scholarly journals Fast and sensitive metronidazole determination by means of voltammetry on renewable amalgam silver based electrode without the preconcentration step

2017 ◽  
Vol 82 (7-8) ◽  
pp. 879-890 ◽  
Author(s):  
Robert Piech ◽  
Joanna Smajdor ◽  
Beata Paczosa-Bator ◽  
Martyna Rumin
Keyword(s):  
Surface Area ◽  
Limit Of Detection ◽  
Pulse Height ◽  
Differential Pulse ◽  
Calibration Graph ◽  
Large Surface Area ◽  
Reduction Peak ◽  
Step Potential ◽  
Relative Standard ◽  
20 Nm

Application of cyclic renewable amalgam silver-based electrode (Hg(Ag)FE) for sensitive metronidazole detection by the differential pulse voltammetry (DPV) is described. The unique properties of the Hg(Ag)FE such as the relative large surface area and its fast and very simple renewal were fully utilized for sensitive measurements. Compared with the classical hanging mercury drop electrode (HMDE), the renewable Hg(Ag)FE significantly increases the reduction peak current of metronidazole because of its large surface area. The effects of various factors for the metronidazole determination such as: pulse height and width, step potential, surface area of the working electrode, and basic electrolyte composition are optimized. The obtained calibration graph is linear from 0.1 (17 ?g L-1) to 2 ?M (342 ?g L-1) with correlation coefficient 0.999. For the Hg(Ag)FE with the surface area of 10.1 mm2 the limit of detection (LOD) is 20 nM (3.4 ?g L-1). The repeatability of the method at a concentration of the analyte of 0.5 ?M (5.6 ?g L?1), expressed as relative standard deviation (RSD) is 2.1 % (n = 7). The proposed method was successfully applied and confirmed by studying recovery of metronidazole from spiked samples.

scholarly journals A New Graphene Quantum Dot Sensor for Estimating an Antibiotic Concentration

MRS Advances ◽  
2018 ◽  
Vol 3 (15-16) ◽  
pp. 825-830
Author(s):  
N.N.N. Ahamed ◽  
W. Fan ◽  
M. Schrlau ◽  
K.S.V. Santhanam
Keyword(s):  
Surface Area ◽  
Saturated Calomel Electrode ◽  
Graphene Quantum Dots ◽  
Differential Pulse ◽  
Large Surface Area ◽  
Reduction Peak ◽  
Ferric Ion ◽  
Sensing Material ◽  
Three Stages ◽  
Electron Reduction

ABSTRACTThe graphene quantum dots (GQD) are unique for several different applications especially in the area of sensors as they provide a platform for large surface area on which sensing material can be attached. We wish to report here a new analytical method for sensing ciprofloxacin (CPFX) antibiotic using GQD electrode in differential pulse voltammetry (DPV) which is based on the ferric ion interaction with CPFX. Ferric ion undergoes a well defined one electron reduction at GQD electrode in DPV at Ep=0.310 V vs saturated calomel electrode (SCE) with a peak width of 0.100 V. When nanomolar to micromolar concentrations of CPFX is present in the electrolytic bath, the ferric ion reduction peak decreases with the appearance of three new peaks at EpI=0.200 V, EpII=0.050 V and EpIII= -0.085V. The three peaks are attributed to the three stages of binding of CPFX with three positive charges of ferric ion. The decrease of the ferric ion peak at 0.31 V is proportional to the concentration of CPFX. Due to large surface area of GQD, the CPFX bound ferric ion shows enhanced currents in comparison to glassy carbon electrode. The sensor is fabricated by depositing GQD containing known concentration of ferric ion. The sensor response to different concentrations of CPFX is measured for an analytical purpose.

scholarly journals Differential Pulse Polarographic Behavior and Quantification of the Flucloxacillin in Pure and Pharmaceutical Dosage Forms Using a Static Mercury Drop Electrode

2018 ◽  
Vol 15 (2) ◽  
pp. 6235-6247
Author(s):  
Abdul Aziz Ramadan ◽  
Hasna Mandil ◽  
Reham Abu Saleh
Keyword(s):  
Limit Of Detection ◽  
Reference Method ◽  
Differential Pulse ◽  
Dosage Forms ◽  
Calibration Graph ◽  
Optimum Conditions ◽  
Limit Of Quantification ◽  
Pharmaceutical Dosage Forms ◽  
Mercury Drop Electrode ◽  
Relative Standard

Differential pulse polarographic analysis (DPPA) by using static mercury drop electrode (SMDE) for quantification of flucloxacillin (FLUX) in pure and pharmaceutical dosage forms was studied. The optimum conditions for the polarographic signal were determined and a study was made of the different parameters affecting the electrochemical process. The best definition of the analytical signals was found in Britton–Robinson buffer (0.06 M) at pH 4.0 . Under the optimum conditions, liner calibration graph, Ip=f(CFLUX) was obtained in the concentration ranges of 0.1 mM (0.0494 ?g.mL-1) to 26 mM (12.8414 ?g.mL-1) at -940 to -1000 mV (versus Ag/AgCl) with relative standard deviations (RSD) did not exceed 2.4% for the concentrations of FLUX (0.0494 ?g.mL-1). Regression analysis showed a good correlation coefficient (R2=9998) between Ip and concentration over the mentioned range. The limit of detection (LOD) and the limit of quantification (LOQ) were to be 0.0040 and 0.0120 ?g.mL-1, respectively. The proposed method was validated for linearity, precision and accuracy, repeatability, sensitivity (LOD and LOQ), robustness and specificity. The developed method is applicable for the determination of FLUX in pure and different dosage forms in presence a same amount of amoxicillin (AMOX) with average recovery of 99.4 to 102.2 % and the results are in good agreement with those obtained by the HPLC reference method.  

Development of a solid-phase extraction – spectrofluorimetric method for trace glutathione determination

2011 ◽  
Vol 89 (4) ◽  
pp. 517-523 ◽  
Author(s):  
Ke-Jing Huang ◽  
Cong-Hui Han ◽  
Ying-Ying Wu ◽  
Chao-Qun Han ◽  
De-Jun Niu ◽  
...  
Keyword(s):  
Solid Phase Extraction ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Signal To Noise Ratio ◽  
Calibration Graph ◽  
Extraction Column ◽  
Phase Extraction ◽  
Selective Reaction ◽  
Spectrofluorimetric Method ◽  
Relative Standard

A simple and efficient solid-phase extraction – spectrofluorimetric method has been developed to determine glutathione (GSH). Fluorescent probe N-(4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-yl)methyl)iodoacetamide (BODIPY Fl-C1-IA) was used as the derivatization reagent. The procedure was based on a BODIPY Fl-C1-IA selective reaction with GSH to form the highly fluorescent product BODIPY Fl-C1-IA–GSH, using a solid-phase extraction column and spectrofluorimetric determination. The variables affecting analytical performance were studied and optimized. The calibration graph using the preconcentration system for GSH was linear over the range of 1–200 nmol/L with a limit of detection of 0.05 nmol/L (signal-to-noise ratio = 3). The relative standard deviation for six replicate determinations of GSH at the 100 nmol/L concentration level was 3.9%. The method was applied to water samples and average recoveries between 87.5% and 111.5% were obtained for spiked samples.

scholarly journals Simultaneous Voltammetric Detection of Acetaminophen and Caffeine Base on Cassava Starch—Fe3O4 Nanoparticles Modified Glassy Carbon Electrode

Chemosensors ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 49 ◽  
Author(s):  
Ani Mulyasuryani ◽  
Rachmat Tjahjanto ◽  
Robi’atul Andawiyah
Keyword(s):  
Fe3o4 Nanoparticles ◽  
Limit Of Detection ◽  
Sodium Tripolyphosphate ◽  
Crosslinking Agent ◽  
Differential Pulse ◽  
Cassava Starch ◽  
Buffer Solution ◽  
Mixture Ratio ◽  
Relative Standard ◽  
Voltammetric Detection

The new molecularly imprinted polymer (MIP) membrane based on cassava starch—Fe3O4—was developed to detect acetaminophen and caffeine simultaneously with the differential pulse voltammetry (DPV) method. Cassava starch was reacted with sodium tripolyphosphate (STPP) as a crosslinking agent, while acetaminophen and caffeine were added as templates. The Fe3O4 nanoparticles in the composite were added to increase the sensor’s sensitivity. The experimental results show that the ratio between cassava starch:STPP:acetaminophen/caffeine in the mixture for MIP membranes influences the sensitivity of the sensor obtained. MIP membranes with the best sensitivity is produced at a mixture ratio of 2:2:1. The sensor performance is also affected by the pH of the solution and the type of buffer solution used. The sensor works very well at pH 2 in PB solution. Sensors produced from GCE modified with MIP membrane from cassava starch—Fe3O4 with acetaminophen and caffeine as templates have linear range concentrations, respectively, at 50–2000 µM and 50–900 µM. Sensor sensitivity was 0.5306 A/M against acetaminophen and 0.4314 A/M against caffeine with Limit of Detection (LoD), respectively, 16 and 23 µM. Sensor selectivity and sensitivity are better than those without MIP and can be applied for the determination of the content of acetaminophen in headache medicine, with an accuracy of 96–99% and with Relative Standard Deviation (RSD) 0.9–2.56%.

scholarly journals Spectrophotometric Determination of Iron(II) after Solid Phase Extraction of Its 2,2′ Bipyridine Complex on Silica Gel-Polyethylene Glycol

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Nahid Pourreza ◽  
Saadat Rastegarzadeh ◽  
Ali Reza Kiasat ◽  
Hossein Yahyavi
Keyword(s):  
Polyethylene Glycol ◽  
Solid Phase Extraction ◽  
Silica Gel ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Extraction Procedure ◽  
Calibration Graph ◽  
Phase Extraction ◽  
Relative Standard

A new solid phase extraction procedure was developed for preconcentration of iron(II) using silica gel-polyethylene glycol (silica-PEG) as an adsorbent. The method is based on retention of iron(II) as 2,2′ bipyridine complex on silica-PEG. The retained complex is eluted by 1.0 mol L−1of sulfuric acid-acetone mixture (1:2) and its absorbance is measured at 518 nm, spectrophotometrically. The effects of different parameters such as pH, concentration of the reagent, eluting reagent, sample volume, amount of adsorbent, and interfering ions were investigated. The calibration graph was linear in the range of 1–60 ng mL−1of iron(II). The limit of detection based on3Sbwas 0.57 ng mL−1and relative standard deviations (R.S.D) for ten replicate measurements of 12 and 42 ng mL−1of iron(II) were 2.4 and 1.7%, respectively. The method was applied to the determination of of iron(II) in water, multivitamin tablet, and spinach samples.

Determination of diltiazem based on the reduction of Cu(II)–BCA complexes in micellar medium

2010 ◽  
Vol 88 (6) ◽  
pp. 533-539 ◽  
Author(s):  
Larissa Zuppardo Lacerda Sabino ◽  
Daniele Cestari Marino ◽  
Horacio Dorigan Moya
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Confidence Level ◽  
Limit Of Detection ◽  
Calibration Graph ◽  
Micellar Medium ◽  
Solution Ph ◽  
Simple Method ◽  
Relative Standard

A simple method was developed for determining microquantities of diltiazem, based on the reduction of copper(II) in buffered solution (pH 7.0) and the use of a micellar medium containing 4,4′-dicarboxy-2,2′-biquinoline acid. The copper(I) produced reacts with 4,4′-dicarboxy-2,2′-biquinoline acid and the complexes formed are spectrophotometrically measured at 558 nm. A typical calibration graph shows good linearity (r = 0.993) from 20 to 100 μg mL–1 of diltiazem. The limit of detection and relative standard deviation were calculated as 12 μg mL–1 (99% confidence level) and 3.5% (40 μg mL–1; n = 6), respectively, with a mean recovery value of 96.5% found in pharmaceutical dosages. A straightforward and effective way to recycle the reagents is addressed. The hazardous aspects of the Cu(I)–BCA reaction are presented as well.

scholarly journals Fast Determination of Auramine O in Food by Adsorptive Stripping Voltammetry

2019 ◽  
Vol 2019 ◽  
pp. 1-6 ◽  
Author(s):  
Thuong Nguyen Thi Kim ◽  
Thi Thu Bui ◽  
Anh Tuan Pham ◽  
Van Thang Duong ◽  
Thi Huong Giang Le
Keyword(s):  
Limit Of Detection ◽  
Electrochemical Behaviour ◽  
Pulse Amplitude ◽  
Reduction Peak ◽  
Hanging Mercury Drop Electrode ◽  
Experimental Conditions ◽  
Mercury Drop Electrode ◽  
Relative Standard ◽  
Limit Of Quantitation ◽  
Auramine O

The electrochemical behaviour of auramine O on the hanging mercury drop electrode has been investigated by cyclic and square wave voltammetry method. Reduction peak of auramine O was irreversible and adsorptive on the hanging mercury drop electrode. The optimal conditions were chosen to be Briton–Robinson buffer pH 9.0, accumulation potential −0.5 V vs. Ag/AgCl/KCl, accumulation time 60 s, pulse amplitude 250 mV·s−1, and frequency 50 Hz. At the optimum experimental conditions, the peak of the target analyte was sharp and asymmetric. The linearity of the peak current depending on the concentration ranged from 4.0 × 10−8 to 6.4 × 10−7 mol L−1. The limit of detection and limit of quantitation were 2.46 × 10−8 mol L−1 and 8.21 × 10−8 mol L−1, respectively. The recovery and relative standard deviation were 94.9% and 2.0% (n = 5). The developed method was successfully applied to determine auramine O in chicken samples with an appropriate sample preparation.

Determination of Ruthenium in Waste Ruthenium-Loaded Carbon Catalyst Samples Using Teflon Pressure Vessel-Assisted Sample Digestion and ICP-OES

2014 ◽  
Vol 1015 ◽  
pp. 570-573
Author(s):  
Xiao Juan Wei ◽  
Jian Ming Pan
Keyword(s):  
Inductively Coupled Plasma ◽  
Limit Of Detection ◽  
Optical Emission ◽  
Calibration Graph ◽  
Emission Spectrometry ◽  
Carbon Catalyst ◽  
Inductively Coupled ◽  
Relative Standard ◽  
Sample Dissolution

A novel method for the determination of ruthenium in waste ruthenium-loaded carbon catalyst samples was established by inductively coupled plasma optical emission spectrometry after samples digested by Teflon pressure digestion vessel with aqua regia. Such experiment conditions were investigated as the influence of sample dissolution methods, digestion time, digestion temperature and interfering ions on the determination. Under the optimized conditions, the limit of detection (LODs) of Ru for tested solution was 9 ng mL-1. The relative standard deviations (RSDs) for Ru was 2.12 % (CRu= 1 mg L-1, n = 7). The linear range of calibration graph for Ru and Zn was 0 ~ 100.00 mg L-1. The proposed method was applied to determine the practical samples with good recoveries and satisfactory results.

scholarly journals Kinetic-Spectrophotometric Determination of Iodide Based on its Inhibitory Effect on the Decolorization Reaction of Methyl Orange

2009 ◽  
Vol 6 (4) ◽  
pp. 1267-1273
Author(s):  
Reyhaneh Rahnama Kozani ◽  
Ferydoun Ashrafi ◽  
Masuod Khalilnezhad ◽  
Mohammad Reza Jamali
Keyword(s):  
Methyl Orange ◽  
Spectrophotometric Determination ◽  
Limit Of Detection ◽  
Inhibitory Effect ◽  
Calibration Graph ◽  
Reaction Products ◽  
Optimum Conditions ◽  
Relative Standard ◽  
Kinetic Spectrophotometric

A simple, sensitive, rapid and reliable method has been developed for spectrophotometric determination of iodide based on its inhibition effect on the redox reaction between bromate and hydrochloric acid. The decolorization of methyl orange by the reaction products was used to monitor the reaction spectrophotometrically at 525 nm. The variables affecting the rate of the reaction were investigated. Under the optimum conditions, the limit of detection is 1.5 × 10-7mol L-1and calibration range is 2.0 × 10-6–1.3 × 10-4mol L-1of iodide. The linearity range of the calibration graph is depends on bromate concentration. The relative standard deviation of ten-replication determination of 8.2 × 10-5mol L-1iodide was 1.4%. The proposed method was applied to the determination of iodide in natural water samples with satisfactory results.

scholarly journals Rapid, Simple, and Sensitive Spectrofluorimetric Method for the Estimation of Ganciclovir in Bulk and Pharmaceutical Formulations

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Garima Balwani ◽  
Emil Joseph ◽  
Satish Reddi ◽  
Vibhu Nagpal ◽  
Ranendra N. Saha
Keyword(s):  
Standard Deviation ◽  
Limit Of Detection ◽  
Pharmaceutical Formulations ◽  
Calibration Graph ◽  
Limit Of Quantification ◽  
Average Percentage ◽  
Ich Guidelines ◽  
Spectrofluorimetric Method ◽  
Relative Standard

A new, simple, rapid, sensitive, accurate, and affordable spectrofluorimetric method was developed and validated for the estimation of ganciclovir in bulk as well as in marketed formulations. The method was based on measuring the native fluorescence of ganciclovir in 0.2 M hydrochloric acid buffer of pH 1.2 at 374 nm after excitation at 257 nm. The calibration graph was found to be rectilinear in the concentration range of 0.25–2.00 μg mL−1. The limit of quantification and limit of detection were found to be 0.029 μg mL−1and 0.010μg mL−1, respectively. The method was fully validated for various parameters according to ICH guidelines. The results demonstrated that the procedure is accurate, precise, and reproducible (relative standard deviation <2%) and can be successfully applied for the determination of ganciclovir in its commercial capsules with average percentage recovery of 101.31 ± 0.90.

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