Fuwei Wan

Molecularly imprinted polymeric microspheres for determination of bovine serum albumin based on flow injection chemiluminescence sensor.

A novel flow injection chemiluminescence (FI-CL) sensor for the determination of bovine serum albumin (BSA) using molecularly imprinted polymeric microspheres (MIPMs) as recognition element is reported. The BSA-MIPM was synthesized by suspension polymerization in toluene, using methacrylic acid (MAA) as functional monomer and ethylene glycol dimethacrylate (EGDMA) as cross-linker in the bovine serum albumin template molecule. Scanning electron microscope (SEM) was employed to characterize the surface morphology of the resultant imprinted microspheres. Molecular modeling was employed to simulate the possible recognition process of the MIPM. Then the synthesized BSA-MIPM was employed as recognition element by packing into flow cell to establish a novel FI-CL sensor. The chemiluminescence (CL) intensity was correlated linear with the concentration of BSA over the range of 1.0×10(-8) to 5.0×10(-6) g mL(-1) and the detection limit was 1.5×10(-9) g mL(-1). The relative standard deviation (RSD) for the determination of 1.0×10(-7) g mL(-1) BSA was 1.4% (n=11). The sensor is reusable and has a great improvement in sensitivity and selectivity for CL analysis. As a result, the new MIPM-CL sensor had been successfully applied to the determination of BSA in milk samples.

Monitoring of bovine serum albumin using ultrasensitive electrochemiluminescence biosensors based on multilayer CdTe quantum dots modified indium tin oxide electrodes

A novel method for the determination of bovine serum albumin (BSA) is proposed based on the electrochemiluminescence (ECL) of BSA with CdTe quantum dots (QDs) films. Thioglycolic acid (TGA) is used to cap CdTe colloidal solutions to obtain stable water-soluble QDs and intensive anodic ECL emission with a peak value starting from +1.2 V (vs.Ag/AgCl) in a carbonate bicarbonate buffer solution (pH 9.32) at an indium tin oxide (ITO) electrode. The ITO glass is modified with CdTe QDs by the layer-by-layer (LbL) self-assembly technique, which is immobilized into a homemade ECL flow chip and used as a receptor of the ECL sensor. The ECL intensity is correlated linearly with the concentration of BSA over the range of 1.0 × 10−9–1.0 × 10−6 g mL−1 and 1.0 × 10−6–1.0 × 10−5 g mL−1, and the detection limit is 5.48 × 10−10 g mL−1. The relative standard deviation is 1.62% for 4.0 × 10−7 g mL−1 BSA (n = 11). This simple and sensitive method reveals good reproducibility for ECL analysis. It puts forward a new efficient ECL method for the determination of BSA and opens new avenues for the application of QDs in ECL biosensors.

Detection of L‐phenylalanine using molecularly imprinted solid‐phase extraction and flow injection electrochemiluminescence

A novel flow injection electrochemiluminescence method combined with molecularly imprinted solid-phase extraction was developed for the determination of L-phenylalanine, in which

Flow injection electrochemiluminescence determination of L-lysine using tris(2,2′-bipyridyl) ruthenium(II) (Ru(bpy)32+) on indium tin oxide (ITO) glass

{\rm{Ru(bpy}})_3^{2 + }

Determination of thallium(III) with novel arsenoxylphenylazo rhodanine after pre-concentration and separation

was used as the luminophor and indium tin oxide glass was modified as the working electrode. Molecularly imprinted polymers, synthesized by self-assembly with functional monomer and crossing linker, were used for the selective extraction of L-phenylalanine. In order to overcome the drawbacks of traditional electrochemiluminescence cells such as high IR drop, high over-potential and so on, a novel electrochemiluminescence cell was developed. The enhanced electrochemiluminescence intensity was linearly related with the concentration of L-phenylalanine in the range from 1.0×10(-7) to 5.0×10(-5) g/mL with a detection limit of 2.59×10(-8) g/mL. The relative standard deviation for the determination of 1.0×10(-6) g/mL L-phenylalanine was 1.2% (n=11). The method showed higher sensitivity and good repeatability, and was successfully applied for the determination of L-phenylalanine in egg white, chicken and serum samples. A possible mechanism for the enhanced electrochemiluminescence response on indium tin oxide glass is proposed.

Preparation and application of electrochemiluminescence sensor for detecting trace pesticide residue

A flow injection electrochemiluminescence (FI-ECL) analysis method for the determination of L-lysine, in alkaline Na2CO3-NaHCO3 buffer solution, in the presence of tris(2,2′-bipyridyl) ruthenium(II) (Ru(bpy)32+) on indium tin oxide (ITO) glass was studied by conventional cyclic voltammetry. This method is based on the enhanced ECL of Ru(bpy)32+- L-lysine. Meanwhile, in order to overcome the drawbacks of conventional cells, a new ECL cell was designed. Under the optimal conditions, the enhanced ECL intensity was linearly related to the concentration of L-lysine in the range from 1.0 × 10−8 to 1.0 × 10−4 g mL−1 with a detection limit 1.43 × 10−9 g mL−1. The relative standard deviation (RSD) for the determination of 1.0 × 10−6 g mL−1L-lysine was 1.8% (n = 11). The possible mechanism is discussed. In this paper, the ECL behavior of Ru(bpy)32+ is studied on ITO glass, and the newly designed sensor is reusable, shows a great improvement in sensitivity and selectivity for ECL analysis, and can be successfully applied for amino acid analysis.

An electrochemiluminescence sensor for determination of durabolin based on CdTe QD films by layer-by-layer self-assembly

A new catalytic kinetic fluorescent method for determination of trace thallium(III) was investigated. The method was based on the catalytic effect of thallium on oxidation of 3-p-chlorophenyl-5-(2′-arsenoxylphenylazo) rhodanine (4ClRAAP) by hydrogen peroxide in potassium hydrogen phthalate-hydrochloric acid (pH = 5.2). Under the optimum conditions the great increase of fluorescence intensity had a linear relationship against the concentration of thallium in the range of 0.43 to 10.0 µg L−1 with a detection limit of 2.6 × 10−10 g L−1. The coexistent metal ions can be separated, and thallium can be enriched by polyamide, which greatly improved the selectivity and sensitivity of the system. The method was applied to determine trace amount of thallium in wine, water and mineral samples, with satisfactory results.