Separation and identification of synthetic antigens of hexoestrol residue in animal derived food by HPLC-MS

Ruthenium oxide nanoparticles immobilized over Citrus limetta waste derived carbon material for electrochemical detection of hexestrol

Hexestrol is a non-steroidal estrogen which causes carcinogenic effects in animals. It is therefore important to develop sensitive and selective test methods for its early detection. Herein, we report the development of an electrochemical sensor to detect hexestrol in ultralow concentrations. In order to devise a simple and cost-effective hexestrol sensing electrode, attention is paid to the development of biomass-derived porous carbon (PCB) with large surface area and suitable porosity to immobilize ruthenium oxide nanoparticles (RuO₂ NPs, 3-4 nm). The leftover Citrus limetta pulp is chosen as waste biomass since it has N and O based chemical species. Structural, morphological and compositional analysis of PCB and RuO₂@PCB revealed well-dispersed RuO₂ NPs over the PCB surface. High loading (5.27 at%) of Ru content is achieved due to the large surface area of PCB. Cyclic voltammetry, chronoamperometry and differential pulse voltammetry results suggest that the RuO₂@PCB/ITO electrode is capable of detecting hexestrol concentration (in the range of 1 × 10^-7-2 × 10^-5 M). The practical application of hexestrol detection in milk samples demonstrates the recovery from 96.28 to 101%.

Development and validation of a confirmatory method for the determination of stilbene estrogens in ostrich serum

A simple and accurate ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for the first time as a confirmatory method for the simultaneous determination of stilbenes - hexestrol and diethylstibestrol in serum. Extraction was based on a simple acid denaturation of protein followed by liquid-liquid extraction using methyl tert butyl ether. Extracts were directly injected into the UHPLC-MS/MS without further purification. Excellent recoveries in the range 82-99% and 91-128% were obtained for hexestrol and diethylstibestrol, respectively. Both within-day repeatability and between-day reproducibility were generally satisfactory with RSD <20%. The linearity of the internal standard based matrix-matched calibration curve measured as the coefficient of regression (r²) was generally >0.99 for both hexestrol and diethylstibestrol. Both matrix effect and uncertainties associated with sample preparation and instrumental analysis were significantly reduced with the use of a deuterated compound (hexestrol-d4) as internal standard. The LOD and LOQ were 0.09 and 0.08 ng/ml, and 0.28 and 0.25 ng/ml, respectively, for hexestrol and diethylstibestrol. The method was found to be suitable for the simultaneous determination of hexestrol and diethylstibestrol in serum.

Electrochemical fabrication of polymerized imidazole-based ionic liquid bearing pyrrole moiety for sensitive determination of hexestrol in chicken meat

1-[3-(tert-Butoxycarbonylamino)propyl]-3-[3-(N-pyrrole)propyl]imidazolium tetrafluoroborate [(t-Boc-APPPI)BF4], which is a novel pyrrolyl-functionalized ionic liquid, was synthesized and characterized. Subsequently, it was electrochemically deposited onto a glassy carbon electrode surface to fabricate a polymerized ionic liquid film electrode. X-ray photoelectron spectroscopy, scanning electron microscope and electrochemical impedance spectroscopy were used to confirm the successful polymerization of ionic liquid. Voltammetric behaviors of hexestrol at the film electrode were investigated. The oxidation peak slightly shifted towards positive potential, however, dramatically increased in peak current. Experimental conditions for hexestrol determination were optimized. The oxidation peak current is linear with hexestrol concentration in the range of 1.0 × 10(-8)-1.0 × 10(-5) mol L(-1). The detection limit is estimated to be 2.1 × 10(-9) mol L(-1) (S/N=3). Hexestrol in chicken meat was determined using the film electrode with good accuracy.