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Vinoth S, Wang SF. Lanthanum vanadate-based carbon nanocomposite as an electrochemical probe for amperometric detection of theophylline in real food samples. Food Chem 2023; 427:136623. [PMID: 37364311 DOI: 10.1016/j.foodchem.2023.136623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2023] [Revised: 05/25/2023] [Accepted: 06/11/2023] [Indexed: 06/28/2023]
Abstract
Theophylline (THP) is an emerging drug for chronic obstructive pulmonary disease whose side effects can be greatly affected by caffeine-containing real foods. Because an overdose of this substance can cause respiratory and neurological damage, producing a fast and accurate analytical procedure is critical. Based on a cutting-edge hybrid nanocomposite, this study was used to construct an electrochemical sensor for the accurate detection of THP. Spectroscopy and morphological investigation supported the easy synthesis of tetragonal-LaVO4 (t-LV) nanopellets and LV@CNF hybrid nanocomposite. To detect THP, a highly dispersed LV@CNF nanocomposite was modified on a glassy carbon electrode as a sensing substrate. By amperometric technique, the sensor shows a wide linear range of 0.01-1070 μM, low limit of detection (2.63 nM), and sensitivity (0.228 μA μM-1 cm-2). Finally, the current technique was successfully used to identify THP in real food samples (chocolate, coffee and black tea).
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Affiliation(s)
- Subramaniyan Vinoth
- Department of Materials and Mineral Resources Engineering, National Taipei University of Technology, No. 1, Sec. 3, Chung-Hsiao East Rd., Taipei 106, Taiwan
| | - Sea-Fue Wang
- Department of Materials and Mineral Resources Engineering, National Taipei University of Technology, No. 1, Sec. 3, Chung-Hsiao East Rd., Taipei 106, Taiwan.
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2
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Gañán J, Martínez-García G, Morante-Zarcero S, Pérez-Quintanilla D, Sierra I. Nanomaterials-modified electrochemical sensors for sensitive determination of alkaloids: Recent trends in the application to biological, pharmaceutical and agri-food samples. Microchem J 2022. [DOI: 10.1016/j.microc.2022.108136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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3
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Patil VB, Malode SJ, Mangasuli SN, Tuwar SM, Mondal K, Shetti NP. An Electrochemical Electrode to Detect Theophylline Based on Copper Oxide Nanoparticles Composited with Graphene Oxide. MICROMACHINES 2022; 13:mi13081166. [PMID: 35893164 PMCID: PMC9394302 DOI: 10.3390/mi13081166] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2022] [Revised: 07/18/2022] [Accepted: 07/21/2022] [Indexed: 02/04/2023]
Abstract
The electrochemical analysis of theophylline (THP) was investigated by fabricating a carbon paste electrode (CPE) modified with graphene oxide (GO) along with copper oxide (CuO) nanoparticles (CuO-GO/CPE). The impact of electro-kinetic parameters such as the heterogeneous rate constant, the scan rate, the accumulation time, the pH, the transfer coefficient, and the number of electrons and protons transferred into the electro-oxidation mechanism of THP has been studied utilizing electrochemical methods such as cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The differential pulse voltammetry technique was employed to investigate THP in pharmaceutical and biological samples, confirming the limit of detection (LOD) and quantification (LOQ) of the THP. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analysis were performed to characterize the CuO nanoparticles. The CuO-GO/CPE was more sensitive in THP detection because its electrocatalytic characteristics displayed an enhanced peak current in the 0.2 M supporting electrolyte of pH 6.0, proving the excellent sensing functioning of the modified electrode.
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Affiliation(s)
- Vinoda B. Patil
- Department of Chemistry, Karnatak Science College, Dharwad 580001, Karnataka, India; (V.B.P.); (S.N.M.)
| | - Shweta J. Malode
- Department of Chemistry, School of Advanced Sciences, KLE Technological University, Vidyanagar, Hubballi 580031, Karnataka, India;
| | - Sumitra N. Mangasuli
- Department of Chemistry, Karnatak Science College, Dharwad 580001, Karnataka, India; (V.B.P.); (S.N.M.)
| | - Suresh M. Tuwar
- Department of Chemistry, Karnatak Science College, Dharwad 580001, Karnataka, India; (V.B.P.); (S.N.M.)
- Correspondence: (S.M.T.); (K.M.); (N.P.S.)
| | - Kunal Mondal
- Idaho National Laboratory, Idaho Falls, ID 83415, USA
- Correspondence: (S.M.T.); (K.M.); (N.P.S.)
| | - Nagaraj P. Shetti
- Department of Chemistry, School of Advanced Sciences, KLE Technological University, Vidyanagar, Hubballi 580031, Karnataka, India;
- Correspondence: (S.M.T.); (K.M.); (N.P.S.)
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4
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Oxidative Degradation of Pharmaceutical Waste, Theophylline, from Natural Environment. ATMOSPHERE 2022. [DOI: 10.3390/atmos13050835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
The elimination of organic contaminants from natural resources is extremely important to ensure their (re-)usability. In this report, the degradation of a model pharmaceutical compound, theophylline, is compared between natural and laboratory-controlled environments. While the concentration of H2O2 variably affected the degradation efficiency (approximately from 8 to 20 min for complete degradation) in the photo-irradiation experiments, the inorganic compounds (NaNO3, KH2PO4 and ZnSO4) present in the medium seemed to affect the degradation by scavenging hydroxyl radicals (•OH). The end-product studies using high-resolution mass spectrometry (HRMS) ruled out the involvement of secondary radicals in the degradation mechanism. The quantitative calculation with the help of authentic standards pointed out the predominant role of hydroxylation pathways, especially in the initial stages. Although a noticeable decline in the degradation efficiency was observed in river water samples (complete degradation after 25 min with an approximately 20% total organic carbon (TOC) removal), appreciable TOC removal (70%) was eventually achieved after prolonged irradiation (1 h) and in the presence of additional H2O2 (5 times), revealing the potential of our technique. The results furnished in this report could be considered as a preliminary step for the construction of •OH-based wastewater treatment methodologies for the remediation of toxic pollutants from the real environment.
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Shao J, Wang C, Shen Y, Shi J, Ding D. Electrochemical Sensors and Biosensors for the Analysis of Tea Components: A Bibliometric Review. Front Chem 2022; 9:818461. [PMID: 35096777 PMCID: PMC8795770 DOI: 10.3389/fchem.2021.818461] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 12/28/2021] [Indexed: 12/25/2022] Open
Abstract
Tea is a popular beverage all around the world. Tea composition, quality monitoring, and tea identification have all been the subject of extensive research due to concerns about the nutritional value and safety of tea intake. In the last 2 decades, research into tea employing electrochemical biosensing technologies has received a lot of interest. Despite the fact that electrochemical biosensing is not yet the most widely utilized approach for tea analysis, it has emerged as a promising technology due to its high sensitivity, speed, and low cost. Through bibliometric analysis, we give a systematic survey of the literature on electrochemical analysis of tea from 1994 to 2021 in this study. Electrochemical analysis in the study of tea can be split into three distinct stages, according to the bibliometric analysis. After chromatographic separation of materials, electrochemical techniques were initially used only as a detection tool. Many key components of tea, including as tea polyphenols, gallic acid, caffeic acid, and others, have electrochemical activity, and their electrochemical behavior is being investigated. High-performance electrochemical sensors have steadily become a hot research issue as materials science, particularly nanomaterials, and has progressed. This review not only highlights these processes, but also analyzes and contrasts the relevant literature. This evaluation also provides future views in this area based on the bibliometric findings.
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Affiliation(s)
- Jinhua Shao
- School of Chemistry and Bioengineering, Hunan University of Science and Engineering, Yongzhou, China
| | - Chao Wang
- School of Chemistry and Bioengineering, Hunan University of Science and Engineering, Yongzhou, China
| | - Yiling Shen
- School of Chemistry and Bioengineering, Hunan University of Science and Engineering, Yongzhou, China
| | - Jinlei Shi
- School of Chemistry and Bioengineering, Hunan University of Science and Engineering, Yongzhou, China
| | - Dongqing Ding
- School of Chemistry and Bioengineering, Hunan University of Science and Engineering, Yongzhou, China
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Bhargava A, Bansal A, Goyal V, Bansal P. A review on tea quality and safety using emerging parameters. JOURNAL OF FOOD MEASUREMENT AND CHARACTERIZATION 2022. [DOI: 10.1007/s11694-021-01232-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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7
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Nano optical and electrochemical sensors and biosensors for detection of narrow therapeutic index drugs. Mikrochim Acta 2021; 188:411. [PMID: 34741213 DOI: 10.1007/s00604-021-05003-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 08/24/2021] [Indexed: 01/02/2023]
Abstract
For the first time, a comprehensive review is presented on the quantitative determination of narrow therapeutic index drugs (NTIDs) by nano optical and electrochemical sensors and biosensors. NTIDs have a narrow index between their effective doses and those at which they produce adverse toxic effects. Therefore, accurate determination of these drugs is very important for clinicians to provide a clear judgment about drug therapy for patients. Routine analytical techniques have limitations such as being expensive, laborious, and time-consuming, and need a skilled user and therefore the nano/(bio)sensing technology leads to high interest.
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8
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Crapnell RD, Banks CE. Electroanalytical overview: The electroanalytical detection of theophylline. TALANTA OPEN 2021. [DOI: 10.1016/j.talo.2021.100037] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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Guan Q, Guo H, Xue R, Wang M, Wu N, Cao Y, Zhao X, Yang W. Electrochemical sensing platform based on covalent organic framework materials and gold nanoparticles for high sensitivity determination of theophylline and caffeine. Mikrochim Acta 2021; 188:85. [DOI: 10.1007/s00604-021-04744-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 02/03/2021] [Indexed: 02/07/2023]
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11
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Keyvanfard M, Karimi-Maleh H, Karimi F, Opoku F, Kiarii EM, Govender PP, Taghavi M, Fu L, Aygun A, Sen F. Electro-catalytic amplified sensor for determination of N-acetylcysteine in the presence of theophylline confirmed by experimental coupled theoretical investigation. Sci Rep 2021; 11:1006. [PMID: 33441706 PMCID: PMC7806823 DOI: 10.1038/s41598-020-79872-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 11/26/2020] [Indexed: 01/08/2023] Open
Abstract
The 1,l/-bis(2-phenylethan-1-ol)ferrocene, 1-butyl-3-methylimidazolium hexafluoro phosphate (BMPF6) and NiO-SWCNTs were used to modify carbon paste electrode (BPOFc/BMPF6/NiO-SWCNTs/CPE), which could act as an electro-catalytic tool for the analysis of N-acetylcysteine in this work. The BPOFc/BMPF6/NiO-SWCNTs/CPE with high electrical conductivity showed two completely separate signals with oxidation potentials of 432 and 970 mV for the first time that is sufficient for the determination of N-acetylcysteine in the presence of theophylline. The BPOFc/BMPF6/NiO-SWCNTs/CPE showed linear dynamic ranges of 0.02–300.0 μM and 1.0–350.0 μM with the detection limit of ~ 8.0 nM and 0.6 μM for the measurement of N-acetylcysteine and theophylline, respectively. In the second part, understanding the nature of interaction, quantum conductance modulation, electronic properties, charge density, and adsorption behavior of N-acetylcysteine on NiO–SWCNTs surface from first-principle studies through the use of theoretical investigation is vital for designing high-performance sensor materials. The N-acetylcysteine molecule was chemisorbed on the NiO–SWCNTs surface by suitable adsorption energies (− 1.102 to − 5.042 eV) and reasonable charge transfer between N-acetylcysteine and NiO–SWCNTs.
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Affiliation(s)
- Mohsen Keyvanfard
- Department of Chemistry, Majlesi Branch, Islamic Azad University, Majlesi, Iran.
| | - Hassan Karimi-Maleh
- School of Resources and Environment, University of Electronic Science and Technology of China, Xiyuan Ave, Chengdu, 611731, People's Republic of China. .,Department of Chemical Engineering, Quchan University of Technology, Quchan, Iran. .,Department of Chemistry, University of Johannesburg, P.O. Box 17011, Doornfontein Campus, Johannesburg, 2028, South Africa.
| | - Fatemeh Karimi
- School of Resources and Environment, University of Electronic Science and Technology of China, Xiyuan Ave, Chengdu, 611731, People's Republic of China. .,Department of Chemical Engineering, Quchan University of Technology, Quchan, Iran.
| | - Francis Opoku
- Department of Chemistry, University of Johannesburg, P.O. Box 17011, Doornfontein Campus, Johannesburg, 2028, South Africa
| | - Ephraim Muriithi Kiarii
- Department of Chemistry, University of Johannesburg, P.O. Box 17011, Doornfontein Campus, Johannesburg, 2028, South Africa
| | - Poomani Penny Govender
- Department of Chemistry, University of Johannesburg, P.O. Box 17011, Doornfontein Campus, Johannesburg, 2028, South Africa
| | - Mehdi Taghavi
- Polymer Chemistry Research Laboratory, Faculty of Science, Shahid Chamran University, 61357-43337, Ahvaz, Iran
| | - Li Fu
- College of Materials and Environmental Engineering, Hangzhou Dianzi University, Hangzhou, 310018, China
| | - Aysenur Aygun
- Sen Research Group, Biochemistry Department, Faculty of Arts and Science, Dumlupınar University, Evliya Çelebi Campus, 43100, Kütahya, Turkey
| | - Fatih Sen
- Sen Research Group, Biochemistry Department, Faculty of Arts and Science, Dumlupınar University, Evliya Çelebi Campus, 43100, Kütahya, Turkey
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Affiliation(s)
- Sairaman Saikrithika
- Nano and Bioelectrochemistry Research Laboratory, Department of Chemistry, School of Advanced Sciences Vellore Institute of Technology Vellore 632 014, Tamil Nadu India
| | - Annamalai Senthil Kumar
- Nano and Bioelectrochemistry Research Laboratory, Department of Chemistry, School of Advanced Sciences Vellore Institute of Technology Vellore 632 014, Tamil Nadu India
- Carbon dioxide and Green Technology Research Centre Vellore Institute of Technology University Vellore 632 014, Tamil Nadu India
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Rezvani SA, Soleymanpour A. Application of a sensitive electrochemical sensor modified with WO3 nanoparticles for the trace determination of theophylline. Microchem J 2019. [DOI: 10.1016/j.microc.2019.104005] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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14
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Gan T, Li J, Zhao A, Xu J, Zheng D, Wang H, Liu Y. Detection of theophylline using molecularly imprinted mesoporous silica spheres. Food Chem 2018; 268:1-8. [DOI: 10.1016/j.foodchem.2018.06.058] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2018] [Revised: 06/09/2018] [Accepted: 06/12/2018] [Indexed: 12/31/2022]
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Simultaneous determination of theophylline and caffeine on novel [Tetra-(5-chloroquinolin-8-yloxy) phthalocyanato] manganese(III)-Carbon nanotubes composite electrode. Talanta 2018; 184:452-460. [PMID: 29674068 DOI: 10.1016/j.talanta.2018.03.029] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Revised: 03/09/2018] [Accepted: 03/11/2018] [Indexed: 01/05/2023]
Abstract
This work reports the synthesis of new symmetrically substituted manganese(III) phthalocyanine (2eOHMnPc) (2) containing tetra 5-chloroquinolin-8-yloxy group at the peripheral position for the first time. Manganese(III) phthalocyanine (2) was synthesized by cyclotetramerization of 4-(5-chloroquinolin-8-yloxy)phthalonitrile (1) in the presence of corresponding metal salt (manganese(II) chloride). This peripherally substituted phthalocyanine complex (2) was purified by column chromatography and characterized by several techniques such as IR, mass and UV-Visible spectral data. This novel synthesized phthalocyanine was mixed with multiwalled carbon nanotubes in order to prepare the novel catalytic surface on glassy carbon electrode for theophylline and caffeine detection in acidic medium. The novel composite electrode surfaces were characterized by scanning electron microscopy and electrochemical impedance spectroscopy. Individual and simultaneous determination of theophylline and caffeine were studied by differential pulse voltammetry. The detection limits were individually calculated for theophylline and caffeine as 6.6 × 10-9 M and 5.0 × 10-8 M, respectively. In simultaneous determination, LODs were calculated for theophylline and caffeine as 8.1 × 10-9 M and 3.0 × 10-7 M, respectively. The practical applicability of the proposed modified electrode was tested for the determination of theophylline and caffeine in green tea, cola and theophylline serum.
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Wang Y, Ding Y, Li L, Hu P. Nitrogen-doped carbon nanotubes decorated poly (L-Cysteine) as a novel, ultrasensitive electrochemical sensor for simultaneous determination of theophylline and caffeine. Talanta 2018; 178:449-457. [DOI: 10.1016/j.talanta.2017.08.076] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Revised: 08/20/2017] [Accepted: 08/24/2017] [Indexed: 12/25/2022]
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Ngamchuea K, Chaisiwamongkhol K, Batchelor-McAuley C, Compton RG. Chemical analysis in saliva and the search for salivary biomarkers – a tutorial review. Analyst 2018; 143:81-99. [DOI: 10.1039/c7an01571b] [Citation(s) in RCA: 84] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A review of the uses of saliva biomarkers, detection methods and requirements for new biomarkers.
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Affiliation(s)
- Kamonwad Ngamchuea
- Department of Chemistry
- Physical & Theoretical Chemistry Laboratory
- University of Oxford
- Oxford
- UK
| | - Korbua Chaisiwamongkhol
- Department of Chemistry
- Physical & Theoretical Chemistry Laboratory
- University of Oxford
- Oxford
- UK
| | | | - Richard G. Compton
- Department of Chemistry
- Physical & Theoretical Chemistry Laboratory
- University of Oxford
- Oxford
- UK
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Hooshmand S, Es’haghi Z. Simultaneous quantification of arginine, alanine, methionine and cysteine amino acids in supplements using a novel bioelectro-nanosensor based on CdSe quantum dot/modified carbon nanotube hollow fiber pencil graphite electrode via Taguchi method. J Pharm Biomed Anal 2017; 146:226-235. [DOI: 10.1016/j.jpba.2017.08.034] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 08/18/2017] [Accepted: 08/27/2017] [Indexed: 01/22/2023]
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19
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Microfabricated disposable nanosensor based on CdSe quantum dot/ionic liquid-mediated hollow fiber-pencil graphite electrode for simultaneous electrochemical quantification of uric acid and creatinine in human samples. Anal Chim Acta 2017; 972:28-37. [DOI: 10.1016/j.aca.2017.04.035] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Revised: 04/04/2017] [Accepted: 04/07/2017] [Indexed: 11/20/2022]
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20
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Yang YJ, Guo L, Zhang W. The electropolymerization of CTAB on glassy carbon electrode for simultaneous determination of dopamine, uric acid, tryptophan and theophylline. J Electroanal Chem (Lausanne) 2016. [DOI: 10.1016/j.jelechem.2016.02.043] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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21
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Yang G, Zhao F, Zeng B. Facile fabrication of a novel anisotropic gold nanoparticle–chitosan–ionic liquid/graphene modified electrode for the determination of theophylline and caffeine. Talanta 2014; 127:116-22. [DOI: 10.1016/j.talanta.2014.03.029] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Revised: 03/11/2014] [Accepted: 03/13/2014] [Indexed: 10/25/2022]
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22
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Sunil Paul MM, Aravind UK, Pramod G, Saha A, Aravindakumar CT. Hydroxyl radical induced oxidation of theophylline in water: a kinetic and mechanistic study. Org Biomol Chem 2014; 12:5611-20. [PMID: 24957195 DOI: 10.1039/c4ob00102h] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Oxidative destruction and mineralization of emerging organic pollutants by hydroxyl radicals (˙OH) is a well established area of research. The possibility of generating hazardous by-products in the case of ˙OH reaction demands extensive investigations on the degradation mechanism. A combination of pulse radiolysis and steady state photolysis (H2O2/UV photolysis) followed by high resolution mass spectrometric (HRMS) analysis have been employed to explicate the kinetic and mechanistic features of the destruction of theophylline, a model pharmaceutical compound and an identified pollutant, by ˙OH in the present study. The oxidative destruction of this molecule, for intermediate product studies, was initially achieved by H2O2/UV photolysis. The transient absorption spectrum corresponding to the reaction of ˙OH with theophylline at pH 6, primarily caused by the generation of (T8-OH)˙, was characterised by an absorption band at 330 nm (k2 = (8.22 ± 0.03) × 10(9) dm(3) mol(-1) s(-1)). A significantly different spectrum (λmax: 340 nm) was observed at highly alkaline pH (10.2) due to the deprotonation of this radical (pKa∼ 10.0). Specific one electron oxidants such as sulphate radical anions (SO4˙(-)) and azide radicals (N3˙) produce the deprotonated form (T(-H)˙) of the radical cation (T˙(+)) of theophylline (pKa 3.1) with k2 values of (7.51 ± 0.04) × 10(9) dm(3) mol(-1) s(-1) and (7.61 ± 0.02) × 10(9) dm(3) mol(-1) s(-1) respectively. Conversely, oxide radicals (O˙(-)) react with theophylline via a hydrogen abstraction protocol with a rather slow k2 value of (1.95 ± 0.02) × 10(9) dm(3) mol(-1) s(-1). The transient spectral studies were complemented by the end product profile acquired by HRMS analysis. Various transformation products of theophylline induced by ˙OH were identified by this technique which include derivatives of uric acids (i, iv & v) and xanthines (ii, iii & vi). Further breakdown of the early formed product due to ˙OH attack leads to ring opened compounds (ix-xiv). The kinetic and mechanistic data furnished in the present study serve as a basic frame work for the construction of ˙OH induced water treatment systems as well as to understand the biological implications of compounds of this kind.
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Affiliation(s)
- M M Sunil Paul
- School of Environmental Sciences, Mahatma Gandhi University, Kottayam, India.
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MansouriMajd S, Teymourian H, Salimi A, Hallaj R. Fabrication of electrochemical theophylline sensor based on manganese oxide nanoparticles/ionic liquid/chitosan nanocomposite modified glassy carbon electrode. Electrochim Acta 2013. [DOI: 10.1016/j.electacta.2013.07.029] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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24
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Simultaneous determination of theophylline and caffeine by large mesoporous carbon/Nafion modified electrode. J Electroanal Chem (Lausanne) 2013. [DOI: 10.1016/j.jelechem.2013.07.030] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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25
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Sensitive and Efficient Electrochemical Determination of Kojic Acid in Foodstuffs Based on Graphene-Pt Nanocomposite-Modified Electrode. FOOD ANAL METHOD 2013. [DOI: 10.1007/s12161-013-9604-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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