Changling Yan,Jin Li,Tingting Meng,Xun Liu,Ruixing Zhang,Yujuan Chen,Gongke Wang
A simple and reliable method was proposed for rapid detecting ciprofloxacin, based on molecularly imprinted technology. The molecularly imprinted ciprofloxacin hydrochloride (CPX) sensor was prepared by electropolymerization of pyrrole (Py) and o-phenylenediamine (o-PD) on the pencil graphite electrode (PGE). The performance of the sensor was characterized by square wave voltammetry (SWV) using potassium ferricyanide as molecular probe. Under optimal conditions, the sensor displayed high selectivity and stability towards CPX. A linear relationship between the change in current (Δi) and the logarithm of CPX concentrations from 1×10 −9 to 1×10 −3 mol/L was obtained with a detection limit of 7.58×10 −11 mol/L (S/N=3). Furthermore, the MIP sensor was applied for the analysis of real tablet samples with high accuracies.
Phthalates represent a potential risk for humans, since they are ubiquitous environmental contaminants. Efficient extraction and purification procedures are demanded for the detection of low concentration levels of phthalates. In this work, a novel type of molecularly imprinted polymers coated onto the surface of vinyl functionalized multi-walled carbon nanotubes was synthesized and coupled with gas chromatography–mass spectrometry (GC/MS) for the selective separation and determination of dioctyl phthalate (DOP) in beverage samples. The morphology, structure property, and thermostability of the resultant polymers were characterized by transmission electron microscopy, Fourier transform infrared spectroscopy, and thermogravimetric analysis. The adsorption properties of the prepared polymers were investigated by equilibrium rebinding and competitive experiments. The resultant imprinted nanomaterials exhibited high capacity and favorable selectivity. In addition, the feasibility of the developed method using the obtained imprinted polymers as a solid-phase sorbent coupled with GC/MS for the selective isolation and determination of DOP in different beverage samples was demonstrated. Under optimal conditions, the limit of detection of the proposed method for DOP was 2.3 ng L −1 . DOP spiked at three levels of concentration in beverage samples was extracted and determined through the application of the present method, with recoveries ranging from 88.6 to 93.0 % with relative standard deviations less than 5.6 %.
A simple glass/PDMS microfluidic chip for on-line sample pretreatment and contactless conductivity detection, which consisted of a 0.17 mm-thick glass cover and a PDMS substrate embedded with an SPE monolithic column, was presented in this paper. Using this integrated microchip system, sample extraction, injection, separation and detection were automatically performed in sequence. A sample of auramine O was concentrated by molecularly imprinted SPE (MISPE), eluted to sample reservoir, and injected by electromigration into separation channel for electrophoresis separation and contactless conductivity detection, with the calculated detection limit (S/N = 3) being 2.5 μg mL − 1 . The monolithic column was utilized to quantitatively extract auramine O , yielding an on-line enrichment factor of about 12. The microchip system is reliable and applicable to the analysis of auramine O in food sample.
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