Nanomaterials Based Sensors for Acetaminophen and Dopamine Detection

1. Nanomaterials Based Sensors for Acetaminophen and Dopamine Detection Luminiţa Fritea, Cecilia Cristea, Mihaela Tertiş, Oana Hosu, Robert Săndulescu Analytical Chemistry Department, Faculty of Pharmacy, “Iuliu Haţieganu” University of Medicine and Pharmacy, Pasteur 4 Cluj-Napoca, Romania, rsandulescu@umfcluj.ro Different types of electrochemical biosensors are reported based on nanomaterials like carbon nanotubes (SWCNT), graphenes, cyclodextrines (β-CD) and conductive polymers (polyethylenimine - PEI). Two model molecules, acetaminophen and dopamine were detected with those biosensors. A. Acetaminophen biosensor based on carbon nanotubes and horseradish peroxidase (HRP) B. Dopamine biosensor with graphene and tyrosinase (PPO) • Schematic representation for the development of acetaminophen and dopamine biosensors Acetaminophen Dopamine (D) • Electrochemical characterization of modified glassy carbon electrodes and biosensors optimization (E) (B) (A) (A) (B) Correlation between Nyquist plots for: (A) bare GCE and (B) SWCNT+PEI+HRP modified GCE in 10 mM K3[Fe(CN)6] + K4[Fe(CN)6], in phosphate buffer (0.1 M; pH 7.4). Amplitude: 10 mV, first frq 100 kHz last frq 10 mHz. Fitting results are given by lines. Inset: the equivalent circuits used . • SWVs registered on: bare GCE (a); PPO(1mg/ml)+PEI(1mg/ml) (1 layer) modified GCE (b); β-CD(1mg/ml)(1 layer)+ PPO +PEI (1 layer)/GCE (c); PPO+PEI(1 layer) GO (LBL; 3 layers)/GCE (d); β-CD(1layer)+ PPO +PEI(1 layer) g GO (LBL; 3 layers)/GCE (e) in the presence of 1 mM dopamine solution in PB solution (0.1M; pH 7.2). • EIS spectra (61 frq. 100kHz -10 mHz; amplitude: 0.01 V)registered for: bare GCE (a); and modified with: graphene oxide (GO) by spin coating (b); GO through layer by layer deposition - 3 layers(c) and GCE modified with GO through LBL deposition and β-CD (d) in the presence of 10 mM [Fe(CN)6]3-/4- in PBS (0.1 M; pH 7.2); • Biosensor testing - amperometry (A) (B) LOD: 10.42 μM LDR: 30-2500 μM LOD: 1.36–8.09 μM LDR: 4 - 80 μM; 20 - 160 μM Amperometricresponse for dopamineon β-CD+PPO+PEI-GO/GCE (a) and bare GCE (b); tyrosinase concentration:1 mg/mL; PEI 1mg/mL; Amperometric response for acetaminophen on GCE (d=1 mm) modified with HRP/SWCNT/PEI film; HRP concentration: 0.3 mg mL-1 and 0.6 mg mL-1 in PEI 1 mg mL-1 • Real sample analysis – acetaminophen determination in pharmaceutical products Measurement results for acetaminophen in pharmaceutical samples • CONCLUSIONS • The combination of different types of nanomaterials (CNTs, graphenes, cyclodextrins) and polymers as immobilization platform with different bioreceptors reveals enhanced electroanalytical performances of the sensors in the pharmaceutical and biomedical analysis. • The obtained biosensors present good sensitivity and selectivity for the detection of various pharmaceuticals. This paper was elaborated under the frame of European Social Found, Human Resources Development Operational Programme 2007-2013, projects no. POSDRU/159/1.5/S/138776 and 159/1.5/S/136893. The authors are grateful for the financial support to the Romanian National Authority for Scientific Research, CNCS - UEFISCDI, project number PN-II-ID-PCE-2011-3-0355. The acetaminophen indirect detection mechanism – catalytic peroxydation through HRP