounds such as CaF2, without using WO3 as a catalyst. For determination of the isolated fluoride, a separate apparatus was developed in which flow-injection analysis was used in conjunction with a fluoride ion-selective electrode as a detector. With this apparatus, fluoride in a sample solution with a volume as small as 0.2 ml, and at a concentration as low as 0.5 microgram/l, can be determined within 3 minutes with a precision of several percent. Combined use of the two apparatuses makes it possible to determine fluoride in different biological samples within 10-15 minutes with a precision of several percent, free from external contamination. By selecting suitable conditions for analysis and using a 1 g sample, it is possible to determine fluoride at a concentration as low as 5 ng/g. By employing these apparatuses, the fluoride content in different biological samples has been determine and the effectiveness of their use confirmed.
authors.affiliation: School of Medicine, Iwate Medical University, Iwate.
authors.forename: K
authors.initials: K
authors.lastname: Itai
mesh_terms: D000328:Adult; D005260:Female; D005459:Fluorides / Q000032:analysis* / Q000097:blood; D006197:Hair / Q000737:chemistry; D006801:Humans; D008297:Male; D008722:Methods; D008875:Middle Aged; D009262:Nails / Q000737:chemistry
chemical_list: D005459:Fluorides