Silicon Nitride Capacitive Chemical Sensor for Phosphate Ion Detection Based on Copper Phthalocyanine - Acrylate-polymer

International audienceIn this work, we report the development of a highly sensitive capacitance chemical sensor based on a copper C, C, C, C-tetra-carboxylic phthalocyanine-acrylate polymer adduct (Cu(II) TCPc-PAA) for phosphate ions detection. A capacitance silicon nitride substrate based Al-Cu/Si-p/SiO2/Si3N4 structure was used as transducer. These materials have provided good stability of electrochemical measurements. The functionalized silicon-based transducers with a Cu(II) Pc-PAA membrane were characterized by using Mott-Schottky technique measurements at different frequency ranges and for different phosphate concentrations. The morphological surface of the Cu(II) Pc-PAA modified silicon-nitride based transducer was characterized by contact angle measurements and atomic force microscopy. The pH effect was also investigated by the Mott-Schottcky technique for different Tris-HCl buffer solutions. The sensitivity of silicon nitride was studied at different pH of Tris-HCl buffer solutions. This pH test has provided a sensitivity value of 51 mV/decade. The developed chemical sensor showed a good performance for phosphate ions detection within the range of 10(-10) to 10(-5) M with a Nernstian sensitivity of 27.7 mV/decade. The limit of detection of phosphate ions was determined at 1 nM. This chemical sensor was highly specific for phosphate ions when compared to other interfering ions as chloride, sulfate, carbonate and perchlorate. The present capacitive chemical sensor is thus very promising for sensitive and rapid detection of phosphate in environmental applications

Silicon Nitride Capacitive Chemical Sensor for Phosphate Ion Detection Based on Copper Phthalocyanine – Acrylate-polymer

In this work, we report the development of a highly sensitive capacitance chemical sensor based on a copper C,C,C,C-tetra-carboxylic phthalocyanine-acrylate polymer adduct (Cu(II)TCPc-PAA) for phosphate ions detection. A capacitance silicon nitride substrate based AlCu/Si-p/SiO2/Si3N4 structure was used as transducer. These materials have provided good stability of electro- chemical measurements. The functionalized silicon-based transducers with a Cu(II)Pc-PAA membrane were characterized by using Mott-Schottky technique measurements at different frequency ranges and for different phosphate concentrations. The morphological surface of the Cu(II) Pc-PAA modified silicon-nitride based transducer was characterized by contact angle measurements and atomic force microscopy. The pH effect was also investigated by the Mott-Schottky technique for different Tris-HCl buffer solutions. The sensitivity of silicon nitride was e studied at different pH of Tris-HCl buffer solutions. This pH test has provided a sensitivity value of 51 mV/decade. The developed chemical sensor showed a good performance for phosphate ions detection within the range of 10-10 to 10-5 M with a Nernstian sensitivity of 27.7 mV/decade. The limit of detection of phosphate ions was determined at 1 nM. This chemical sensor was highly specific for phosphate ions when compared to other interfering ions as chloride, sulfate, carbonate and perchlorate. The present capacitive chemical sensor is thus very promising for sensitive and rapid detection of phosphate in environmental applications.Peer reviewe

Non-enzymatic disposable electrochemical sensors based on CuO/Co3O4@MWCNTs nanocomposite modified screen-printed electrode for the direct determination of urea

Abstract A new electrochemical impedimetric sensor for direct detection of urea was designed and fabricated using nanostructured screen-printed electrodes (SPEs) modified with CuO/Co3O4 @MWCNTs. A facile and simple hydrothermal method was achieved for the chemical synthesis of the CuO/Co3O4 nanocomposite followed by the integration of MWCNTs to be the final platform of the urea sensor. A full physical and chemical characterization for the prepared nanomaterials were performed including Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), contact angle, scanning electron microscope (SEM) and transmission electron microscopy (TEM). Additionally, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to study the electrochemical properties the modified electrodes with the nanomaterials at different composition ratios of the CuO/Co3O4 or MWCNTs. The impedimetric measurements were optimized to reach a picomolar sensitivity and high selectivity for urea detection. From the calibration curve, the linear concentration range of 10−12–10−2 M was obtained with the regression coefficient (R2) of 0.9961 and lower detection limit of 0.223 pM (S/N = 5). The proposed sensor has been used for urea analysis in real samples. Thus, the newly developed non-enzymatic sensor represents a considerable advancement in the field for urea detection, owing to the simplicity, portability, and low cost-sensor fabrication

Determination of prostate cancer biomarker acid phosphatase at a copper phthalocyanine-modified screen printed gold transducer

In this work, a novel sensor based on immobilised copper phthalocyanine, 2,9,16,23-tetracarboxylic acidpolyacrylamide (Cu(II)TC Pc-PAA) was developed for determination of acid phosphatase (ACP) levels in nanomolar quantities. Detection was based on the measurement of enzymatically generated phosphate, with initial studies focused on phosphate detection at a Cu(II)TC Pc-PAA modified screen-printed gold transducer. The sensor was characterised in relation to operational performance (pH, response time, stability, linearity, and sensitivity) and common anionic interferents (nitrate, sulphate, chloride, and perchlorate). The functionalised surface also facilitated rapid detection of the enzyme bi-product 2- naphthol over the range 5e3000 mM. Quantitation of ACP was demonstrated, realising a linear response range of 0.5e20 nM and LOD of 0.5 nM, which is within the clinical range for this prostate cancer biomarker

Simultaneous determination of ascorbic acid, uric acid and dopamine using silver nanoparticles and copper monoamino-phthalocyanine functionalised acrylate polymer

A silver nanoparticle and copper monoamino-phthalocyanine-acrylate (Cu-MAPA) polymer modified glassy carbon electrode was developed for the simultaneous detection of dopamine (DOP), ascorbic acid (AA) and uric acid (UA) using voltammetric techniques. Silver nanoparticles (AgNPs) were synthesised according to the citrate reduction method. Following synthesis and characterisation the copper phthalocyanine polymer was co-deposited with AgNPs realising a surface with enhanced electron transfer which lowered the overpotential required for analyte electro-oxidation. Differential pulse voltammetry (DPV) was employed for the simultaneous determination of dopamine (DOP), ascorbic acid (AA) and uric acid (UA) at AgNP/Cu-MAPA modified surfaces at <μM ranges. The peak potential separations for DOP-AA and DOP-UA were ca. 181 mV and 168 mV respectively. The chemical sensor was also capable of individual quantitation of DOP, UA and AA with detection limits of 0.7, 2.5 and 5.0 nM respectively. Overall, the approach realised a simple and effective electrode modifier for the selective discrimination and quantitation of DOP in the presence of physiological levels of AA and UA

Development of a Perchlorate Chemical Sensor Based on Magnetic Nanoparticles and Silicon Nitride Capacitive Transducer

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Development of a perchlorate sensor based on Co-phthalocyanine derivative by impedance spectroscopy measurements

International audienceIn this work, we have prepared a perchlorate sensor based on cobalt phthalocyanine derivative molecules. The membrane was deposited onto gold substrates using dip-coating method. Adhesion and morphological properties have been studied using contact angle measurements. Then, the sensitivity, the detection range and the detection limit were determined using electrochemical impedance spectroscopy (EIS) measurements. The sensor was also studied specificity towards interfering ions nitrate (NO3-), carbonate (CO32-) and sulfate (SO42-) to show the specificity of the membrane. The impedance behavior of the perchlorate sensor (gold/membrane) has been modeled by an equivalent electrical circuit using a modified Randles model for better understanding the phenomena present at the interface membrane/electrolyte

Novel Amperometric Mercury-Selective Sensor Based on Organic Chelator Ionophore

A novel amperometric sensor for the direct determination of toxic mercury ions, Hg2+, based on the organic chelator ionophore N, N di (2-hydroxy-5-[(4-nitrophenyl)diazenyl]benzaldehyde) benzene-1,2-diamine (NDBD), and multiwalled carbon nanotubes (MWCNT) immobilized on a glassy carbon electrode surface was developed. The parameters influencing sensor performance including the ionophore concentration, the applied potential, and electrolyte pH were optimized. The sensor response to Hg2+ was linear between 1-25 µM with a limit of detection of 60 nM. Interferences from other heavy metal ions were evaluated and the sensor showed excellent selectivity towards Hg2+. The method was successfully applied to the determination of mercury ions in milk and water samples

Electrocatalytic Nitrite Determination Using Iron Phthalocyanine Modified Gold Nanoparticles

lectrochemical detection of nitrite was achieved via electrodeposition of gold nanoparticles (AuNPs) onto glassy carbon electrodes, followed by 3‐mercaptopropionic acid (MPA) self‐assembly, enabling attachment of an iron(III) monoamino‐phthalocyanine (FeMAPc) catalyst via amide bond formation. The use of scanning electron microscopy, energy dispersive X‐ray spectroscopy and ultraviolet‐visible spectroscopy realised surface characterisation while cyclic voltammetry and electrochemical impedance spectroscopy techniques were applied for electrochemical interrogation. The electrochemical behaviour of nitrite at the bare (GCE), AuNPs/GCE, FeMAPc/GCE and FeMAPc‐MPA/AuNPs/GCE was further scrutinised using differential pulse voltammetry in phosphate buffer solution (0.1 M PBS, pH 5.8). Overall the FeMAPc‐MPA/AuNPs/GCE resulted in sensitivity 14.5 nA/µM, which was double that of AuNPs/GCE, 2.4 times FeMAPc/GCE and 3.5 times the response at a bare GCE, with linear range 1.9 µM–2.04 mM (PBS, pH 5.8) and LOD 0.21 µM. An interference study revealed that the proposed sensor (FeMAPc‐MPA/AuNPs/GCE) exhibited a selective response in the presence of interfering anions and the analytical capability of the sensor was demonstrated via nitrite ion determination in real water samples