A simple, rapid, and sensitive method is developed for the determination of UV filters in river waters by applying the vortex-assisted dispersive liquid-liquid microextraction based on solidified floating organic droplet technique followed by the injector port silylation (IPS) in a gas chromatography-tandem mass spectrometry system. Statistical experimental design methods including general factorial design, one factor at a time, and central composite face-centered design are used for optimization purposes. Under optimized conditions, 460 µL of acetone and 30 µL of 2-dodecanone are rapidly injected into a 10 mL water sample with 10% (w/v) NaCl at pH 2.5 and vortexed for 3 min. After centrifugation, 2 µL of the separated organic solvent is subjected to auto-IPS with 1 µL of bis (trimethylsilyl) trifluoroacetamide containing 1% trimethylchlorosilane, at 260 °C for 4.5 min in programmable temperature vaporization mode. As a result of the validation studies, the intra-day and inter-day precision indicated as relative standard deviation are less than 12.4% and 18.8%, respectively. For all UV filters, detection limits are between 1.1 and 5.5 ng L −1 and limit of quantitation values are between 3.1 and 16.6 ng L −1 . Successful recovery of extraction values (77.1%-107.4%) and good enrichment factors (231-350) are obtained.

Plant sterols are important agricultural products for human health and consequently, for nutrition industries. In the present study, free sterol contents of crude Turkish cottonseed oil samples have been determined in a single analytical run by using a solid phase extraction step prior to the detection with a gas chromatography coupled with a flame ionization detector. Free hydroxyl groups of Stigmasterol, β-Sitosterol, Campesterol and Brassicasterol were derivatized by using N-methyl-N-trimethylsilyl trifluoroacetamide to enhance their volatility and, sterol content of the samples were, then, separated from their matrix by using a octadecylsilane cartridge. The eluates were injected into the gas chromatographic system and satisfactory recovery ratios were obtained. After having validated the method, it was applied into the analysis for cottonseed oil samples for their free sterol levels.

UV filters (UVFs) are widely used in personal care and in industrial products for protection against photodegradation. In recent years, their potential toxicological and environmental effects have received growing attention. Due to their excessive use, their residue levels in the environment are gradually increasing and they tend to accumulate on biological wastewater treatment sludge. The utilization of sludge as fertilizer could be one of the main routes of UVF contamination in the environment. Therefore, the development of a reliable and sensitive method of analyzing their trace level residues in waste sludge samples is of great importance. The success of the method largely depends on the sample preparation technique in such complex matrices. This study presents a rapid, sensitive and green analysis method for eight UVFs in sludge samples, selected for their rather low no-observed-effect concentrations (NOEC). For this purpose, the QuEChERS methodology was coupled with in-port derivatization for subsequent detection of the targeted UVFs via GC–MS/MS. The analysis time was substantially shortened using this method, and reagent utilization was also reduced. The method was validated in the sludge samples, and high recovery (66–123%) and low RSD values (<25.6%) were obtained. In addition, major contributing uncertainty sources and expanded uncertainties were determined.