A Simple and Efficient Molecularly Imprinted Electrochemical Sensor for the Selective Determination of Tryptophan

Abstract

In this paper, a tryptophan (Trp) molecularly imprinted chitosan film was prepared on the surface of an acetylene black paste electrode using chitosan as the functional polymer, Trp as the template molecule and sulfuric acid as the crosslinking agent. The surface morphologies of non-imprinted and imprinted electrodes were characterized by scanning electron microscopy (SEM). The formation of hydrogen bonds between the functional polymer and the template molecule was confirmed by infrared spectroscopy. Some factors affecting the performance of the imprinted electrode such as the concentration of chitosan, the mass ratio of chitosan to Trp, the dropping amount of the chitosan-Trp mixture, the solution pH, and the accumulation potential and time were discussed. The experimental results show that the imprinted electrode exhibit good affinity and selectivity for Trp. The dynamic linear ranges of 0.01–4 M, 4–20 M and 20–100 M were obtained by second derivative linear sweep voltammetry, and the detection limit was calculated to be 8.0 nM. The use of the imprinted electrode provides an effective method for eliminating the interference of potentially interfering substances. In addition, the sensor has high sensitivity, reproducibility and stability, and can be used for the determination of Trp in pharmaceutical preparations and human serum samples.

Sensitive Voltammetric Sensor for Tryptophan Detection by Using Polyvinylpyrrolidone Functionalized Graphene/GCE

“…The electrochemical behavior of Trp at different electrodes was studied by second derivative linear sweep voltammetry. Compared with CV, differential pulse voltammetry (DPV) and square wave voltammetry (SWV), SDLSV has the advantages of stable baseline and sharp peak shape, which helps to improve the sensitivity and selectivity of quantitative analysis [19,20]. Figure 3 exhibitsSDLSVs of 10 µM Trp obtained at different electrodes.…”

“…However, direct oxidation of Trp on the bare electrode is not attractive because of slow electron transfer and high overpotential, as well as poor repeatability due to the fouling effect. In recent years, a lot of research work has been devoted to the introduction of new materials for electrode modification for Trp detection [11][12][13][14][15][16][17][18][19][20] (Table 1). However, there are still some disadvantages, such as low sensitivity or narrow linear range [14,17], highdetection limit [11,14], complexity [13][14][15], as well as the high cost of gold [12,17], will have an adverse effect on Trp detection.…”

Laser-Induced Graphene Electrodes Modified with a Molecularly Imprinted Polymer for Detection of Tetracycline in Milk and Meat

“…MIT has been widely used in separation, enrichment, and detection [ 25 ]. In fact, recently, MIP has been widely used as synthetic antibodies in electrochemical sensors due to their excellent selectivity, good physical and chemical stability, and low cost [ 26 ]. MIP forms a wide range of polymeric film for sensors, due to its simplicity and ease of preparation, stability, and reliability [ 27 ] and has been applied in sensors that mimic an antibody recognition due to its specific affinity and selectivity to the template [ 28 , 29 ].…”

Hydrophilic molecularly imprinted polymers functionalized magnetic carbon nanotubes for selective extraction of cyclic adenosine monophosphate from winter jujube

“…Chitosan (CS), a natural polysaccharide rich in amino and hydroxyl groups, has been considered as one of attractive functional materials due to its biodegradability, biocompatibility, and nontoxicity [27][28][29][30][31][32][33][34]. The water solubility of CS provides feasibility of synthesizing green MIPs in aqueous media, particularly for water soluble target [35].…”