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Safavi A, Absalan G, Bamdad F. Effect of gold nanoparticle as a novel nanocatalyst on luminol–hydrazine chemiluminescence system and its analytical application. Anal Chim Acta 2008; 610:243-8. [DOI: 10.1016/j.aca.2008.01.053] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2007] [Revised: 01/12/2008] [Accepted: 01/20/2008] [Indexed: 10/22/2022]
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Chamsaz M, Safavi A, Fadaee J. Simultaneous kinetic-spectrophotometric determination of carbidopa, levodopa and methyldopa in the presence of citrate with the aid of multivariate calibration and artificial neural networks. Anal Chim Acta 2007; 603:140-6. [DOI: 10.1016/j.aca.2007.09.006] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2007] [Revised: 08/26/2007] [Accepted: 09/06/2007] [Indexed: 11/28/2022]
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Maleki N, Safavi A, Sedaghati F, Tajabadi F. Efficient electrocatalysis of L-cysteine oxidation at carbon ionic liquid electrode. Anal Biochem 2007; 369:149-53. [PMID: 17716615 DOI: 10.1016/j.ab.2007.04.024] [Citation(s) in RCA: 92] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2007] [Revised: 04/18/2007] [Accepted: 04/20/2007] [Indexed: 10/23/2022]
Abstract
The electrochemistry of L-cysteine (CySH) in neutral aqueous media was investigated using carbon ionic liquid electrode (CILE). Comparative experiments were carried out using glassy carbon electrodes. At CILE, highly reproducible and well-defined cyclic voltammograms were obtained for l-cysteine with a peak potential of 0.49V vs Ag/AgCl, showing that CILE manifests a good electrocatalytic activity toward oxidation of l-cysteine. A linear dynamic range of 2-210microM with an experimental detection limit of 2microM was obtained. The method was successfully applied to the determination of l-cysteine in a sample of soya milk. Cysteine oxidation at CILE does not result in deactivation of the electrode surface. Mechanistic studies showed that, at CILE, the overall CySH oxidation is controlled by the oxidation of the CyS(-) electroactive species.
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Safavi A, Banazadeh AR. Dynamic method as a simple approach for wide range pH measurements using optodes. Anal Chim Acta 2007; 583:326-31. [PMID: 17386563 DOI: 10.1016/j.aca.2006.10.063] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2006] [Revised: 10/22/2006] [Accepted: 10/26/2006] [Indexed: 11/26/2022]
Abstract
In this paper, a flow system equipped with an optode has been suggested for wide range pH measurements. Triacetyl cellulose was used as the optode membrane in which different pH indicators were immobilized. For extending the pH range, the dynamic response rather than the steady-state response of the optode was measured. Since diffusion is the main process governing the system response, different parameters having influence on diffusion of the analyte into the membrane were optimized. Under the optimum conditions, wide range pH determination (up to 11 pH units) is simply achieved regardless of the pKa of the pH indicator immobilized in the membrane. To validate the application of the method different indicators with different structures and pKa values were tested and the results were all confirming the precision and accuracy of the method. The suggested method also has combined advantages of flow systems together with inherent advantages of kinetic systems.
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Maleki N, Absalan G, Safavi A, Farjami E. Ultra trace adsorptive stripping voltammetric determination of atrazine in soil and water using mercury film electrode. Anal Chim Acta 2007; 581:37-41. [DOI: 10.1016/j.aca.2006.08.043] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2006] [Revised: 06/15/2006] [Accepted: 08/08/2006] [Indexed: 10/24/2022]
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Khalilzadeh S, Boloorsaz MR, Safavi A, Farnia P, Velayati AA. Primary and acquired drug resistance in childhood tuberculosis. EASTERN MEDITERRANEAN HEALTH JOURNAL = LA REVUE DE SANTE DE LA MEDITERRANEE ORIENTALE = AL-MAJALLAH AL-SIHHIYAH LI-SHARQ AL-MUTAWASSIT 2006; 12:909-14. [PMID: 17333839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
This study determined the resistance pattern of Mycobacterium tuberculosis to 4 first-line anti-tuberculosis drugs in children with pulmonary tuberculosis at the Iranian National Research Institute of Tuberculosis and Lung Diseases from 1999 to 2004. There were 350 children with positive cultures over the study period: 7 (2%) were resistant to at least one of the 4 anti-tuberculosis drugs. Primary resistance was detected in 4 cases and secondary resistance in 3 cases. Most cases (6) were among Afghan refugees. Resistance to rifampicin both in primary and secondary resistances was high, showing that children in the Islamic Republic of Iran face the threat of drug-resistant tuberculosis transmission.
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Safavi A, Gholivand MB. Electroanalytical Behaviour of 2-Aminocyclopentene-1-Dithiocarboxylic Acid and Its N-substituted Derivatives at Mercury Electrodes. ANAL LETT 2006. [DOI: 10.1080/00032719208016130] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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34
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Iranpoor N, Firouzabadi H, Safavi A, Shekarriz M. RING OPENING OF EPOXIDES WITH CARBOXYLATES AND PHENOXIDES IN MICELLAR MEDIA CATALYZED WITH Ce(OTf)4. SYNTHETIC COMMUN 2006. [DOI: 10.1081/scc-120005998] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Safavi A, Maleki N, Rostamzadeh A, Maesum S. CCD camera full range pH sensor array. Talanta 2006; 71:498-501. [PMID: 19071333 DOI: 10.1016/j.talanta.2006.04.030] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2005] [Revised: 03/26/2006] [Accepted: 04/06/2006] [Indexed: 11/26/2022]
Abstract
Changes in colors of an array of optical sensors that responds in full pH range were recorded using a CCD camera. The data of the camera were transferred to the computer through a capture card. Simple software was written to read the specific color of each sensor. In order to associate sensor array responses with pH values, a number of different mathematics and chemometrics methods were investigated and compared. The results show that the use of "Microsoft Excel's Solver" provides results which are in very good agreement with those obtained with chemometric methods such as artificial neural network (ANN) and partial least square (PLS) methods.
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Jalessi M, Shahram F, Safavi A, Davatchi F, Nadji A, Jamshid A, Chams C, Gharibdoost F. Tonsillectomy and Behçet’s Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2006. [DOI: 10.1007/0-306-48382-3_95] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Safavi A, Abdollahi H, Mirzajani R. Simultaneous spectrophotometric determination of Fe(III), Al(III) and Cu(II) by partial least-squares calibration method. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2006; 63:196-9. [PMID: 15975847 DOI: 10.1016/j.saa.2005.05.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2004] [Revised: 03/03/2005] [Accepted: 05/08/2005] [Indexed: 05/03/2023]
Abstract
A spectrophotometric method for simultaneous determination of Fe(III), Al(III) and Cu(II) using Alizarin Red S as a chelating agent was developed. The parameters controlling behavior of the system were investigated and optimum conditions were selected. A partial least-squares multivariate calibration method was used for the analysis of ternary mixtures of Fe(III), Al(III) and Cu(II) over the range of 450-6000, 140-4000 and 450-15000 ng ml(-1), respectively. Absorbance data were taken between 400 and 800 nm. Applying this method to simultaneous determination of these metal ions in several synthetic alloy solutions with total relative standard error of less than 5% validated the proposed method.
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Maleki N, Safavi A, Shahbaazi H. Minimizing the Interferences from Adsorption of Substances onto Cell Components in Stripping Voltammetry. ANAL LETT 2005. [DOI: 10.1080/00032710500210501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Safavi A, Sedaghatpour F, Shahbaazi H. Tensammetric Analysis of Nonionic Surfactant Mixtures by Artificial Neural Network. ELECTROANAL 2005. [DOI: 10.1002/elan.200403225] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Maleki N, Safavi A, Shahbaazi H. Electrochemical determination of 2,4-D at a mercury electrode. Anal Chim Acta 2005. [DOI: 10.1016/j.aca.2004.08.058] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Safavi A, Karimi MA, Nezhad MRH. Flow injection analysis of riboflavin with chemiluminescence detection using a N-halo compounds-luminol system. LUMINESCENCE 2005; 20:170-5. [PMID: 15924325 DOI: 10.1002/bio.811] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A chemiluminescent method for the determination of riboflavin is described. The method is based on the chemiluminescence (CL) generated during the oxidation of luminol by N-bromosuccinimide (NBS) and N-chlorosuccinimide (NCS) in alkaline medium. It was found that riboflavin could greatly enhance this CL intensity when present in the luminol solution. Based on this observation, a new flow-injection CL method for the determination of riboflavin is proposed in this paper. The detection limits were 7.5 ng/mL and 3.5 ng/mL of riboflavin for the NBS- and NCS-luminol CL systems, respectively. The relative CL intensity was linear, with riboflavin concentration in the range 19-600 ng/mL and 600-2000 ng/mL for the NBS-luminol CL system, and 12-200 ng/mL and 200-2000 ng/mL for the NCS-luminol CL system. The results obtained for the assay of pharmaceutical preparations compared well with those obtained by the official method and demonstrated good accuracy and precision.
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Safavi A, Abdollahi H, Hormozi Nezhad MR, Kamali R. Cloud point extraction, preconcentration and simultaneous spectrophotometric determination of nickel and cobalt in water samples. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2004; 60:2897-2901. [PMID: 15350927 DOI: 10.1016/j.saa.2004.02.001] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2003] [Accepted: 02/03/2004] [Indexed: 05/24/2023]
Abstract
Cloud point extraction has been used for the preconcentration and simultaneous spectrophotometric determination of nickel and cobalt after the formation of a complex with 2-amino-cyclopentene-1-dithiocarboxylic acid (ACDA), and latter analysis by spectrophotometer using Triton X-114 as surfactant. The parameters affecting the separation phase and detection process were optimized. Under the optimum experimental conditions (i.e. pH=5, 0.07 mM ACDA, Triton X-114=0.25% (w/v)), calibration graphs were linear in the range of 20-500 and 20-200 microg l(-1) with detection limits of 10 and 7.5 microg l(-1) for Ni and Co, respectively. The method was applied to the determination of Ni and Co in natural and waste water samples with satisfactory results.
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Safavi A, Karimi MA, Hormozi Nezhad MR. Flow-injection determination of isoniazid using sodium dichloroisocyanurate- and trichloroisocyanuric acid-luminol chemiluminescence systems. ACTA ACUST UNITED AC 2004; 59:481-6. [PMID: 15178311 DOI: 10.1016/j.farmac.2003.07.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2003] [Accepted: 07/28/2003] [Indexed: 11/19/2022]
Abstract
A chemiluminescent (CL) method for the determination of isoniazid is described. The method is based on the CL generated during the oxidation of luminol by sodium dichloroisocyanurate (SDCC) and trichloroisocyanuric acid (TCCA) in alkaline medium. It was found that isoniazid greatly enhances this CL intensity when present in the luminol solution. Based on this observation, a new flow-injection CL method for the determination of isoniazid has been proposed in this paper. The detection limits were 2 and 3 ng ml(-1) isoniazid for the SDCC-luminol and TCCA-luminol CL systems, respectively. The relative CL intensity was linear with the isoniazid concentration in the range of 4-100 and 100-200 ng ml(-1) for the SDCC-luminol CL system, and 6-200 and 200-1000 ng ml(-1) for the TCCA-luminol CL system. The results obtained for the assay of pharmaceutical preparations compared well with those obtained by the official methods and demonstrated good accuracy and precision.
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Safavi A, Karimi MA, Hormozi Nezhad MR, Kamali R, Saghir N. Sensitive indirect spectrophotometric determination of isoniazid. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2004; 60:765-769. [PMID: 15036086 DOI: 10.1016/s1386-1425(03)00288-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/06/2002] [Revised: 04/21/2003] [Accepted: 06/16/2003] [Indexed: 05/24/2023]
Abstract
A simple, rapid, sensitive and accurate indirect spectrophotometric method for the microdetermination of isoniazid (INH) in pure form and pharmaceutical formulations is developed. The procedure is based on the reaction of copper(II) with isoniazid in the presence of neocuproine (NC). In the presence of neocuproine, copper(II) is reduced easily by isoniazid to a Cu(I)-neocuproine complex, which shows an absorption maximum at 454 nm. By measuring the absorbance of the complex at this wavelength, isoniazid can be determined in the range 0.3-3.5 microgml-1. This method was applied to the determination of isoniazid in pharmaceutical formulation and enabled the determination of the isoniazid in microgram quantities (0.3-3.5 microgml-1). The results obtained for the assay of pharmaceutical preparations compared well with those obtained by the official method and demonstrated good accuracy and precision.
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Jalessi M, Shahram F, Safavi A, Davatchi F, Nadji A, Jamshidi A, Chams C, Gharibdoost F. Tonsillectomy and Behçet's disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 528:471-2. [PMID: 12918746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
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46
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Safavi A, Maleki N, Shahbaazi H. Electrochemical determination of triclosan at a mercury electrode. Anal Chim Acta 2003. [DOI: 10.1016/s0003-2670(03)00920-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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47
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Safavi A, Maleki N, Shams E, Shahbaazi H. Determination of Copper by Adsorptive Stripping Voltammetry of Its Complex with Adenine. ELECTROANAL 2002. [DOI: 10.1002/1521-4109(200207)14:13<929::aid-elan929>3.0.co;2-w] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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48
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Safavi A. Flow injection chemiluminescence determination of sulfide by oxidation with N-bromosuccinimide and N-chlorosuccinimide. Talanta 2002; 57:491-500. [DOI: 10.1016/s0039-9140(02)00048-6] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2001] [Revised: 01/30/2002] [Accepted: 02/04/2002] [Indexed: 11/26/2022]
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49
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Safavi A, Abdollahi H, Bagheri M. Spectral curve deconvolution in micellar systems with H-point curve isolation and H-point standard addition methods. Anal Chim Acta 2002. [DOI: 10.1016/s0003-2670(02)00082-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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50
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Safavi A. Simultaneous kinetic determination of Fe(III) and Fe(II) by H-point standard addition method. Talanta 2002; 56:699-704. [DOI: 10.1016/s0039-9140(01)00635-x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2001] [Revised: 10/29/2001] [Accepted: 10/30/2001] [Indexed: 11/16/2022]
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