Evaluation of amperometric dot microsensors for the analysis of folic acid in pharmaceutical tablets and urine samples

2015 ◽  
Vol 19 (05) ◽  
pp. 679-687 ◽  
Author(s):  
Ramona Georgescu ◽  
Jacobus Frederick van Staden ◽  
Raluca-Ioana Stefan-van Staden ◽  
Cristian Boscornea
Keyword(s):  
Folic Acid ◽  
Limit Of Detection ◽  
Supporting Electrolyte ◽  
Differential Pulse ◽  
Urine Samples ◽  
Pharmaceutical Tablets ◽  
Pulse Voltammetry ◽  
Optimum Working ◽  
Selection Of ◽  
Linear Concentration

Nineteen amperometric dot microsensors based on graphite and graphene modified with a selection of porphyrins and phthalocyanines were evaluated and tested for their ability of the analysis of folic acid in pharmaceutical tablets (e.g. Acifol) and biological samples (e.g. urine), using differential pulse voltammetry. Cyclic voltammetry was used to optimize the working conditions, e.g. pH and electrolyte for the proposed amperometric dot microsensors. The optimum working pH was 7.0 (phosphate buffer), with a 0.1 M potassium chloride supporting electrolyte. The linear concentration ranges for folic acid were between 10-6 and 10-3) M for all dot microsensors except dot microsensors based on graphite modified with tetraamino cobalt(II) phthalocyanine and tetranitro manganese(II) phthalocyanine which had linear concentration ranges between 10-6 and 10-4 M . The highest sensitivity (0.770 nA. mmolL-1) was recorded for the graphite modified with tetraamino cobalt(II) phthalocyanine based dot sensor and the lowest limit of detection (1.14 10-7 M ) for the graphite modified with tetranitro zinc(II) phthalocyanine based dot sensor. The dot sensors were used for the reliable analysis of folic acid in Acifol tablets and urine samples, with recoveries higher than 94.00% and 99.00%, respectively.

scholarly journals An efficient electrochemical sensing of hazardous catechol and hydroquinone at direct green 6 decorated carbon paste electrode

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
K. Chetankumar ◽  
B. E. Kumara Swamy ◽  
S. C. Sharma ◽  
S. A. Hariprasad
Keyword(s):  
Carbon Paste Electrode ◽  
Limit Of Detection ◽  
Tap Water ◽  
Differential Pulse ◽  
Electrochemical Sensing ◽  
Carbon Paste ◽  
Pulse Voltammetry ◽  
Two Peaks ◽  
Paste Electrode ◽  
Scanning Electron

AbstractIn this proposed work, direct green 6 (DG6) decorated carbon paste electrode (CPE) was fabricated for the efficient simultaneous and individual sensing of catechol (CA) and hydroquinone (HY). Electrochemical deeds of the CA and HY were carried out by cyclic voltammetry (CV) and differential pulse voltammetry (DPV) at poly-DG6-modfied carbon paste electrode (Po-DG6-MCPE). Using scanning electron microscopy (SEM) studied the surface property of unmodified CPE (UCPE) and Po-DG6-MCPE. The decorated sensor displayed admirable electrocatalytic performance with fine stability, reproducibility, selectivity, low limit of detection (LLOD) for HY (0.11 μM) and CC (0.09 μM) and sensor process was originated to be adsorption-controlled phenomena. The Po-DG6-MCPE sensor exhibits well separated two peaks for HY and CA in CV and DPV analysis with potential difference of 0.098 V. Subsequently, the sensor was practically applied for the analysis in tap water and it consistent in-between for CA 93.25–100.16% and for HY 97.25–99.87% respectively.

scholarly journals Supramolecular assemblies of carbon nanocoils and tetraphenylporphyrin derivatives for sensing of catechol and hydroquinone in aqueous solution

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Syeda Aqsa Batool Bukhari ◽  
Habib Nasir ◽  
Lujun Pan ◽  
Mehroz Tasawar ◽  
Manzar Sohail ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Linear Trend ◽  
Differential Pulse ◽  
Peak Potential ◽  
Limit Of Quantification ◽  
Efficient Detection ◽  
Good Repeatability ◽  
Ft Ir ◽  
Pulse Voltammetry

AbstractNon-enzymatic electrochemical detection of catechol (CC) and hydroquinone (HQ), the xenobiotic pollutants, was carried out at the surface of novel carbon nanocoils/zinc-tetraphenylporphyrin (CNCs/Zn-TPP) nanocomposite supported on glassy carbon electrode. The synergistic effect of chemoresponsive activity of Zn-TPP and a large surface area and electron transfer ability of CNCs lead to efficient detection of CC and HQ. The nanocomposite was characterized by using FT-IR, UV/vis. spectrophotometer, SEM and energy dispersive X-ray spectroscopy (EDS). Cyclic voltammetry, differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy were used for the electrochemical studies. CNCs/Zn-TPP/GCE nanosensor displayed a limit of detection (LOD), limit of quantification (LOQ) and sensitivity for catechol as 0.9 µM, 3.1 µM and 0.48 µA µM−1 cm−2, respectively in a concentration range of 25–1500 µM. Similarly, a linear trend in the concentration of hydroquinone detection was observed between 25 and 1500 µM with an LOD, LOQ and sensitivity of 1.5 µM, 5.1 µM and 0.35 µA µM−1 cm−2, respectively. DPV of binary mixture pictured well resolved peaks with anodic peak potential difference, ∆Epa(CC-HQ), of 110 mV showing efficient sensing of CC and HQ. The developed nanosensor exhibits stability for up to 30 days, better selectivity and good repeatability for eight measurements (4.5% for CC and 5.4% for HQ).

Determination of Diclofenac in Urine Samples by Molecularly-Imprinted Solid-Phase Extraction and Adsorptive Differential Pulse Voltammetry

2007 ◽  
Vol 19 (15) ◽  
pp. 1555-1561 ◽  
Author(s):  
Laura Fernández-Llano ◽  
M. Carmen Blanco-López ◽  
M. Jesús Lobo-Castañón ◽  
Arturo J. Miranda-Ordieres ◽  
Paulino Tuñón-Blanco
Keyword(s):  
Solid Phase Extraction ◽  
Differential Pulse Voltammetry ◽  
Solid Phase ◽  
Differential Pulse ◽  
Urine Samples ◽  
Phase Extraction ◽  
Molecularly Imprinted ◽  
Pulse Voltammetry

scholarly journals Electrochemical Nanocomposite Single-Use Sensor for Dopamine Detection

Sensors ◽  
2019 ◽  
Vol 19 (14) ◽  
pp. 3097 ◽  
Author(s):  
Giulia Selvolini ◽  
Cinzia Lazzarini ◽  
Giovanna Marrazza
Keyword(s):  
Limit Of Detection ◽  
Differential Pulse ◽  
Sensor Response ◽  
Sensor Surface ◽  
Serum Samples ◽  
Dopamine Detection ◽  
Sensitive Sensor ◽  
Single Use ◽  
Pulse Voltammetry ◽  
Nanocomposite Sensor

In this work, we report the development of a simple and sensitive sensor based on graphite screen-printed electrodes (GSPEs) modified by a nanocomposite film for dopamine (DA) detection. The sensor was realized by electrodepositing polyaniline (PANI) and gold nanoparticles (AuNPs) onto the graphite working electrode. The sensor surface was fully characterized by means of the cyclic voltammetry (CV) technique using [Fe(CN)6]4−/3− and [Ru(NH3)6]2+/3+ as redox probes. The electrochemical behavior of the nanocomposite sensor towards DA oxidation was assessed by differential pulse voltammetry (DPV) in phosphate buffer saline at physiological pH. The sensor response was found to be linearly related to DA concentration in the range 1–100 μM DA, with a limit of detection of 0.86 μM. The performance of the sensor in terms of reproducibility and selectivity was also studied. Finally, the sensor was successfully applied for a preliminary DA determination in human serum samples.

scholarly journals Determination of Atenolol and Trimetazidine in Pharmaceutical Tablets and Human Urine Using a High Performance Liquid Chromatography-Photo Diode Array Detection Method

2019 ◽  
Vol 2019 ◽  
pp. 1-8 ◽  
Author(s):  
Walaa El-Alfy ◽  
Omnia A. Ismaiel ◽  
Magda Y. El-Mammli ◽  
Abdalla Shalaby
Keyword(s):  
Human Urine ◽  
Limit Of Detection ◽  
Pure Form ◽  
Urine Samples ◽  
Dihydrogen Phosphate ◽  
Simple Liquid ◽  
Pharmaceutical Tablets ◽  
Limit Of Quantitation ◽  
Precision And Accuracy

A simple RP-HPLC-PDA method for determination of atenolol (ATN) and trimetazidine (TMZ) in human urine and tablets has been developed. Analytes were separated on a Caltrex BI column (125× 4.0 mm, 5 μm) with 25mM potassium dihydrogen phosphate pH 3.3, methanol, and acetonitrile mobile phases. The PDA detector was operated at 210 nm for TMZ and 225 nm for ATN and the flow rate was 1.0 mL/ min. Linearity was obtained over a concentration range of (1.0-100 μg/mL) for both analytes in standard solutions and the method was successfully applied for determination of target analytes in their pharmaceutical tablets. Excellent linearity was also obtained over concentration ranges of (0.25-25 μg/mL) and (0.5-25 μg/mL) in human urine for TMZ and ATN, respectively. A simple liquid-liquid extraction was applied for urine sample clean-up and a gradient method was used for chromatographic separation. The lower limit of quantitation (LOQ) was 0.99 and 0.60 μg/mL for ATN and TMZ, respectively. The limit of detection (LOD) was 0.30 and 0.18 μg/mL for ATN and TMZ, respectively. Inter- and intraday precision and accuracy for ATN were within ±1.89% in pure form and within ±2.85% in urine samples. Inter- and intraday precision and accuracy for TMZ were within ± 3.99% in pure form and within ± 3.19% in urine samples.

scholarly journals Development of a Label-Free Electrochemical Aptasensor for the Detection of Tau381 and its Preliminary Application in AD and Non-AD Patients’ Sera

Biosensors ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 84 ◽  
Author(s):  
Dan Tao ◽  
Bingqing Shui ◽  
Yingying Gu ◽  
Jing Cheng ◽  
Weiying Zhang ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Early Stage ◽  
Differential Pulse ◽  
Electrical Signal ◽  
Label Free ◽  
Modified Glassy Carbon Electrode ◽  
Serum Samples ◽  
Pulse Voltammetry ◽  
Aptamer Sensor ◽  
Preliminary Application

The electrochemical aptamer sensor has been designed for detecting tau381, a critical biomarker of Alzheimer′s disease in human serum. The aptasensor is obtained by immobilizing the aptamer on a carboxyl graphene/thionin/gold nanoparticle modified glassy-carbon electrode. As a probe and bridge molecule, thionin connected carboxyl graphene and gold nanoparticles, and gave the electrical signal. Under optimal conditions, the increment of differential pulse voltammetry signal increased linearly with the logarithm of tau381 concentration in the range from 1.0 pM to 100 pM, and limit of detection was 0.70 pM. The aptasensor reliability was evaluated by determining its selectivity, reproducibility, stability, detection limit, and recovery. Performance analysis of the tau381 aptasensor in 10 patients’ serum samples showed that the aptasensor could screen patients with and without Alzheimer′s disease. The proposed aptasensor has potential for use in clinically diagnosing Alzheimer′s disease in the early stage.

Sensitive Determination of Epinephrine in the Presence of Ascorbic Acid at Poly(diphenylamine sulfonic acid) Modified Sensor

2020 ◽  
Vol 18 (4) ◽  
pp. 253-258
Author(s):  
Gamze Erdoğdu
Keyword(s):  
Ascorbic Acid ◽  
Sulfonic Acid ◽  
Limit Of Detection ◽  
Phosphate Buffer Solution ◽  
Differential Pulse ◽  
Buffer Solution ◽  
Sensitive Determination ◽  
Pulse Voltammetry ◽  
Modified Sensor

A sensitive and simple modified sensor was prepared by electrodeposition of diphenylamine sulfonic acid (DPSA) to the glassy carbon electrode surface by cyclic voltammetry (CV) technique. The electrooxidation of epinephrine (EP) was accomplished by CV and differential pulse voltammetry at poly(DPSA) modified sensor. As a result of the findings, the current values were enhanced and both substances were separated at the modified sensor compared to the bare electrode. There was linearly between the oxidation current and concentration of EP from 0.2 to 100 μM in phosphate buffer solution at pH 7.0. The limit of detection was 5.0 nM and the sensitivity was 0.4205 μA/μM. The determination of EP was successfully and satisfactorily carried out in real samples such as human blood serum and urine at the poly(DPSA) sensor. To the best knowledge of this work, this is the first study that detect the EP in the presence of ascorbic acid at poly(DPSA) sensor in the literature.

Determination of Drimarene Blue X-BLN at a glassy carbon electrode by differential pulse voltammetry

2011 ◽  
Vol 76 (12) ◽  
pp. 1765-1773 ◽  
Author(s):  
Abd-Elgawad M. Radi ◽  
Mohammed R. Mostafa ◽  
Reda M. Elshafey ◽  
Talaat A. Hegazy
Keyword(s):  
Differential Pulse Voltammetry ◽  
Glassy Carbon Electrode ◽  
Glassy Carbon ◽  
Supporting Electrolyte ◽  
Differential Pulse ◽  
Redox Couple ◽  
Carbon Electrode ◽  
Validation Parameters ◽  
Pulse Voltammetry

The electrochemical oxidation behaviour of Drimarene Blue X-BLN (DB) has been investigated in phosphate buffers (pH 2.54–10.18) by cyclic and differential pulse voltammetry (DPV) at a glassy carbon electrode (GCE). The oxidation of DB dye generated well-defined pH-dependent two pairs of quasi-reversible anodic-cathodic peak couples. DB exhibited the second redox couple over the entire pH range, while the first redox couple disappeared for pH ≥ 6.70. The redox processes were adsorption-controlled. An electroanalytical method was developed for the determination of DB in phosphate buffer solution (pH 2.85) as supporting electrolyte using DPV. The anodic current heights varied linearly with DB concentrations in the ranges 2 × 10–6–3 × 10–5 and 6 × 10–6–3 × 10–5 mol l–1 with limits of detection (LOD) of 8.7 × 10–7 and 5.7 × 10–7 mol l–1 and limits of quantification (LOQ) of 2.9 × 10–6 and 1.9 × 10–6 mol l–1 for the first and second anodic peaks, respectively. Validation parameters, such as accuracy, precision and recovery were evaluated. The proposed method was successfully applied to the determination of DB in tap water and the analytical results compared well with those obtained by the spectrophotometric method.

scholarly journals Electrochemical Analysis of Antichemotherapeutic Drug Zanosar in Pharmaceutical and Biological Samples by Differential Pulse Polarography

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Chennupalle Nageswara Reddy ◽  
Puthalapattu ReddyPrasad ◽  
NeelamYughandhar Sreedhar
Keyword(s):  
Human Urine ◽  
Supporting Electrolyte ◽  
Differential Pulse ◽  
Pharmaceutical Formulation ◽  
Urine Samples ◽  
Differential Pulse Polarography ◽  
Human Urine Samples ◽  
Pulse Polarography ◽  
Spiked Human Urine

The electrochemical reduction of zanosar was investigated systematically by direct current polarography, cyclic voltammetry, and differential pulse polarography (DPP). A simple DPP technique was proposed for the direct quantitative determination of anticancer drug zanosar in pharmaceutical formulation and spiked human urine samples for the first time. The reduction potential was −0.28 V versus Ag/AgCl with a hanging mercury drop electrode in Britton-Robinson buffer as supporting electrolyte. The dependence of the intensities of currents and potentials on pH, concentration, scan rate, deposition time, and nature of the supporting electrolyte was investigated. The calibration curve was found to be linear with the following equation:y=0.4041x+0.012, with a correlation coefficient of 0.992 (R2) over a concentration range from1.0×10-7 M to1.0×10-3 M. In the present investigation, the achieved limit of detection (LOD) and limit of quantization (LQD) were7.42×10-8 M and2.47×10-8 M; respectively. Excipients did not interfere with the determination of zanosar in pharmaceutical formulation and spiked urine samples. Precision and accuracy of the developed method were checked by recovery studies in pharmaceutical formulation and spiked human urine samples.

scholarly journals SENSITIVE MULTIRESIDUE QUANTIFICATION OF PROCYMIDONE AND TEBUTHIURON ON CARBON PASTE ELECTRODE BY DIFFERENTIAL-PULSE VOLTAMMETRY

2016 ◽  
Vol 2 (3) ◽  
pp. 171-189
Author(s):  
Meilene Ribeiro Fidélis ◽  
Leonardo Luiz Okumura ◽  
Ástrea Filomena de Souza Silva ◽  
Alexandre Gurgel ◽  
Adelir Aparecida Saczk
Keyword(s):  
Differential Pulse Voltammetry ◽  
Carbon Paste Electrode ◽  
Supporting Electrolyte ◽  
Differential Pulse ◽  
Carbon Paste ◽  
Intermediate Precision ◽  
Water Matrix ◽  
Quantitative Analyses ◽  
Pulse Voltammetry ◽  
Paste Electrode

  Qualitative electrochemical characterization of procymidone (PRO) and tebuthiuron (TBH) was carried out by cyclic voltammetry using a carbon paste electrode. The studies suggest that analyte mass transfer is controlled by diffusion, and that oxidation of PRO and TBH occurs by means of irreversible electronic transfer of one electron. Oxidation of PRO and TBH occurs close to +0.820 V and +1.075 V (vs. Ag|AgCl, KCl 3.0 mol L-1), respectively, in a 0.1-M KOH solution as supporting electrolyte. Quantitative analyses were carried out by differential-pulse voltammetry, a technique which is more sensitive and selective. Detection and quantification limits were determined for PRO and TBH in the absence of matrix, in a potable-water matrix, and in a nonpotable-water matrix, for which the ranges of reproducibility, intermediate precision and recovery rates were (1.01 and 4.20 %), (4.08 and 9.56 %), and (90.6 and 115 %) for PRO, and (1.59 and 3.92 %), (4.84 and 7.46 %), and (91.3 and 119 %), for TBH, respectively. The results indicate that the new method is selective, simple and cheap to simultaneously quantify PRO and TBH in water samples.

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