Atrazine, sensor

Shoji, R., T. Takeuchi, and I. Kubo (2003). Atrazine sensor based on molecularly imprinted polymer-modified gold electrode. Anal. Chem., 75(18) 4882-4886. 

Using diethyl aminoethylmethacrylate and ethylene glycol dimethacrylate, atrazine selective membranes were produced and incorporated into an atrazine sensor [125]. Atrazine could be detected over the range 0.01-0.50 mg/L with a response time of 30 mins and, most importantly, the sensors did not show loss of sensitivity over a four month period. Selective membrane diffusion of adenosine over guanosine was achieved using a membrane imprinted with 9-ethyladenine [126] and other selective membranes have also been prepared [127,128],... 

Pribyl, J., Hepel, M., Halamek, J., and Skladal, P. (2003) Development of piezoelectric immunosensors for competitive and direct determination of atrazine. Sensors and Actuators B-Chemical 91,33 3-341... 

Figure 15.11 Sensor response to herbicide concentration obtained with a polymer imprinted with atrazine. Reprinted from Sergeyeva et al. (1999). Copyright 1999 Elsevier Science.

Sergeyeva TA, Piletsky SA, Brovko AA, Slinchenko EA, Sergeeva LM, El skaya AV. Selective recognition of atrazine by molecularly imprinted polymer membranes. Development of conductometric sensor for herbicides detection. Anal Chim Acta 1999 392 105-111. 

Another nice example of nanostructuring an MIP layer is the work published by Wu et al. [138, 139] who developed a label-free optical sensor based on molecularly imprinted photonic polymers. Photonic crystals were prepared by self-assembly of silica nanospheres. The space between the spheres was then filled with MIP precursor solution. After polymerization, the silica was dissolved, leaving an MIP in the form of a 3D-ordered interconnected macroporous inverse polymer opal (Fig. 15). The authors were able to detect traces of the herbicide atrazine at low concentrations in aqueous solution [139]. Analyte adsorption into the binding sites resulted in a change in Bragg diffraction of the polymer characterized by a color modification (Fig. 15). 

Atrazine in solution Methacrylic acid (MAA) or DEAEM M IP-based conductimetric sensor 0.01 mg/L Piletsky et al., 1995... 

A new chemical sensor based on surface transverse device has been developed (99) (see Sensors). It resembles a surface acoustic wave sensor with the addition of a metal grating between the tranducer and a different crystal orientation. This sensor operates at 250 mHz and is ideally suited to measurements of surface-attached mass under fluid immersion. By immobilizing atrazine to the surface of the sensor device, the detection of atrazine in the range of 0.06 ppb to 10 ppm was demonstrated. 

Figure 1. QCM sensor response of an atrazine-imprinted polyactylic acid towards a pulse of 3 ppb atrazine in water.

During the last decade the number of application of MIP-based sensors has increased dramatically. The high selectivity and affinity of MIPs for target analytes make them ideal recognition elements in the development of sensors. Capacitive (Panasyuk etal., 2001), conductimetric (Piletsky et al., 1995), field effect (Lahav et al., 2004), amper-ometric (Kritz and Mosbach, 1995), and voltammetric (Pizzariello et al., 2001), electrochemical transduction systems have been used. Sensors based on conductimetric transduction have been developed by Piletsky et al. (1995) for the analysis of herbicides. A system using a TiC>2 sol-gel system, and with a linear range of 0.01-0.50 mg L-1 for atrazine, without interference of simazine, and chloroaromatic acids has been described by Lahav et al. (2004). 

Fig. 5. Example of competitive and displacement assays. (A) Competitive assay of atrazine, binding curves obtained for mixtures of MAb (ascites fluid, 1,000x diluted) preincubated for 15 min with variable concentrations of atrazine. (B) Displacement of antibody from the sensor in the presence of increasing concentrations of the analyte -peptide representing a surface epitope of the antigen. The antigen-modified sensor was preincubated with antibody (not shown), thus a constant amount of immunocomplexes (fa 350 Hz) was present before starting each of the measurements.

With regard to substrate-selective sensors with pre-organized cavities, impressive advances have been made in molecular imprinting [55-57]. The discovery of MIP-membrane electro conductivity was an interesting issue, which actually led to the appearance of the earliest MIP sensors [58,59]. It was shown that the membrane electroconductivity could be a function of the interaction between MIP-membrane and ligand (i.e., imprint species) (Fig. 5). An increase in the ligand concentration would result in an enhancement of membrane conductivity. With the same level of concentration, a maximal electro conductivity with the imprint species could be achieved. In addition, it has also been confirmed that polymers imprinted with amino acids, nucleosides, atrazines, sialic acids, or cholesterols can show similar features if coupled with the appropriate transducer [60-64], In particular, molecular imprinting is presently probably the only choice when no suit-... 

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