Capacitive sensing of N-formylamphetamine based on immobilized molecular imprinted polymers

Abstract

A highly sensitive, capacitive biosensor was developed to monitor trace amounts of an amphetamine precursor in aqueous samples. The sensing element is a gold electrode with molecular imprinted polymers (MIPs) immobilized on its surface. A continuous-flow system with timed injections was used to simulate flowing waterways, such as sewers, springs, rivers, etc., ensuring wide applicability of the developed product. MIPs, implemented as a recognition element due to their stability under harsh environmental conditions, were synthesized using thermo- and UV-initiated polymerization techniques. The obtained particles were compared against commercially available MIPs according to specificity and selectivity metrics; commercial MIPs were characterized by quite broad cross-reactivity to other structurally related amphetamine-type stimulants. After the best batch of MIPs was chosen, different strategies for immobilizing them on the gold electrode's surface were evaluated, and their stability was also verified. The complete, developed system was validated through analysis of spiked samples. The limit of detection (LOD) for N-formyl amphetamine was determined to be 10μM in this capacitive biosensor system. The obtained results indicate future possible applications of this MIPs-based capacitive biosensor for environmental and forensic analysis. To the best of our knowledge there are no existing MIPs-based sensors toward amphetamine-type stimulants (ATS).

Molecularly Imprinted Polymers (MIPs) in Sensors for Environmental and Biomedical Applications: A Review

“…However, the LOD and LOQ were too high, above the typical concentrations of phosphate in wastewater. N -formylamphetamine, an intermediate and an indicator of amphetamine synthesis, was detected in wastewaters using MIP particles that were obtained on the gold surface of a wafer electrode, with a mixture of two functional monomers, HEMA and IA, along with EGDMA, in a reaction started with AIBN at 60 °C [ 136 ]. The monomers contained methylene and carbonyl groups to bond to the phenyl and amide groups of the template.…”

Recent developments in electrochemical detection of illicit drugs in diverse matrices

“…This introduced free carboxyl groups on the exterior surface of the MIP which can interact both electrostatically and covalently with an amine group. Therefore tyramine was selected as the linker (Graniczkowska et al, 2016).…”

“…With such sensor, real-time monitoring of the binding effect is possible. Results could be drawn after 7-8 min, taken the death time from the sample transport to the flow cell into account (Graniczkowska et al, 2016). A capacitive aptasensor was developed by Oueslati et al (2018) for the detection of cocaine in blood serum.…”

Capacitive sensing of an amphetamine drug precursor in aqueous samples: Application of novel molecularly imprinted polymers for benzyl methyl ketone detection

“…To the best of our knowledge, this is the first manuscript describing MIPs towards BMK and one of a few works devoted to electrochemical MIP-based detection of ATS. Indeed, a highly sensitive, MIP-based capacitive sensor was developed by our group to monitor trace amounts of NFA in aqueous samples with a linear working range of 50-250 µM and an LOD of 50 µM (Graniczkowska et al, 2016). More recently, a square wave voltammetric sensor, was developed for MDMA detection in blood serum and urine.…”