共查询到5条相似文献,搜索用时 0 毫秒
1.
Francisco Wirley P. Ribeiro Amanda S. Cardoso Rafael R. Portela Janete E. S. Lima Sergio A. S. Machado Pedro de Lima‐Neto Djenaine De Souza Adriana N. Correia 《Electroanalysis》2008,20(18):2031-2039
The electrochemical oxidation of promethazine hydrochloride was made on highly boron‐doped diamond electrodes. Cyclic voltammetry experiments showed that the oxidation mechanisms involved the formation of an adsorbed product that is more readily oxidized, producing a new peak with lower potential values whose intensity can be increased by applying the accumulation potential for given times. The parameters were optimized and the highest current intensities were obtained by applying +0.78 V for 30 seconds. The square‐wave adsorptive voltammetry results obtained in BR buffer showed two well‐defined peaks, dependent on the pH and on the voltammetric parameters. The best responses were obtained at pH 4.0, frequency of 50 s?1, step of 2 mV, and amplitude of 50 mV. Under these conditions, linear responses were obtained for concentrations from 5.96×10?7 to 4.76×10?6 mol L?1, and calculated detection limits of 2.66×10?8 mol L?1 (8.51 μg L?1) for peak 1 and of 4.61×10?8 mol L?1 (14.77 μg L?1) for peak 2. The precision and accuracy were evaluated by repeatability and reproducibility experiments, which yielded values of less than 5.00% for both voltammetric peaks. The applicability of this procedure was tested on commercial formulations of promethazine hydrochloride by observing the stability, specificity, recovery and precision of the procedure in complex samples. All results obtained were compared to recommended procedure by British Pharmacopeia. The voltammetric results indicate that the proposed procedure is stable and sensitive, with good reproducibility even when the accumulation steps involve short times. It is therefore very suitable for the development of the electroanalytical procedure, providing adequate sensitivity and a reliable method. 相似文献
2.
Luisa Célia Melo Djenaine De Souza Pedro de Lima‐Neto Adriana Nunes Correia 《Electroanalysis》2010,22(21):2502-2510
The highly boron‐doped diamond electrode (HBDD) combined with square wave voltammetry (SWV) was used in the development of an analytical procedure for diquat determination in potato and sugar cane samples and lemon, orange, tangerine and pineapple juices. Preliminary experiments realised in a medium of 0.05 mol L?1 Na2B4O7 showed the presence of two voltammetric peaks around ?0.6 V and around ?1.0 V vs. Ag/AgCl/Cl? 3.0 mol L?1, where the first peak could be successfully used for analytical proposes due the facility in the electrode surface renovation. After the experimental and voltammetric optimisation, the calculated detection and quantification limits were 1.6×10?10 mol L?1 and 5.3×10?10 mol L?1 (0.057 µg L?1 and 0.192 µg L?1, respectively), which are lower than the maximum residue limit established for fresh food samples by the Brazilian Sanitary Vigilance Agency. The proposed methodology was used to determine diquat residues in potato and sugar cane samples and lemon, orange, tangerine and pineapple juices and the calculated recovery efficiencies indicated that the proposed procedure presents higher robustness, stability and sensitivity, good reproducibility, and is very adequate for diquat determination in complex samples. 相似文献
3.
Eric Oliveira Faria Antônio Carlos Viera Lopes Junior Dênio Emanuel Pires Souto Fernando Roberto Figueiredo Leite Flávio Santos Damos Rita de Cássia Silva Luz Alexandre Soares dos Santos Diego Leoni Franco Wallans Torres Pio dos Santos 《Electroanalysis》2012,24(5):1141-1146
This work presents a simple, fast and low‐cost method for simultaneous determination of acetylsalicylic acid (ASA), without alkaline hydrolysis and caffeine (CF) in pharmaceutical formulations using a boron‐doped diamond as the working electrode through differential pulse voltammetry. A good repeatability was reached for 20 measurements, with a low relative standard deviation of less than 1.0 %. The calibration curves presented a great linear correlation coefficient for both drugs (R=0.999) with a limit of detection of 1.6×10?7 mol L?1 for CF and 2.3×10?7 mol L?1 for ASA. The system was validated in comparison with the official method. 相似文献
4.
Bruna Cláudia Lourenção Roberta Antigo Medeiros Romeu C. Rocha‐Filho Orlando Fatibello‐Filho 《Electroanalysis》2010,22(15):1717-1723
A cathodically pretreated boron‐doped diamond electrode was used for the simultaneous anodic determination of ascorbic acid (AA) and caffeine (CAF) by differential pulse voltammetry. Linear calibration curves (r=0.999) were obtained from 1.9×10?5 to 2.1×10?4 mol L?1 for AA and from 9.7×10?6 to 1.1×10?4 mol L?1 for CAF, with detection limits of 19 μmol L?1 and 7.0 μmol L?1, respectively. This method was successfully applied for the determination of AA and CAF in pharmaceutical formulations, with results equal to those obtained using a HPLC reference method. 相似文献
5.
Ana Paula Pires Eisele Débora Nóbile Clausen César Ricardo Teixeira Tarley Luiz Henrique Dall'Antonia Elen Romão Sartori 《Electroanalysis》2013,25(7):1734-1741
An electroanalytical method for the simultaneous determination of paracetamol (PAR), caffeine (CAF), and orphenadrine (ORPH) using the square‐wave voltammetry (SWV) and a cathodically pretreated boron‐doped diamond electrode was developed. The method exhibits linear responses to PAR, CAF, and ORPH in the concentration ranges 5.4×10?7–6.1×10?5 M, 7.8×10?7–3.5×10?5 M, and 7.8×10?7–3.5×10?5 M, respectively, with detection limits of 2.3×10?7 M, 9.6×10?8 M, and 8.4×10?8 M, respectively. The proposed method was successfully applied in the simultaneous determination of these analytes in pharmaceutical formulations. 相似文献