Determination of Glucose with Cellulose Acetate/Glucose Oxidase Modified Carbon Paste Electrodes

An amperometric biosensor for glucose determination was developed using a carbon paste electrode (CPE) modified with cellulose acetate (CA)/glucose oxidase (GOx) bilayer membrane through the electrostatic interaction between them. The CA membrane was used as matrix for enzyme immobilization via microencapsulation technique, is enzyme placed between two membranes. CA/GOx membrane was attached to CPE surface containing ferrocene (Fc). By using proposed amperometric biosensor, glucose concentration was determined as well as its characteristic. The modified Fc–graphite electrode with CA/GOx bilayer membrane for glucose had optimum measurement conditions at work emf of 874 mV, CA concentration of 10% and amount Fc of 0.021 mg. The biosensor showed good performance at glucose concentration range of 0.05–3 mM and limit of detection was 0.024 mM. Proposed biosensor has good reproducibility with relative standard deviation (RSD) was less than 5% up to 7 times use (in the defined condition 4 ˚C). Glucose measurement result in human serum of diabetes mellitus patients showed conformity with result of reference method, MediSense Optium glucose test kit.

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A Facile In-Situ Development of L-Valine Film onto the Surface of Carbon Paste Electrode Towards the Detection of Environmentally Hazardous 4-Amino Phenol

Zeitschrift für Physikalische Chemie ◽

10.1515/zpch-2019-0007 ◽

2019 ◽

Vol 0 (0) ◽

Author(s):

T. Venu Gopal ◽

Tukiakula Madhusudana Reddy ◽

P. Shaikshavali ◽

G. Venkataprasad ◽

P. Gopal

Keyword(s):

Cyclic Voltammetry ◽

Carbon Paste Electrode ◽

Electrochemical Impedance ◽

Limit Of Detection ◽

Small Scale ◽

Carbon Paste ◽

Relative Standard ◽

Paste Electrode

Abstract A small scale of environmentally hazardous 4-aminophenol can show significant impact on human health. Hence, in the present work, we have designed L-Valine film (Vf) modified carbon paste electrode (Vf/CPE) for the determination of 4-aminophenol. Herein, a facile in-situ L-Valine film was developed by electrochemical polymerization method onto the surface of bare carbon paste electrode (BCPE) with the help of cyclic voltammetry (CV) technique. A two-folds of electrochemical peak current enhancement was achieved at Vf/CPE in comparison with BCPE towards the determination of 4-aminophenol in optimum pH 7.0 of phosphate buffer solution (PBS). This was achieved due to the large surface area and conductive nature of Vf/CPE, which was concluded through the techniques of cyclic voltammetry and electrochemical impedance spectroscopy (EIS). The effect of pH of buffer and scan rate studies were successfully studied. Morphological changes of BCPE and Vf/CPE was studied with the help of scanning electron microscopy (SEM). The formation of Vf on CPE was also analyzed by Fourier transform infrared (FTIR) spectra. Under the optimized conditions, the limit of detection (LOD) and limit of quantification (LOQ) values of 4-aminophenol were estimated with the aid of chronoamperometry (CA) technique and was found to be 9.8 μM and 32 μM, respectively. Finally the proposed method was found to have satisfactory repeatability, reproducibility and stability results with low relative standard deviation (RSD) values.

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Electroanalysis Of Paracetamol By A Carbon Paste Electrode Modified By Zinc: Analytical Application In Human Blood

METHODS AND OBJECTS OF CHEMICAL ANALYSIS ◽

10.17721/moca.2021.25-31 ◽

2021 ◽

Vol 16 (1) ◽

pp. 25-31

Author(s):

Hayat EL Ouafy ◽

Tarik EL Ouafy ◽

Mustapha Oubenali ◽

Mohamed Mbarki ◽

Malika Echajia ◽

...

Keyword(s):

Human Blood ◽

Carbon Paste Electrode ◽

Catalytic Effect ◽

Limit Of Detection ◽

Detection Sensitivity ◽

Modified Carbon Paste Electrode ◽

Potential Range ◽

Carbon Paste ◽

Relative Standard ◽

Paste Electrode

The present work describes the catalytic effect of zinc particles for electroanalysis the paracetamol (PAR). The working electrode was prepared by mixing the zinc with the carbon powder. The voltammetric behavior of paracetamol was studied when an anodic peak to appear at 0.35 V in 0.1 M Na2SO4 solution (pH 12). The peak resulting from the irreversible oxidation of paracetamol on the zinc modified carbon paste electrode (Zn/CPE). The catalytic effect was evaluated by cyclic voltammetry (CV) and square wave voltammetry (SWV). The electrocatalytic behavior of the zinc particles is allotted to its chemical and physical properties. This electrode has a good performance for the electroanalysis of paracetamol. To obtain an electrochemical analysis of paracetamol oxidation at the surface of Zn/CPE, the voltammograms are used in a potential range of - 1.5 V to 1.5 V. More, Zn/CPE can be utilized successfully to ameliorate the electroanalysis of paracetamol at very feeble concentration and with high detection sensitivity. The limit of detection (LD) and quantification (LQ) obtained are respectively 7.52·10-8 mol L-1 and 2.6·10-7 mol L-1. Then the relative standard deviation (RSD) at 2.0·10-5 mol L-1 PAR concentration was 2.88 % for nine repetitions. Afterward, the presented method was used to electroanalysis paracetamol in human blood samples with satisfying results.

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Voltammetric study of secnidazole and its determination in pharmaceutical tablet using 1, 4-benzoquinone modified carbon paste electrode

10.31221/osf.io/72azx ◽

2019 ◽

Author(s):

Chem Int

Keyword(s):

Carbon Paste Electrode ◽

Limit Of Detection ◽

Modified Carbon Paste Electrode ◽

Carbon Paste ◽

Buffer Solution ◽

Limit Of Quantification ◽

Pharmaceutical Tablet ◽

Relative Standard ◽

Paste Electrode

In this study voltammetric behaviour of secnidazole (SCZ) at 1, 4-Benzoquinone Modified Carbon Paste Electrode (1,4-BQMCPE) was investigated in Britton Robinson buffer solution using cyclic voltammetric technique. A well-defined cathodic peak was observed for the SCZ in the entire pH range. The current increases steadily with scan rate and the results indicated that the process is irreversible reduction and adsorption controlled. The number of electrons transferred and different kinetic parameters like transfer coefficient and rate constant were calculated by using cyclic voltammetry technique. Differential pulse voltammetric method has been used for the determination of SCZ content in pharmaceutical tablet. This method enabled to determine SCZ in the concentration range 1.0 × 10-8 to 4.0 × 10-4 M. The limit of detection (LOD) and limit of quantification (LOQ) were found to be 2.13 × 10-9 and 2.85 × 10-9 respectively. The method was applied to determine the content of SCZ in different sample solutions of SCZ tablet with excellent recovery and relative standard deviation results (99.892±1.53 respectively) for spiked standard SCZ in tablet sample solutions. The selectivity of the method for SCZ was further studied in the presence of selected potential interferents such as fluconazole, azithromycin etc and confirmed the potential applicability of the developed method for the determination of SCZ in real pharmaceutical tablets.

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Direct Spectrophotometric Determination of Glimepiride in Pure Form And Pharmaceutical Formulations Using Bromocresol Purple

JOURNAL OF ADVANCES IN CHEMISTRY ◽

10.24297/jac.v15i2.7454 ◽

2018 ◽

Vol 15 (2) ◽

pp. 6186-6198

Author(s):

Abdul Aziz Ramadan ◽

Souad Zeino

Keyword(s):

Limit Of Detection ◽

Reference Method ◽

Pharmaceutical Formulations ◽

Molar Absorptivity ◽

Bromocresol Purple ◽

Reaction Conditions ◽

Reagent Blank ◽

Limit Of Quantification ◽

Relative Standard

A simple, direct and accurate spectrophotometric method has been developed for the determination of Glimepiride (GLM) in pure and pharmaceutical formulations by complex formation with bromocresol purple (BCP). The method involves the formation of a yellow ion-pair complex between BCP with glimepiride at pH<3,8; after reacting GLM with Na2CO3 to give C24H33N4H+O5NaS which is extracted by chloroform. The formed complex [GLM]:[ BCP] was measured at lmax 418 nm against the reagent blank prepared in the same manner. Variables were studied in order to optimize the reaction conditions. Molar absorptivity (e) for complex was 20600 L.mol-1.cm-1. Beerâ€™s law was obeyed in the concentration range of 1.226 â€“ 46.608 mg.mL-1 in present of 5.0x10-4 mol/l of BCP with good correlation coefficient (R2= 0.9997). The relative standard deviation did not exceed 3.6%. The limit of detection (LOD) and the limit of quantification (LOQ) were 0.15 and 0.46 mg.mL-1, respectively. The proposed method was validated for specificity, linearity, precision and accuracy, repeatability, sensitivity (LOD and LOQ) and robustness. The developed method is applicable for the determination of GLM in pure and different dosage forms with average assay of 98.8 to 102.0% and the results are in good agreement with those obtained by the RP-HPLC reference method.

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Detection of Brevetoxin in Human Plasma by ELISA

Journal of Analytical Toxicology ◽

10.1093/jat/bkab010 ◽

2021 ◽

Author(s):

Brady R Cunningham ◽

Rebecca M Coleman ◽

Adam M Schaefer ◽

Elizabeth I Hamelin ◽

Rudolph C Johnson

Keyword(s):

Human Plasma ◽

Limit Of Detection ◽

Cross Reactivity ◽

Quantitative Detection ◽

Red Tides ◽

Plasma Samples ◽

Detection Range ◽

Paralytic Shellfish ◽

Test Kit ◽

Relative Standard

Abstract Florida red tides have become more common and persistent in and around the Gulf of Mexico. When in bloom, red tides can produce brevetoxins in high concentrations, leading to human exposures primarily through contaminated food and ocean spray. The research described here includes adapting and validating a commercial brevetoxin water test kit for human plasma testing. Pooled plasma was fortified with a model brevetoxin, brevetoxin 3, at concentrations from 0.00500 to 3.00 ng/mL to generate calibration curves and quality control samples. The quantitative detection range was determined to be 0.0400–2.00 ng/mL brevetoxin 3 equivalents with inter- and intraday accuracies ranging from 94.0% to 109% and relative standard deviations <20%, which is within the US Food and Drug Administration guidelines for receptor-binding assays. Additionally, cross-reactivity was tested using 4 of the 10 known brevetoxins and 12 paralytic shellfish toxins. The cross-reactivity varied from 0.173% to 144% for the commercially available brevetoxin standards and 0% for the commercially available paralytic shellfish toxin standards. Fifty individual unexposed human plasma samples were measured to determine the limit of detection and endogenous interferences to the test. The validated method was used to test 31 plasma samples collected from humans potentially exposed to brevetoxins, detecting 11 positives. This method has been proven useful to measure human exposure to brevetoxins and can be applied to future exposure events.

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DEVELOPMENT AND VALIDATION OF DIFFERENTIAL PULSE POLAROGRAPHIC ANALYSIS OF FENOFIBRATE IN PURE AND PHARMACEUTICAL DOSAGE FORMS USING DROPPING MERCURY ELECTRODE

International Journal of Pharmacy and Pharmaceutical Sciences ◽

10.22159/ijpps.2016v8i10.12762 ◽

2016 ◽

Vol 8 (10) ◽

pp. 284

Author(s):

Abdul Aziz Ramadan ◽

Hasna Mandil ◽

Reham Abu-saleh

Keyword(s):

Limit Of Detection ◽

Mercury Electrode ◽

Reference Method ◽

Differential Pulse ◽

Dosage Forms ◽

Pharmaceutical Dosage Forms ◽

Polarographic Analysis ◽

Relative Standard ◽

Dropping Mercury Electrode

Objective: An easy, fast, accurate and sensitive differential pulse polarographic analysis for determination of fenofibrate (FEN) in pure and pharmaceutical dosage forms using dropping mercury electrode (DME) was applied.Methods: The method involves the electrochemical reduction of fenofibrate at DME by differential pulse polarographic analysis (DPPA). Different buffer solutions were used over a wide pH range (1.0–10.0). The best definition of the analytical signals was found in lithium perchlorate trihydrate buffer at pH 6.0 containing 24% (v/v) acetonitrile at-994 to-1025mV (versus Ag/AgCl).Results: Under optimized conditions the peak current (Ip) is linear over the range 0.0361-3.608 μg/ml. The DPPA was used successfully for the determination of FEN in pure and pharmaceutical dosage forms. The relative standard deviation did not exceed 2.1% for the concentration of FEN 0.0361 μg/ml. Regression analysis showed a good correlation coefficient (R2= 0.9994) between Ip and concentration at the mentioned range. The limit of detection (LOD) and the limit of quantification (LOQ) was to be 0.0025 and 0.0076 μg/ml, respectively. The proposed method was validated for linearity, precision and accuracy, repeatability, sensitivity (LOD and LOQ), robustness and specificity with an average recovery of 99.8-100.6%.Conclusion: The developed method is applicable for the determination of FEN in pure and different dosage forms with the assay of marketed formulations 99.8-104.0% and the results are in good agreement with those obtained by square-wave voltammetry (SWV) reference method.Keywords: Differential pulse polarographic analysis, Fenofibrate, Pharmaceutical formulations

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MICELLAR ENHANCED SYNCHRONOUS FLUORESCENCE FOR THE ASSAY OF SUMATRIPTAN SUCCINATE IN PHARMACEUTICAL TABLETS

International Journal of Applied Pharmaceutics ◽

10.22159/ijap.2019v11i2.31118 ◽

2019 ◽

pp. 218-223

Author(s):

SAFWAN M. FRAIHAT

Keyword(s):

Limit Of Detection ◽

Fluorescence Emission ◽

Reference Method ◽

Synchronous Fluorescence ◽

Pharmaceutical Tablets ◽

Sumatriptan Succinate ◽

Accuracy And Precision ◽

Relative Standard ◽

Wide Range

Objective: To develop a sensitive, fast and selective method for the determination of sumatriptan succinate (SUM) in pharmaceutical samples. Methods: The method is based on measuring the synchronous fluorescence of SUM using ∆λ of (120 nm) and at a wavelength of excitation and emission of 230 and 325 nm respectively, using Agilent Technology, Cary eclipse, G9800AA model Luminescence spectrometer. Effect of variables on fluorescence emission intensities was studied such as solvent, surfactant, and pH. The proposed method was validated in term of linearity, limit of detection as per the international conference on harmonization guidelines ICH Q2 (R1). Results: The linearity of the method was obtained with a wide range of (50-150) ng/ml with a high value of correlation coefficient value of (0.992). Limits of detection (LOD) and limits of quantitation (LOQ) were found to be 16.3 and 49.5 ng/ml respectively, the mean recovery was found to be 99.1% with low relative standard deviation (% RSD). The method was also compared statistically with the reference method using t-test and f-test, the results show no difference either in pure or pharmaceutical tablets. Conclusion: The obtained results revealed that the developed method can be applied successfully for the determination of SUM in drug formulations samples with good accuracy and precision.

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FIRST-ORDER ULTRAVIOLET DERIVATIVE SPECTROPHOTOMETRIC METHODS FOR DETERMINATION OF RESERPINE IN ANTIHYPERTENSION TABLET

Indonesian Journal of Chemistry ◽

10.22146/ijc.21341 ◽

2012 ◽

Vol 12 (3) ◽

pp. 268-272 ◽

Cited By ~ 1

Author(s):

Latifah K Darusman ◽

Mohamad Rafi ◽

Wulan Tri Wahyuni ◽

Rizna Azrianiningsari

Keyword(s):

Limit Of Detection ◽

Low Cost ◽

Reference Method ◽

Ml Estimation ◽

Mean Values ◽

First Order ◽

Spectrophotometric Methods ◽

Relative Standard ◽

Limit Of Quantitation

A new ultraviolet derivative spectrophotometry (UVDS) method has been developed for determination of reserpine in antihypertension tablets. A first-order UVDS based on the measurement of the distance between peaks to baseline (DZ) at the wavelength of 312 nm was used. Evaluation of analytical performance showed that accuracy as percentage recovery was 99.18-101.13%, precision expressed as relative standard deviation (RSD) was 1.91% and linear correlation was also obtained 0.9998 in the range of 10-50 µg/mL. Estimation of limit of detection and limit of quantitation was 0.8868 µg/mL and 2.6874 µg/mL, respectively. As a reference method, HPLC methods from United States Pharmacopiea (USP) were used. Commercially tablets available were analyzed by the two methods. The content of reserpine in tablets was found 0.2260±0.0033 mg by UVDS and 0.2301±0.0051 mg by the USP methods. The result obtained from the two methods was compared statistically using F-test and t-test and showed no significant differences between the variance and mean values of the two methods at 95% confidence level. This method was faster, easier, low cost and gave result as well as the reference method published by USP.

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DNA as a Support for Glucose Oxidase Immobilization at Prussian Blue-Modified Glassy Carbon Electrode in Biosensor Preparation

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2006.17977 ◽

2006 ◽

Vol 6 (11) ◽

pp. 3539-3542

Author(s):

A. K. M. Kafi ◽

Dong-Yun Lee ◽

Sang-Hyun Park ◽

Young-Soo Kwon

Keyword(s):

Prussian Blue ◽

Glucose Oxidase ◽

Glassy Carbon ◽

Glucose Concentration ◽

High Sensitivity ◽

Glucose Biosensor ◽

Experimental Conditions ◽

Sensor Performance ◽

Relative Standard ◽

Sensitivity And Selectivity

An amperometric glucose biosensor has been developed using DNA as a matrix of Glucose oxidase (GOx) at Prussian-blue (PB)-modified glassy carbon (GC) electrode. GC electrode was chemically modified by the PB. GOx was immobilized together with DNA at the working area of the PB-modified electrode by placing a drop of the mixture of DNA and GOx. The response of the biosensor for glucose was evaluated amperometrically. Upon immobilization of glucose oxidase with DNA, the biosensor showed rapid response toward the glucose. On the other hand, no significant response was obtained in the absence of DNA. Experimental conditions influencing the biosensor performance were optimized and assessed. This biosensor offered an excellent electrochemical response for glucose concentration in μ mol level with high sensitivity and selectivity and short response time. The levels of the relative standard deviation (RSDs), (<4%) for the entire analyses reflected a highly reproducible sensor performance. Through the use of optimized conditions, a linear relationship between current and glucose concentration was obtained up to 4 × 10−4 M. In addition, this biosensor showed high reproducibility and stability.

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Ion Chromatographic Method for the Simultaneous Determination of Anions and Cations in Firecrackers and Matches Samples as Known Potential Explosives

ALCHEMY Jurnal Penelitian Kimia ◽

10.20961/alchemy.15.1.27570.138-148 ◽

2019 ◽

Vol 15 (1) ◽

pp. 138

Author(s):

Muhammad Amin ◽

Lee Wah Lim

Keyword(s):

Cation Exchange ◽

Anion Exchange ◽

Mobile Phase ◽

Limit Of Detection ◽

Reference Method ◽

Anion Exchange Column ◽

Exchange Column ◽

Relative Standard ◽

Cation Exchange Column

A reference ion chromatography method based on column switching has been presented for the simultaneous determining anions (Cl−, ClO3−, NO2−, SO42−, and NO3−) and/or cations (NH4+, Na+, K+, Ca2+, and Mg2+) using one pump, one type of mobile phase, and one detector. The reference method performed anion-exchange column and cation-exchange column and arranged serially via one 10-port valve. The determination of either anions or cations in one determination system could be made by switching the valve. When the use of 1.25 mM trimellitic acid as a mobile phase and the instrument was operated at a flow rate of 0.6 mL/min, five anions and five cations were determined on the anion-exchange column and the cation-exchange column, respectively. All anions target could be determined completely within 55 minutes, whereas the cations target could be determined within 35 minutes. The calculation of limit of detection using S/N=3 was 3.85 − 14.10 µM for anions and 2.95 − 10.58 µM for cations. The relative standard deviations of all ions were less than 3.82%, 3.29%, and 3.21% for retention time, peak area, and peak height, respectively. The reference method was then applied for the simultaneous determining anions and/or cations contained in firecrackers and matches samples as known potentially explosives.

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