MIP-Based Screen-Printed Potentiometric Cell for Atrazine Sensing

Abstract

This work presents the development of a MIP-based screen-printed potentiometric cell for sensing the pesticide atrazine. The cell comprises three screen-printed electrodes; the working and the counter are obtained by graphite-ink and the pseudo-reference by silver/silver chloride-ink. All electrodes are printed on the support of polyester. Obviously, only the working and the pseudo-reference electrodes are connected for potentiometric measurements. The prepolymeric mixture was composed of the reagents at the following molar ratio: 1 atrazine (ATZ):5 methacrylic acids (MAA):4 ethylene glycol dimethacrylate (EGDMA). An amount of 7 µL of the prepolymeric solution was drop coated on the graphite working electrode of the cell, and the polymerization was carried out in an oven at 70 °C overnight. The specific sites obtained after polymerization and template elution can be viewed as the ionophore of a usual ISE membrane. The active ion is the atrazine in its protonated form, positively charged, so the determination was carried out in aqueous solutions at pHs1.5. At these conditions, the potential increases linearly with atrazine concentration ranging from 5 × 10−7 to 5 × 10−6 M; the limit of detection obtained is 4 × 10−7 M. The slope of the calibration curve E vs. log c (obtained as an average value of the slope of different standardization performed with several electrodes) is 40(6) mV/dec; the sub-Nernstian behavior can be ascribed to the interference of the anions present in the solution media.

Potentiometric MIP-Modified Screen-Printed Cell for Phenoxy Herbicides Detection

“…The surface of the working electrode was functionalized by a MIP layer to obtain a selective sensor. The pre-polymeric mixture molar ratio was defined according to previous studies [ 56 ]. The volume selected for drop-coating was 7 µL, i.e., a quantity enough to cover the working electrode and keep the pseudo-reference and the counter electrodes unaltered.…”

“…Potentiometric and, more in general, all electrochemical techniques have several advantages compared to the classic ones: the instrumentation is less expensive, the time of analysis is low, the apparatus may be portable, the sensors can be used for in situ measurements, and the surface of the electrodes can be modified in order to obtain more specific and sensitive detections. In particular, the electrodic surface can be activated with different kinds of modifiers such as multi-Walled carbon nano tubes (MWCNTs) [ 20 , 21 , 22 , 23 , 24 , 25 ], metal nano particles (NPs) [ 26 , 27 , 28 , 29 , 30 , 31 ], graphene [ 32 , 33 , 34 , 35 , 36 , 37 ], metal organics frameworks (MOFs) [ 38 , 39 , 40 , 41 , 42 , 43 ] in order to enhance the sensitivity, aptamers, antibodies [ 44 , 45 , 46 , 47 , 48 , 49 ], enzymes [ 50 , 51 , 52 , 53 , 54 , 55 ], or molecularly imprinted polymers (MIPs) [ 56 , 57 , 58 , 59 , 60 , 61 ] to improve the selectivity.…”

“…In this context, the present study aims to develop a MIP-based screen-printed potentiometric cell to detect phenoxy herbicides using MCPA as a template molecule. The sensor is prepared according to a previously developed procedure [ 56 ] schematized in Figure 2 . The MIP-modified working electrode acts as an ion-selective electrode, so the solution pH required for the measurements has to be selected in a range in which MCPA is negatively charged.…”

Towards miniaturized electrochemical sensors for monitoring of polychlorinated biphenyls

“…The sensors attained detection limit in femtomolar owing to the enhanced selectivity from MIPs 57 , reporting results similar to those of the earlier reported aptasensor for PCBs 32 . MIP-based screen printed electrode sensor for atrazine, another chlorinated molecule, has also been reported with detection limit of 0.4 µM 58 . A highly selective MIP-based sensor for chloramphenicol that combined MIPs with carbon nanotubes reported a detection limit of 10 nM 34 .…”

Application of ionic liquids and various carbon materials in reference electrodes with carbon paste‐based transducers

“…As the use of aqueous electrolyte is impractical in miniature electrodes, the simplest solution is to employ quasi-reference Ag/AgCl electrode, that is to use sample solution as an reference electrolyte. This attempt has been extensively used in many potentiometric devices, due to the possibility of screen-printing or inkjet-printing of Ag/ AgCl paste [15,16]. However, the major drawback of such RE is that potential of Ag/AgCl electrode depends on chloride activity.…”