Amperometric Environmental Phosphate Sensors

Abstract

We report a novel amperometric sensor for aqueous phosphate ions in freshwater systems based on the reductive square wave voltammetry of molybdate(VI) anions immobilized within a chitosan matrix deposited on a glassy carbon electrode. A sensitivity of 4.4 ± 0.1 μA/μM was realized together with a LOD of 0.15 μM. The sensor was insensitive to chloride and nitrate ions below a threshold concentration of 1.0 mM. Analytical measurements were successfully made in authentic samples of tap and pond water.

Portable All-in-One Electrochemical Actuator-Sensor System for the Detection of Dissolved Inorganic Phosphorus in Seawater

“…Importantly, an excess of molybdate can ensure the formation of phosphomolybdate ions by shifting the equilibrium described in eq 1 toward the products. 11 The phosphomolybdate complex is known to exhibit two pairs of characteristic redox peaks at pH ≤ 2, and the associated electrochemistry appears to be governed by its adsorption onto the electrode surface. 11,15−17 Overall, different Mo units are converted between the +6 and +5 redox states, as shown in eqs 7 and 8.…”

“…However, cross-selectivity and the pH dependence of the response often impede the detection of all P species. In addition, the limit of detection (LOD) is higher than the minimum requirements for unpolluted waters (traditional LODs ≥ 10 μM). − On the other hand, once formed via the molybdate reaction described in eq , the phosphomolybdate complex can be reduced via electrochemistry without the need for a reducing agent in the solution . Moreover, Fogg et al proposed the use of differential pulse voltammetry (DPV) in mixed water/organic solvents (e.g., water/acetone).…”

Efficient Electrochemical Microsensor for In Vivo Monitoring of H2O2 in PD Mouse Brain: Rational Design and Synthesis of Recognition Molecules

“…Considering that the number of the probes on the electrode is significant to their electrochemical performance, we first calculated the surface coverage (Γ) of DBP derivatives on the electrode using Γ = Q/(nFA). 42 As summarized in Table S1, the substitution of the meta-site of benzene boric acid ester with either electron-drawing (−Cl, −F) or electronpulling (−OCH 3 ) groups had a surface coverage comparable to that of DBP. Under this circumstance, the E p values of m-F-DHP (0.432 V) and m-Cl-DHP (0.365 V) were more positive than that of DHP (0.308 V), whereas m-OCH 3 -DHP (0.298V) demonstrated the opposite (Figure 2F), which indicated that m-F-DHP and m-Cl-DHP were more difficult to be oxidized on the electrode.…”

“…Regarding this process, we further compared the typical parameters, including the peak potential ( E p ) and heterogeneous electron-transfer rate ( k s ) of the obtained DHP derivatives. Considering that the number of the probes on the electrode is significant to their electrochemical performance, we first calculated the surface coverage (Γ) of DBP derivatives on the electrode using Γ = Q /( nFA ) . As summarized in Table S1, the substitution of the meta -site of benzene boric acid ester with either electron-drawing (−Cl, −F) or electron-pulling (−OCH 3 ) groups had a surface coverage comparable to that of DBP.…”

An excited state intramolecular proton transfer induced phosphate ion targeted ratiometric fluorescent switch to monitor phosphate ions in human peripheral blood mononuclear cells

“…8 In this regard, the fluorescent switch behaves as a promising tool for sensing trace amounts of chemical and biological samples. 9 Although a few electrochemical sensors are able to detect PO 4 3− /HPO 4 2− successfully, 10 the design of optical chemosensors which are able to recognize specifically PO 4 3− /HPO 4 2− in human PBMCs has rarely been investigated. Phosphate has also some damaging effects on the environment and it shows poisonous effects on human health by damaging various organs, such as, impaired renal function, harmful vascular calcification etc .…”