Enzymatic inhibitive determination of AB-Fubinaca and AB-Pinaca on screen printed carbon tetratiofulvalene electrodes modified with nanoparticles and carbon nanotubes

Abstract

The rapid bio-sensing of the synthetic cannabinoids, AB-Fubinaca y AB-Pinaca, was developed and validated using six different electrode platforms. Screen-printed electrodes containing 3% tetrathiafulvalene (TTF) ink on the carbon electrode were modified with gold nanoparticles and carbon nanotubes. Then, acetylcholinesterase and glucuronyl transferase were immobilized on the surface of these carbon electrodes. A quantitative response was obtained by measuring the enzymatic inhibition caused by increasing concentrations of the target drugs. Acetylthiocholine iodide, serotonin, and β-D- phenolphthalein glucuronide were used as enzymatic substrates. Optimal pH, peak potential, and substrate concentration of each biosensor were studied. Analytical performance parameters and figures of merit, including LODs (< 1.5 × 10–4 mg/L), precision and reproducibility (< 10%), trueness (< 3%), demonstrate that the developed biosensors were able to interrogate low concentration of AB-Fubinaca y AB-Pinaca in a buffer environment. Michaelis Menten's apparent constants were estimated from inhibition calibration curves. They were lower than 2.0 × 10–3 M. Km inhibition values, and an interference study concluded which biosensor was the most selective for both drugs. AChE/AuNPs/SPCTTFEs with ATI, for AB-Fubinaca, pH = 7.00; ATI = 0.450 mM y Eap = +0.70 V; UDPGT/CNTNPs/SPCTTFEs with Serotonin substrate, AB-Pinaca, pH = 6.64; Cn Serotonin = 0.45 mM y Eap = +0.58 V. Performance parameters of the developed biosensors are acceptable as proof of concept, which opens an opportunity for their future application in forensic and chemical analysis.