A quantitative method for fluoride determination using RP HPLC and UV detection was developed. The method is based on the reaction of fluoride with triphenylhydroxysilane in highly acidic conditions and extraction of the reaction product into n-heptane. Chromatographic conditions as well as the derivatization parameters were optimized. LOQ for fluoride ion was evaluated as 0.25 μM (4.75 ppb) and linear range of response up to 75 μM (1.42 ppm) was obtained. The method was developed as a part of a procedure designed for the determination of total organic fluorine in natural waters, using SPE on a carbon sorbent and sodium biphenyl reagent for the defluorination reaction. LOD for a model compound, perfluorooctanoic acid, calculated for the complete procedure with 2000-fold preconcentration, is 20 ppt (n=4). Initial results show feasibility of total organic fluorine determination for environmental purposes.

Perfluoroalkyl substances (PFASs) are proliferated into the environment on a global scale and present in the organisms of animals and humans even in remote locations. Persistent organic pollutants of that kind therefore have stimulated substantial improvement in analytical methods. The aim of this review is to present recent achievements in PFASs determination in various matrices with different methods and its comparison to measurements of Total Organic Fluorine (TOF). Analytical methods used for PFASs determinations are dominated by chromatography, mostly in combination with mass spectrometric detection. However, HPLC may be also hyphenated with conductivity or fluorimetric detection, and gas chromatography may be combined with flame ionization or electron capture detection. The presence of a large number of PFASs species in environmental and biological samples necessitates parallel attempts to develop a total PFASs index that reflects the total content of PFASs in various matrices. Increasing attention is currently paid to the determination of branched isomers of PFASs, and their determination in food.FigureThe aim of this review is to present recent achievements in perfluoroalkyl substances (PFASs) determination in various matrices with different methods and its comparison to measurements of Total Organic Fluorine (TOF). Increasing attention is currently paid to the determination of branched isomers of PFASs, and their determination in food.

Roles of steroid hormones, and compounds that can influence their levels in cells, are of increasing interest in e.g. cancer research, partly because resistance to hormone therapies often complicates treatment. To elucidate the processes involved, the hormones and related compounds need to be accurately measured. Reversed-phase liquid chromatography with dynamic multiple reaction monitoring mass spectrometric detection in electrospray mode is capable of providing such measurements. Therefore, LC-MS/MS was developed for sensitive, selective analysis of 11 steroid hormones, cholesterol and two prostaglandins. The effects of the tissue matrix, and solid-phase extraction (SPE) sample clean-up, on the LC-MS/MS signals of the hormones were also investigated. The results show that the developed LC-MS/MS method, following SPE clean-up to reduce matrix interference, can detect selected steroids in extracts of mouse tissues. The method provides linear measurements of the steroids at concentrations up to few ng/μL, and limits of detection in the range 0.03-0.2 pg/μL (for some compounds lower than those of previously reported methods).

Since the perfluorinated organic compounds have been recognized as persistent organic pollutants present in the environment, food and living organisms, new analytical methods are being developed for their determination. Many of the described earlier methods focus on determination of particular fluorinated compounds, however, the specific compounds are only a part of all organic fluorine compounds present in environmental or biological samples.