Voltammetric and amperometric determination of N-nitroso antineoplastic drugs at mercury and amalgam electrodes

2009 ◽  
Vol 74 (11-12) ◽  
pp. 1697-1713 ◽  
Author(s):  
Karolina Pecková ◽  
Lucie Vrzalová ◽  
Vladimír Bencko ◽  
Jiří Barek
Keyword(s):  
Mercury Electrode ◽  
Amperometric Detection ◽  
Current Response ◽  
Antineoplastic Drugs ◽  
Amperometric Determination ◽  
Silver Solid Amalgam Electrode ◽  
Amalgam Electrode ◽  
Relative Standard ◽  
Limit Of Quantitation

A hanging mercury drop electrode and a mercury meniscus modified silver solid amalgam electrode were used as electroanalytical sensors for voltammetric determination of antineoplastic drugs carmustine, lomustine and streptozotocin containing reducible N-nitroso groups. On the example of carmustine it was shown that its one-step reduction proceeds at substantially more negative potentials at amalgam electrode as compared with mercury electrode. Both electrodes offer satisfactory repeatability of current response (relative standard deviations < 5%) using DC voltammetry and differential pulse voltammetry. The achieved limits of determination lie mostly in the 10–7 mol l–1 concentration range. The mentioned voltammetric methods were applied to determination of carmustine and lomustine in pharmaceutical formulations. Further, the mercury meniscus modified silver solid amalgam electrode was employed in a “wall-jet” amperometric detection cell in the determination of carmustine by flow injection analysis. Under optimized conditions (run electrolyte Britton– Robinson buffer of pH 7.0; flow rate 5.5 ml min–1; detection potential –1.5 V; injection volume 0.02 ml) the limit of quantitation 7.1 × 10–6 mol l–1 was achieved.

The use of silver solid amalgam electrode for voltammetric and amperometric determination of nitroquinolines

2009 ◽  
Vol 54 (7) ◽  
pp. 1939-1947 ◽  
Author(s):  
Ivan Jiranek ◽  
Karolina Peckova ◽  
Zuzana Kralova ◽  
Josino C. Moreira ◽  
Jiri Barek
Keyword(s):  
Amperometric Determination ◽  
Silver Solid Amalgam Electrode ◽  
Amalgam Electrode

Voltammetric determination of Nordiazepam at meniscus modified silver solid amalgam electrode

2014 ◽  
Vol 7 (2) ◽  
pp. 105-108 ◽  
Author(s):  
Petr Samiec ◽  
Zuzana Navrátilová
Keyword(s):  
Ph Value ◽  
Ph Effect ◽  
Differential Pulse ◽  
Current Response ◽  
Limit Of Quantification ◽  
Silver Solid Amalgam Electrode ◽  
Amalgam Electrode ◽  
Optimum Ph ◽  
Pulse Voltammetry

Abstract New electrochemical method for determination of Nordiazepam (NDZ) at meniscus modified silver solid amalgam electrode (m-AgSAE) was developed utilizing differential pulse voltammetry (DPV). The pH effect on the current response of NDZ was studied in the mixture of Britton-Robinson buffer (BR) and methanol (9:1) with optimum pH value of 10. The calibration dependences were examined under the optimal conditions and linearity in the range from 2 × 10−6 to 1 × 10−4 mol L−1 with limit of quantification of 1.7 × 10−6 mol L−1 were accomplished.

Determination of subnanogram amounts of sulfur dioxide and sulfites by pneumatopotentiometry

1986 ◽  
Vol 51 (10) ◽  
pp. 2077-2082 ◽  
Author(s):  
Jan Langmaier ◽  
František Opekar
Keyword(s):  
Sulfur Dioxide ◽  
Redox Potential ◽  
Sodium Hydroxide ◽  
Porous Membrane ◽  
Membrane Electrode ◽  
Iodine Monochloride ◽  
Membrane Pores ◽  
Relative Standard ◽  
Limit Of Quantitation

Gold porous membrane electrode has been used for the potentiometric determination of small amounts of sulfur dioxide absorbed in the solutions of sodium tetrachloromercurate or sodium hydroxide. Sulfur dioxide is released by the reaction with an acid into a stream of nitrogen and led to the electrode immersed into the solution of iodine monochloride. Part of SO2 penetrates through the membrane pores into the solution where it is oxidized. The electrode redox potential change is a measure of the SO2 concentration in the absorption solution. In the solution of 1 . 10-5 M[ICl2]- in 0.02 M-HClO4 the limit of quantitation was found to be 0.07 ng SO2 . ml-1. The relative standard deviations of 1.4% and 2.5% were found for the determinations of 10 ng and 0.5 ng of SO2, respectively. Higher concentrations of H2S interfere only in the hydroxide solution. About 10 samples can be analyzed per one hour.

scholarly journals Reverse phase-liquid chromatography assisted protocol for simultaneous determination of lamivudine and tenofovir disoproxil fumarate in combined medication used to control HIV infection: an investigative approach

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Vaibhav S. Adhao ◽  
Suraj R. Chaudhari ◽  
Jaya P. Ambhore ◽  
Sunil Sangolkar ◽  
Raju R. Thenge ◽  
...  
Keyword(s):  
Liquid Chromatography ◽  
Hiv Infection ◽  
Simultaneous Determination ◽  
Tenofovir Disoproxil Fumarate ◽  
Solvent System ◽  
Array Detector ◽  
Technical Requirements ◽  
Relative Standard ◽  
Limit Of Quantitation

Abstract Background Human immunodeficiency virus (HIV) causes severe life-threatening condition, i.e., AIDS. HIV destabilises an individual’s ability to prevent infection. Therefore, the combine medication lamivudine (LVD) and tenofovir disoproxil fumarate (TDF) are prescribed to suppress the amount of HIV infection in individual’s body; thus, the individual’s immune system could function properly. Consequently, the objective of present research work was to investigate robust and sensitive liquid chromatography avenue for simultaneous determination of lamivudine and tenofovir disoproxil fumarate in pure material and combined dosage form. Results The reversed-phase chromatographic separation has been performed through Hypersil BDS C18 column using solvent system composed of 10 mM potassium dihydrogen phosphate (pH 4.0): acetonitrile (60:40% v/v). The determination was executed at 30 oC at 1 mL/min rate for flow of solvent system through column. The eluents of column were monitored at 265 nm using Photodiode Array detector has revealed admirable retention times, i.e., 4.67 and 8.78 min for both drugs, respectively. The calibration curve demonstrated excellent linearity in the range of 10–50 μg/mL for lamivudine and tenofovir disoproxil fumarate with better determination coefficients was more than (r2 0.999). Conclusion The estimable method was effectively validated with respect to accuracy, precision, sensitive (limit of detection and limit of quantitation), robustness, ruggedness, and for selectivity and specificity. The value less than 2 for percentage relative standard deviation for accuracy, precision, robustness, and ruggedness satisfying the acceptance criteria as per procedure of International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use.

Simultaneous Determination of Four Herbicide and Pesticide Residues in Chinese Green Tea Using QuEChERS Purification Procedure and UPLC-MS/MS Analysis

2013 ◽  
Vol 634-638 ◽  
pp. 1586-1590
Author(s):  
Su Fang Wang ◽  
Shou Jie Zhang ◽  
Chun Hong Dong ◽  
Guo Qing Wang ◽  
Jun Feng Guo ◽  
...  
Keyword(s):  
Formic Acid ◽  
Simultaneous Determination ◽  
Green Tea ◽  
Limit Of Detection ◽  
Multiple Reaction Monitoring ◽  
Graphitized Carbon Black ◽  
Ms Analysis ◽  
Relative Standard ◽  
Limit Of Quantitation

A method for simultaneous determination of residuals of four herbicides and pesticides, simazine, carboxin, diflubenzuron and rotenone, in Chinese green tea was developed. In the proposed method, the tea powder was placed in a centrifuge tube with a plug, extracted in saturated aqueous sodium chloride solution and acetonitrile, agitated using vortex oscillator, and then centrifuged 5 min at 4000 rpm. The supernatant solution was purified by primary secondary amine (PSA) sorbent, C18 power, and graphitized carbon black powder, respectively. Then the purified extracts were dissolved with acetonitrile:0.1% formic acid aqueous solution (40:60, V/V) and agitated, filtered using a syringe with 0.22 μm nylon filter prior to UPLC-MS/MS analysis. The UPLC analysis was performed on an ACQUITY UPLC® HSS T3 column (2.1 mm×100 mm, 1.8 µm), using acetonitrile-0.1% formic acid as mobile phase with the flow rate as 0.3 mL•min-1. Injection volume was 10 µL. Positive ionization mode was applied, and the ions were monitored in the multiple reaction monitoring (MRM) mode with curtain gas 0.069 MPa, collision gas 0.052 MPa, ESI ion spray voltage 5000 V, temperature 550 °C, nebulizer gas 0.24 MPa, and turbo gas 0.28 MPa. The limit of detection (LOD) and limit of quantitation (LOQ) of the proposed method are 1 μg•kg-1and 5 μg•kg-1, respectively. The average recoveries of the four pesticides at 10, 20, and 50 µg•kg-1spiking levels range from 77.4% to 95.3%. TheSupersSuperscript textcript textrelative standard deviation (RSD) (n=6) range form 11.83% to 4.52%.

scholarly journals SENSITIVE DETERMINATION OF RELATED SUBSTANCES IN PIOGLITAZONE HYDROCHLORIDE BY HPLC

2017 ◽  
Vol 9 (2) ◽  
pp. 34
Author(s):  
N. Balaji ◽  
Sayeeda Sultana
Keyword(s):  
Mobile Phase ◽  
High Performance ◽  
Limit Of Detection ◽  
High Performance Liquid Chromatographic ◽  
Hplc Method ◽  
Internal Diameter ◽  
Related Substances ◽  
Relative Standard ◽  
Limit Of Quantitation

Objective: An efficient, high performance liquid chromatographic method has been developed and validated for the quantification of related substances in pioglitazone hydrochloride drug substance.Methods: This method includes the determination of three related substances in pioglitazone hydrochloride. The mobile phase A is 0.1% w/v triethylamine in water with pH 2.5 adjusted by dilute phosphoric acid. The mobile phase B is premixed and degassed mixtures of acetonitrile and methanol. The flow rate was 1 ml/min. The elution used was gradient mode. The HPLC column used for the analysis was symmetry C18 with a length of 250 mm, the internal diameter of 4.6 mm and particle size of 5.0 microns.Results: The developed method was found to be linear with the range of 0.006-250% with a coefficient of correlation 0.99. The precision study revealed that the percentage relative standard deviation was within the acceptable limit. The limit of detection and limit of quantitation of the impurities was less than 0.002%and 0.006% with respect to pioglitazone hydrochloride test concentration of 2000 µg/ml respectively. This method has been validated as per ICH guidelines Q2 (R1).Conclusion: A reliable, economical HPLC method was magnificently established for quantitative analysis of related substances of pioglitazone hydrochloride drug substance.

Analysis of Synthetic Antioxidant in Food by Capillary Electrophoresis

2011 ◽  
Vol 361-363 ◽  
pp. 1855-1858 ◽  
Author(s):  
Qian Xiang ◽  
Ying Gao
Keyword(s):  
Capillary Electrophoresis ◽  
Amperometric Detection ◽  
Peak Height ◽  
Butylated Hydroxyanisole ◽  
Applied Potential ◽  
Synthetic Antioxidant ◽  
Separation Potential ◽  
Relative Standard ◽  
Capillary Electrophoretic

A capillary electrophoretic assay for determining synthetic antioxidant butylated hydroxyanisole in food has been developed. The extraction with 70% (v/v) methanol quantitatively extracted synthetic antioxidant. The separation was carried out by CZE using phosphate at a separation potential of 18 kV. Amperometric detection was achieved with an applied potential of 0.60 V. A linear relationship between the peak height and the concentration of the analyte was found in the range 1.8-180 µg/mL for BHA, with correlation coefficient of 0.994. The relative standard deviations of migration time and peak height were 0.19 and 5.3 %, respectively. The method developed was successfully applied for the determination of synthetic antioxidant butylated hydroxyanisole in food. Recovery of butylated hydroxyanisole was 93%.

Voltammetric Determination of Aliphatic Phthalate Esters at a Hanging Mercury Drop Minielectrode and a Meniscus Modified Silver Solid Amalgam Electrode

2010 ◽  
Vol 22 (17-18) ◽  
pp. 1957-1962 ◽  
Author(s):  
Munawar Saeed Qureshi ◽  
Jan Fischer ◽  
Jiří Barek ◽  
Sirajuddin ◽  
Muhammad Iqbal Bhanger
Keyword(s):  
Phthalate Esters ◽  
Voltammetric Determination ◽  
Silver Solid Amalgam Electrode ◽  
Amalgam Electrode

Liquid Chromatographic Determination of Sulfentrazone in Soil

1999 ◽  
Vol 82 (5) ◽  
pp. 1214-1216 ◽  
Author(s):  
G Anthony Ohmes ◽  
Thomas C Mueller
Keyword(s):  
Chromatographic Determination ◽  
Soil Samples ◽  
Ultraviolet Detection ◽  
Liquid Chromatographic Separation ◽  
Relative Standard ◽  
Limit Of Quantitation ◽  
Liquid Chromatographic Determination ◽  
Liquid Chromatographic ◽  
Soluble Components

Abstract A rapid method for the determination of sulfentrazone in soils is described. The method consists of extraction of soil samples with methanol, filtration, liquid chromatographic separation of methanol-soluble components through a C18 column, and ultraviolet detection at 220 nm. Recoveries from fortified surface soils were &gt;85% for sulfentrazone. Average relative standard deviations over the soils examined was 7.7%. A conservative lower limit of quantitation for sulfentrazone was 40 ng/g soil.

scholarly journals Determination of Tianeptine in Tablets by High-Performance Liquid Chromatography with Fluorescence Detection

2007 ◽  
Vol 90 (3) ◽  
pp. 720-724
Author(s):  
Sevgi Tatar Ulu
Keyword(s):  
Lower Limit ◽  
High Performance ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Linear Calibration ◽  
Fluorescence Detector ◽  
Relative Standard ◽  
Validation Parameters ◽  
Limit Of Quantitation

Abstract A sensitive and selective high-performance liquid chromatographic method has been developed for the determination of tianeptine (Tia) in tablets. The method is based on derivatization of Tia with 4-chloro-7-nitrobenzofurazan (NBD-Cl). A mobile phase consisting of acetonitrile10 mM orthophosphoric acid (pH 2.5; 77 + 23) was used at a flow rate of 1 mL/min on a C18 column. The Tia-NBD derivative was monitored using a fluorescence detector, with emission set at 520 nm and excitation at 458 nm. Gabapentin was selected as an internal standard. Linear calibration graphs were obtained in the concentration range of 45300 ng/mL. The lower limit of detection (LOD) was 10 ng/mL at a signal-to-noise ratio of 4. The lower limit of quantitation (LOQ) was 45 ng/mL. The relative standard values for intra- and interday precision were &lt;0.46 and &lt;0.57%, respectively. The recovery of the drug samples ranged between 98.89 and 99.85%. No chromatographic interference from the tablet excipients was found. The proposed method was validated in terms of precision, robustness, recovery, LOD, and LOQ. All the validation parameters were within the acceptance range. The proposed method was applied for the determination of Tia in commercially available tablets. The results were compared with those obtained by an ultraviolet spectrophotometric method using t- and F-tests.

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