Flexible Screen-Printed Electrochemical Sensors Functionalized with Electrodeposited Copper for Nitrate Detection in Water

Abstract

Nitrate (NO 3 – ) contamination is becoming a major concern due to the negative effects of an excessive NO 3 – presence in water which can have detrimental effects on human health. Sensitive, real-time, low-cost, and portable measurement systems able to detect extremely low concentrations of NO 3 – in water are thus becoming extremely important. In this work, we present a novel method to realize a low-cost and easy to fabricate amperometric sensor capable of detecting small concentrations of NO 3 – in real water samples. The novel fabrication technique combines printing of a silver (Ag) working electrode with subsequent modification of the electrode with electrodeposited copper (Cu) nanoclusters. The process was tuned in order to reach optimized sensor response, with a high catalytic activity toward electroreduction of NO 3 – (sensitivity: 19.578 μA/mM), as well as a low limit of detection (LOD: 0.207 nM or 0.012 μg/L) and a good dynamic linear concentration range (0.05 to 5 mM or 31 to 310 mg/L). The sensors were tested against possible interference analytes (NO 2 – , Cl – , SO 4 2– , HCO 3 – , CH 3 COO – , Fe 2+ , Fe 3+ , Mn 2+ , Na + , and Cu 2+ ) yielding only negligible effects [maximum standard deviation (SD) was 3.9 μA]. The proposed sensors were also used to detect NO 3 – in real samples, including tap and river water, through the standard addition method, and the results were compared with the outcomes of high-performance liquid chromatography (HPLC). Temperature stability (maximum SD 3.09 μA), stability over time (maximum SD 3.69 μA), reproducibility (maximum SD 3.20 μA), and repeatability (maximum two-time useable) of this sensor were also investigated.

On the role of graphene oxide in bifunctional Ni/MOF/rGO composites in electrochemical nitrate detection and oxygen evolution reaction

“…To understand the mechanism of the electrode reaction, the effect of scan rate on nitrate reduction is investigated by LSV. The reaction mechanism that takes place on the surface of the modified electrode is as follows: 41,95–97 NO 3 − + 2H + + 2e − → NO 2 − + H 2 O…”

“…7d shows the chronoamperometric response of the Ni-MOF/rGO modified electrode for OER in 1 M KOH solution at a constant potential of 1.23 V. The decay indicates a decrease in current within the first few hours of the scan before it reaches a steady-state and finally achieves a current density of 1.49 mA cm −2 after 24 h, which indicates the higher mass transportation and durability of the Ni-MOF/rGO catalyst. Many reports are available for electrocatalysts towards oxygen evolution reaction 72–98 as shown in Table S4 (ESI†). The electrochemical oxygen evolution reaction of the Ni-MOF/rGO electrocatalyst modified GCE is compared with that of other electrocatalyst systems.…”

Electroactive Core–Shell Chitosan-Coated Lanthanum Iron Oxide as a Food Freshness Level Indicator for Tyramine Content Determination

“…The observed relative peak current for tyramine in the presence of Mg 2+ , Ca 2+ , glucose, histamine, tryptophan, phenylalanine, and glutathione were depicted to be 93.114, 94.035, 93.261, 94.501, 93.586, 95.750, and 96.812%, respectively, which is quite better than the previous findings. 12,48,49 Thus, in the existence of the 400 CS/LFO-modified GCE, the observed change in the response of peak current was noted to be 6.886% for Mg 2+ , 5.965% for Ca 2+ , 6.739% for glucose, 5.499% for histamine, 6.414% for tryptophan, 4.25% for phenylalanine, and 3.188% for glutathione and hence offered satisfactory selectivity and anti-interference ability toward tyramine detection.…”

An Aptasensor Based on a Flexible Screen-Printed Silver Electrode for the Rapid Detection of Chlorpyrifos

“…Figure 1 shows the sensor structure consisting of an Ag (ECI 1011, LOCTITE E&C) working electrode (WE) (diameter: 4 mm), an Ag counter electrode (CE), and an Ag/AgCl (ECI 1011, LOCTITE E&C) pseudo-reference electrode (RE). The three-electrode structure of the sensor was fabricated as described by Inam et al [ 43 ]. Subsequently, the electrodes were ultrasonically cleaned at room temperature in IPA and double-distilled water for 5 min using a bath sonicator (CP 104, Vetrotecnica S.r.l., Padova, Italy) [ 40 ].…”