A new and improved gas Chromatographic method for the determination of fluoride in plasma and faeces

Abstract

A method is described that extracts fluoride selectively as trimethylfluorosilane using carbon tetrachloride and trimethylchlorosilane . Drawbacks of other methods as well as advantages of the proposed method are discussed. The method is directly applicable to plasma and faeces samples, has a short gas chromatographic run time due to the use of a backflush technique and is suitable for automation. Its lowest quantifiable limit for plasma and faeces is 10 micrograms/l and 1 microgram/g fluoride respectively, using 1.0 ml or 1.0 g samples. Preliminary pharmacokinetic parameters of fluoride obtained in two subjects are reported.

Application of Gas Chromatography to Determination of Total Organic Fluorine after Defluorination of Perfluorooctanoic Acid as a Model Compound

“…6,7 The reagent used for derivatizationTPSiOH has a higher boiling point than the previously used reagents [11][12][13] so it is easier to prepare the samples as well as conduct separation by GC with a suitable temperature program. The presence of three phenyl groups makes TPSiOH more universal as a derivatization reagent because the reaction product may be determined by the GC and the HPLC.…”

“…GC determination of fluoride with flameionization detection (FID) were developed in 1960s with derivatization of fluoride ion to volatile triethylfluorosilane 11 or trimethylfluorosilane. 12,13 The total content of fluorine in whole blood, serum/plasma and other biological samples was determined by GC using oxygen bomb combustion and reaction with triethylsilanol. 14 In the GC determination of fluorinated organic compounds after suitable derivatization the electron capture detection (ECD) can be used, 15,16 but as it was recently showed in the determination of perfluorinated carboxylic acids (PFCA) C6 to C12 after the derivatization with isobutyl chloroformate, evidently better values of the LOD can be obtained for the mass spectrometry (MS) detection with electron impact ionization, than the ECD.…”

Determination of fluoride as fluorosilane derivative using reversed‐phase HPLC with UV detection for determination of total organic fluorine

“…Comparing the developed procedure with other chromatographic methods, GC‐FID procedures exhibit derivatization and measurement times either shorter or at a comparable time scale and comparable LODs 29, 48. Conventional IC may suffer from frequently emphasized overlapping of fluoride and void volume peaks.…”

“…Other separation techniques are less frequently chosen for fluoride determination. Reported GC methods are based on a selective derivatization reaction with silanol, allowing fluoride quantitation at the level of 5–10 ppb 28, 29. Determinations using CE with CDs and indirect UV detections have been demonstrated with LODs of approximately 20 ppb 30 and 100 ppb 31, respectively.…”

“…Considering common use of HPLC‐UV instrumentation in analytical laboratories, we undertook a task of developing a RP‐HPLC method for fluoride determination. The foundation of the method is a reaction originally employed for the determination of fluoride by GC 28, 29, 37, based on the derivatization of fluoride with hydroxysilane to form a corresponding fluorosilane (Eq. 1).…”