Determination of ractopamine residue in animal derived foods using electromembrane extraction followed by liquid chromatography tandem mass spectrometry.

A simple, sensitive and accurate analysis method based on electromembrane extraction (EME) and liquid chromatography tandem mass spectrometry (LC-MS/MS) was developed for the extraction and determination of ractopamine residue in animal derived foods for the first time. Several parameters that affecting the extraction efficiency of EME were optimized, including the type of supported liquid membrane (SLM), chemical composition of acceptor solution, extraction voltage and extraction time. Under the optimum conditions, the developed EME-LC-MS/MS method obtained a wide linear range (1-1000 ng/g), low limit of detection (0.07-0.11 ng/g), satisfactory recoveries of 80.3-108.8%, and high precision (5.5-7.9%). The developed method showed advantages of green, fast mass transfer rate, excellent clean-up ability, high accuracy and high sensitivity, which demonstrated its great potential for monitoring the illegal use of hazardous substances in foods.

Selective extraction and determination of steroidal glycoalkaloids in potato tissues by electromembrane extraction combined with LC-MS/MS.

For the first time, electromembrane extraction (EME) combined LC-MS/MS was applied to extract and determine α-solanine and α-chaconine in different potato tissues using NPOE containing 20% (v/v) DEHP as supported liquid membrane (SLM). Under the optimal conditions, the proposed EME-LC-MS/MS method was evaluated using spiked fresh potato peel sample. The linear range for α-solanine and α-chaconine was 5-1000 ng mL-1 (R2 > 0.9991), with LOD and LOQ of 1.2-1.5 ng mL-1 and 4.1-5.2 ng mL-1, respectively. Repeatability for α-solanine and α-chaconine at three concentration levels was satisfactory (<4.9%), and recoveries ranged from 73% to 106%. Finally, the EME-LC-MS/MS method has been successfully employed to determine α-solanine and α-chaconine in sprouted potato peel and tuber samples, indicating that EME exhibited high selectivity and efficient sample clean-up capability. Consequently, EME showed great potential for extraction and purification of toxic and bioactive basic compounds from complex plant tissues.

Metal-Organic Gel-Modulated Synthesis of Hierarchically Porous Molecularly Imprinted Polymers for Efficient Removal of Sildenafil from Water.

Molecularly imprinted polymers (MIPs) with high specific recognition capability are promising in environmental remediation. However, traditional MIPs usually show poor specific binding affinity toward templates in pure aqueous medium, thus greatly limiting their practical applications in wastewater treatment. Herein, we proposed a facile and versatile method to synthesize a water-compatible hierarchically porous MIP (HP-MIP), in which a metal-organic gel (MOG) was formed by in situ assembly and acted as a removable structural modulator. Remarkably, the integration of the MOG modulator and template imprinting defects significantly improved the specific template binding affinity of HP-MIP in water. The adsorption behavior of HP-MIP fitted well with the heterogeneous Freundlich isotherm, suggesting that HP-MIP possessed greater site heterogeneity to sildenafil than HP-NIP, which confirmed the efficiency of HP-MIP for the removal of sildenafil from water. This approach provides an important pathway to prepare water-compatible porous MIP for efficient removal of highly toxic organic pollutants from wastewater.