76
|
Jerajani HR, Kumar AS, Kuruvila M, Nataraja HV, Philip M, Pratap DVS, Sumathy TK, Krishnankutty B, Dhawan S, Thomas D. Efficacy and safety of topical halometasone in eczematous dermatoses in Indian population: an open label, noncomparative study. Indian J Dermatol 2012; 56:652-6. [PMID: 22345764 PMCID: PMC3276890 DOI: 10.4103/0019-5154.91822] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
BACKGROUND Topical steroids remain the mainstay of treatment in eczema, an inflammatory skin reaction characterized by pruritus, redness, scaling, and clustered oozing papulovesicles. Halometasone is a new potent corticosteroid approved in the Indian market for topical application in the treatment of dermatitis. AIMS To evaluate the efficacy and safety of halometasone in the treatment of acute or chronic noninfected eczematous dermatosis in Indian population. MATERIALS AND METHODS A prospective, open, multicentric, phase 3, noncomparative clinical trial conducted at outpatient departments of seven centres. Two hundred endogenous eczema patients meeting study criteria were enrolled. Halometasone 0.05% cream was applied twice daily for 30 days in chronic and 20 days in acute eczema patients. Calculation of eczema area and severity index, and assessment of investigator's global assessment of severity of eczema and severity of pruritus score were done at each visit and compared with baseline. All adverse events (AE) were captured and documented. Laboratory investigations including haematological tests, urinalysis, renal and liver function tests were performed at baseline and at end of treatment. RESULTS Of the 200 patients enrolled, 180 were chronic and 20 were acute eczema patients. It was found that there was a significant (P<0.001) improvement in all efficacy parameters compared with baseline. The treatment was shown to be successful in 91% patients. AE were reported in 30 patients and there was no serious AE reported. There was no clinically significant difference in laboratory investigations with treatment. CONCLUSIONS Halometasone was shown to be safe and very effective in Indian patients with acute and chronic eczema and the drug was well tolerated.
Collapse
|
77
|
Ahmed K, Singh H, Kumar AS, Ahmed I. A case of a large verrucous swelling over the scrotum. Indian J Sex Transm Dis AIDS 2012. [PMID: 23188943 PMCID: PMC3505295 DOI: 10.4103/2589-0557.102133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
|
78
|
Kumar AS, Swetha P. Simple adsorption of anthraquinone on carbon nanotube modified electrode and its efficient electrochemical behaviors. Colloids Surf A Physicochem Eng Asp 2011. [DOI: 10.1016/j.colsurfa.2011.05.010] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
79
|
Kumar AS, Kumar S, Abraham S, Rao PSS. Leprosy among tribal population of Chhattisgarh state, India. INDIAN JOURNAL OF LEPROSY 2011; 83:23-29. [PMID: 21638980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Chhattisgarh state is still endemic for leprosy and has a large tribal population. During 2003-2009, a total of 1530 untreated leprosy cases reported to the Leprosy Mission Referral Hospital in Champa, of which 151(9%) were classified as belonging to the scheduled tribes. The characteristics of these new tribal patients are described and compared with other patients and to the demographics of the tribals in the general population of the State. While tribals were accessing the leprosy services similar to the other social groups, the delay in reporting, high BI and other features pose more serious problems in the transmission of leprosy and in management of complications due to the harsh environment and occupational patterns of the tribals. Appropriate strategies and more community based approaches will be necessary if these groups are also targeted for eradication of leprosy.
Collapse
|
80
|
Barathi P, Senthil Kumar A, Karthick MRB. Polynuclear Nickel Hexacyanoferrate/Graphitized Mesoporous Carbon Hybrid Chemically Modified Electrode for Selective Hydrazine Detection. INTERNATIONAL JOURNAL OF ELECTROCHEMISTRY 2011. [DOI: 10.4061/2011/386023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A hybrid polynuclear nickel hexacyanoferrate (NiHCFe)/graphitized mesoporous carbon- (GMC-) modified glassy carbon electrode (GCE/NiHCFe@GMC) has been prepared by a sequential method using electrodeposited Ni on a GMC-modified glassy carbon electrode (GCE/Ni@GMC) as a template and [Fe(CN)6]3−as anin-situchemical precipitant, without any additional interlinking agent. Physicochemical and electrochemical characterizations reveal the presence of NiHCFe units within the porous sites of the GMC. The GCE/NiHCFe@GMC electrode showed highly stable and well-defined redox behaviors with surface-confined electron-transfer mechanism in a pH 7 phosphate buffer solution. The GCE/NiHCFe@GMC showed about 20 times enhancement in hydrazine oxidation peak current along with 500 mV reduction in overpotential over the corresponding unmodified GCE/GMC. Hydrazine calibration plots by CV and amperometrici-tmethods were linear up to 1 mM and 220 μM with current sensitivity values of 15.86 μA/mM and 7.37 nA/μM, respectively. Calculated detection limit by the amperometrici-tmethod was 23.2 nM. The hybrid GCE/NiHCFe@GMC exhibits remarkable tolerance to important industrial and biological interferents. Finally determination of hydrazine in cigarette smoke sample was successfully demonstrated.
Collapse
|
81
|
Chiu MH, Kumar AS, Sornambikai S, Zen JM, Shih Y. Flow Injection Analysis of Aluminum Chlorohydrate in Antiperspirant Deodorants Using a Built-in Three-in-one Screen-Printed Silver Electrode. ELECTROANAL 2010. [DOI: 10.1002/elan.200900635] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
82
|
Prashant S, Kumar AS, Basheeruddin DDM, Chowdhary TN, Madhu B. Cutaneous manifestations in patients suspected of chikungunya disease. Indian J Dermatol 2010; 54:128-31. [PMID: 20101307 PMCID: PMC2807151 DOI: 10.4103/0019-5154.53186] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Context: An epidemic of chikungunya disease occurred in India during late 2005 through 2006 affecting nearly 1,400,000 people. Aim: To study the cutaneous manifestations in suspected cases of chikungunya disease. Settings and Design: Patients who attended our outpatient departments from January 2006 to September 2006 were prospectively included if they had symptoms of chikungunya disease according to the ‘case definition’ of the National Institute of Communicable Diseases, Directorate General of Health Services, Government of India. The criteria were an acute illness characterized by the sudden onset of fever and several symptoms such as joint pain, headache, backache, photophobia, and eruption during an epidemic of chikungunya fever in the absence of confirmatory serological tests. Materials and Methods: A total of 115 patients (65 men and 50 women) who satisfied the above criteria were enrolled for the study. Results: An erythematous maculopapular rash subsiding without any sequelae in 3-4 days was the most common cutaneous finding in our patients. Genital ulcers distributed predominantly over the scrotum and base of the penile shaft in men and labia majora in women were the second most common manifestation. Other manifestations included tenderness/edema of hands and feet, grouped hyperpigmented macules over the nose and cheeks, fixed drug eruptions, erythema nodosum, erythema multiformae, generalized urticarial eruptions, and flare up of pre-existing psoriasis and lichen planus. Conclusions: To conclude, a plethora of cutaneous manifestations were noted in suspected cases of chikungunya disease. Genital ulcers, to the best of our knowledge, have not been reported during the earlier epidemics but have been reported by others during the present one.
Collapse
|
83
|
Kumar AS, Swetha P. Electrochemical-assisted encapsulation of catechol on a multiwalled carbon nanotube modified electrode. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2010; 26:6874-7. [PMID: 20411948 DOI: 10.1021/la100462r] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Electrochemical-assisted encapsulation of a neurotransmitter, catechol (CA), as nanoaggregates on a multiwalled carbon nanotube (>90% of carbon basis MWNT) modified gold electrode (Au/CA@CNT) has been demonstrated without any derivatization or electrode preactivation procedures. Characterization of the CA@CNT by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared attenuated total reflection (FTIR/ATR) spectroscopy, and cyclic voltammetry (CV) collectively revealed stable encapsulation of the CA within strained and misalignment areas of the MWNT capsule. The Au/CA@CNT shows a couple of redox peaks centered at 0 (A1/C1) and 200 mV vs Ag/AgCl (A2/C2) due to the encapsulated (chemisorbed) and physisorbed CA moieties, respectively. The calculated chemisorbed catechol surface excess, Gamma(CA), value was 98.3 x 10(-10) mol x cm(-2). Control solution phase preparations of CA@CNTs yielded poor loading and instability problems, if it is chemically modified on the gold electrode. Electrochemical mediated oxidation of hydrazine on the Au/CA@CNT was demonstrated with an approximately 20 times increase in peak current and 200 mV reduction in the overpotential values in a pH 7 phosphate buffer solution.
Collapse
|
84
|
Kumar AS, Sornambikai S, Gayathri P, Zen JM. Selective covalent immobilization of catechol on activated carbon electrodes. J Electroanal Chem (Lausanne) 2010. [DOI: 10.1016/j.jelechem.2009.12.016] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
85
|
Kumar AS, Sornambikai S, Deepika L, Zen JM. Highly selective immobilization of amoxicillin antibiotic on carbon nanotube modified electrodes and its antibacterial activity. ACTA ACUST UNITED AC 2010. [DOI: 10.1039/c0jm02262d] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
86
|
Kumar AS, Tanase T, Zen JM. Chemically modified electrode with a film of nano ruthenium oxides stabilizing high valent RuO(4)(-) species and its redox-selective sequential transformation to polynuclear ruthenium oxide-metallocyanates. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:13633-13640. [PMID: 19928948 DOI: 10.1021/la902228h] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
High-valent Ru(VII)O(4)(-) (perruthenate) is a short-lived species in aqueous solutions (pH 1-14) and has scarcely been studied through electrochemistry. By a potential-controlled oxidative deposition method at 1 V vs Ag/AgCl using RuCl(3) in a pH 2 KCl-HCl buffer solution, chemically modified glassy carbon (GCE) and indium tin oxide (ITO) electrodes were successfully prepared with a film of hydrous nano ruthenium oxides RuO(2) and RuO(3), stabilizing the high-valent perruthenate anion (Ru(VII)-RuO(x)-CME, x = 2 and 3, CME = chemically modified electrode). The electrodes showed three distinct redox peaks corresponding to Ru(2)O(3)/RuO(2), RuO(2)/RuO(3), and RuO(4)(2-)/RuO(4)(-) redox processes at pH 2, like the classical RuO(2) electrodes in alkaline conditions. Solid state UV-visible spectra of the ITO/Ru(VII)-RuO(x)-CME showed characteristic absorption very close to chemically generated authentic RuO(4)(-) species in alkaline solution. Further, redox-controlled sequential procedures yielded polynuclear ruthenium oxide-hexacyanometallate films (RuO-MCN-CME, M = Fe and Ru), in which Ru(VII)-RuO(x)-CME acted as a specific template. A controlled-potential activation (>1 V) of Ru(VII)-RuO(x)-CME, stabilizing the key RuO(4)(-) species, in a solution of [Fe(CN)(6)](3-) or [Ru(CN)(6)](4-), should be a critical step for the formation of polynuclear RuO-MCN matrix.
Collapse
|
87
|
Garwood ER, Kumar AS, Baehner F, Garber JE, Troyan S, Olopade OI, Moore D, Au A, Flowers C, Campbell M, Hylton N, Esserman LJ, Rush-Port E. Fluvastatin has biologic effects on stage 0 and 1 breast cancer. Cancer Res 2009. [DOI: 10.1158/0008-5472.sabcs-4122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Abstract #4122
Introduction: Statins are safe, reduce cardiovascular risk, and impact pathways critical to cancer progression. We and others have shown lipophilic statins cause apoptosis and growth suppression in vitro and in vivo, and though epidemiologic data are mixed, statin effect appears most evident in estrogen receptor (ER) negative or grade 3 disease. To look for a direct biologic effect of lipophilic statins, we conducted a perioperative pilot window trial in women with breast cancer (BC).
 Methods: 40 subjects with stage 0,1 BC were randomized to high dose (80mg/day) or low dose (20mg/day) fluvastatin for 3-6 weeks prior to surgery. Paired tissue (core biopsy and surgical specimen), peripheral blood and MRI were obtained. Primary endpoint was Ki-67 (proliferation) change. Secondary endpoints included cleaved caspase-3 (CC3, apoptosis), longest diameter (LD) by MRI, and C-reactive protein (CRP) change. Subgroup analyses was planned by grade (3 vs. 1,2), statin dose; and ER status. Immunohistochemistry (IHC) on paraffin tissue used standard streptavidin biotin methods. A single breast pathologist reviewed all slides; a single radiologist read all MRIs, both blinded to timepoint.
 Results: Median serum cholesterol decreased by 16% (-23% and -12% for high and low dose, respectively p=0.012), indicating drug effect and compliance. 29 patients had sufficient tumor for paired IHC, 14 and 15 were grade 3 and 1,2, and 10 and 19 were ER - and +, respectively. In grade 3 (73% of which were ER-) vs. 1,2 tumors, there was a significant decrease in Ki-67, -7.2% (interquartile range (IQR) -13.4%, 0% ) vs. -0.3% (IQR -3%, .8%), respectively, p=0.04. CC3 (apoptosis) increased, 60% vs. 13% for grade 3 vs. 1,2 tumors, respectively, p=0.015. ER- and ER+ cases had a similar reduction in Ki67 with a median drop of 2% (IQR -13.4%, 1%) and 1.2% (IQR -6.6%,0.8%), respectively, p=0.56. While CC3 was increased in ER- vs. + (55% vs. 29%), the difference was not statistically significant. There was no dose dependent effect on Ki-67or CC3.There was no evidence of Ki67 or CC3 change when all grades were analyzed together (median drop 1.2%) and no change in CRP. Of 14 subjects with paired MRIs, 4 grade 3 cases showed a significant decrease in LD, marked ductal dilatation and increased necrosis.with statin exposure.
 Conclusions: A lipophilic statin, fluvastatin, reduced cholesterol and had measurable biologic changes (reduced proliferation, size and increased apoptosis) in stage 0,1 BC after only 3-6 weeks of exposure, specifically in the grade 3 subset. Results support the study of statins for chemoprevention for women at risk for or with stage 0 grade 3 BC, where new agents are needed.
Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 4122.
Collapse
|
88
|
Kumar AS, Tanase T, Iida M. In situ nanostructure formation of (micro-hydroxo)bis(micro-carboxylato) diruthenium units in nafion membrane and its utilization for selective reduction of nitrosonium ion in aqueous medium. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:391-4. [PMID: 17209583 DOI: 10.1021/la0623578] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Nanostructured molecular film containing the (micro-hydroxo)bis(micro-carboxylato) diruthenium(III) units, [RuIII2(micro-OH)(micro-CH3COO)2(HBpz3)2]+ ({RuIII2(micro-OH)}), was prepared by an in situ conversion of its micro-oxo precursor, [RuIII2(micro-O)(micro-CH3COO)2(HBpz3)2] ({RuIII2(micro-O)}), in a Nafion membrane matrix, where HBpz3 is hydrotris(1-pyrazolyl)borate. The conversion procedure results in fine nanoparticle aggregates of the {RuIII2(micro-OH)} units in the Nafion membrane (Nf-{RuIII2(micro-OH)}), where an average particle size (4.1 +/- 2.3 nm) is close to the Nafion's cluster dimension of approximately 4 nm. Chemically modified electrodes by using the Nafion molecular membrane films (Nf-{RuIII2(micro-OH)}-MMFEs) were further developed on ITO/glass and glassy carbon electrode (GCE) surfaces, and a selective reduction of nitrosonium ion (NO+), presumably through reaction of a {RuIIRuIII(micro-OH)} mixed-valence state with HNO2, was demonstrated without interference by molecular oxygen in an acidic aqueous solution. The Nf-{RuIII2(micro-OH)}-MMFEs are stable even in a physiological condition (pH 7), where the naked {RuIII2(-OH)} complex is readily transformed into its deprotonated {RuIII2(micro-O)} form, demonstrating an unusual stabilizing effects for the {RuIII2(micro-OH)} unit by the Nafion cluster environment.
Collapse
|
89
|
Kumar AS, Zen JM. Characteristic and electrocatalytic behavior of ruthenium Prussian blue analogue film in strongly acidic media. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/j.molcata.2006.02.038] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
90
|
Tsai DM, Kumar AS, Zen JM. A highly stable and sensitive chemically modified screen-printed electrode for sulfide analysis. Anal Chim Acta 2006; 556:145-50. [PMID: 17723341 DOI: 10.1016/j.aca.2005.05.038] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2005] [Revised: 05/15/2005] [Accepted: 05/17/2005] [Indexed: 10/25/2022]
Abstract
We report here a highly stable and sensitive chemically modified screen-printed carbon electrode (CMSPE) for sulfide analysis. The CMSPE was prepared by first ion-exchanging ferricyanide into a Tosflex anion-exchange polymer and then sealing with a tetraethyl orthosilicate sol-gel layer. The sol-gel overlayer coating was crucial to stabilize the electron mediator (i.e., Fe(CN)6(3-)) from leaching. The strong interaction between the oxy-hydroxy functional group of sol-gel and the hydrophilic sites of Tosflex makes the composite highly rigid to trap the ferricyanide mediator. An obvious electrocatalytic sulfide oxidation current signal at approximately 0.20 V versus Ag/AgCl in pH 7 phosphate buffer solution was observed at the CMSPE. A linear calibration plot over a wide range of 0.1 microM to 1mM with a slope of 5.6 nA/muM was obtained by flow injection analysis. The detection limit (S/N=3) was 8.9 nM (i.e., 25.6 ppt). Practical utility of the system was applied to the determination of sulfide trapped from cigarette smoke and sulfide content in hot spring water.
Collapse
|
91
|
Hsu CT, Chung HH, Lyuu HJ, Tsai DM, Kumar AS, Zen JM. An Electrochemical Cell Coupled with Disposable Screen-Printed Electrodes for Use in Flow Injection Analysis. ANAL SCI 2006; 22:35-8. [PMID: 16429769 DOI: 10.2116/analsci.22.35] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
An electrochemical cell coupled with disposable screen-printed electrodes (SPEs) that is specifically designed for use in flow injection analysis (FIA) is described in this study. The cell is made of foldable polyoxymethylene (acetal) thick platelets with the bottom portion consisting of a cavity track to drag the SPEs in position and the top portion having predrilled T-like holes to arrange the Ag/AgCl reference electrode and stainless steel inlet & outlet. An "O ring" is suitably fixed on the top of the working electrode to form a thin-layer space where the electrochemical reaction can take place. Hydrodynamic characterization was validated by using a benchmark hexacyanoferrate redox couple. The results of practical analysis of glucose in human plasma clearly demonstrate the characteristics and applicability of the proposed wall-jet electrochemical cell in FIA.
Collapse
|
92
|
Shih Y, Senthil Kumar A, Zen JM, Hsu JC. Detection of Hidden Mercury in Cosmetic Products by Partially Cross-Linked Poly(4-vinylpyridine)/Screen-Printed Electrode. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2005. [DOI: 10.1246/bcsj.78.2130] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
93
|
Yang CC, Kumar AS, Zen JM. Precise blood lead analysis using a combined internal standard and standard addition approach with disposable screen-printed electrodes. Anal Biochem 2005; 338:278-83. [PMID: 15745748 DOI: 10.1016/j.ab.2004.12.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2004] [Indexed: 10/25/2022]
Abstract
We report here a highly accurate and efficient method for blood lead analysis (BLA) through the use of a disposable electrode. A new type of mercury-plated preanodized screen-printed carbon electrode, together with a thallium(III) internal standard, simplifies calibration and gives easily quantifiable signals for accurate BLA. A preanodization procedure improves the preconcentration ability of the working electrode through the effect of lead (Pb) complexing with an electrogenerated surface functional group, mainly >C=O. Under optimized conditions, the ratio of the anodic stripping peak currents of Pb and Tl (i.e., i(Pb)/i(Tl)) is linear against [Pb] in the window of 1-300 ppb with a correlation coefficient and detection limit (signal-to-noise ratio=3) of 0.999 and 0.23 ppb, respectively. This approach was used to analyze blood samples (n=55) from workers at a local battery factory. The results are consistent with those obtained from graphite furnace atomic absorption spectroscopy and confirm the applicability of the proposed method.
Collapse
|
94
|
Ke JH, Kumar AS, Sue JW, Venkatesan S, Zen JM. Catalysis and characterization of a rugged lead ruthenate pyrochlore membrane catalyst. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/j.molcata.2005.02.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
|
95
|
Shih Y, Zen JM, Senthil Kumar A, Huang YN. Arbutin Flow-Injection Analysis Using a Printed Circuit-Board Waste Modified Screen-Printed Electrode. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2005. [DOI: 10.1246/bcsj.78.864] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
96
|
|
97
|
Kumar AS, Zen JM. Unusual Redox Catalysis in a Ruthenium Oxide–Prussian Blue Combined Material. Chemphyschem 2004; 5:1227-31. [PMID: 15446747 DOI: 10.1002/cphc.200400068] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
98
|
Shih Y, Zen JM, Senthil Kumar A, Lee YC, Huang HR. Determination of the Toxic Lead Level in Cosmetic-Hair Dye Formulations Using a Screen-Printed Silver Electrode. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2004. [DOI: 10.1246/bcsj.77.311] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
99
|
Zen JM, Hsu CT, Senthil Kumar A, Lyuu HJ, Lin KY. Amino acid analysis using disposable copper nanoparticle plated electrodes. Analyst 2004; 129:841-5. [PMID: 15343400 DOI: 10.1039/b401573h] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A disposable copper nanoparticle-plated screen-printed carbon electrode (designated as Cun-SPE(100-nm)) provides a new material for the determination of native amino acids. All 20 underivatized amino acids can be sensitively determined at 0.0 V vs. Ag/AgCl in pH 8 phosphate buffer solution. The precisely controlled copper nanoparticles can boost up the CuIIO/CuI2O redox signal on the working surface without any prior pretreatment procedure. The formation of a reversible 1:1 CuIIO-amino acid complex on the Cun-SPE(100-nm) was proposed to play a key role in the reaction mechanism. Stable detection responses were obtained for all amino acids by flow injection analysis with detection limits (S/N = 3) that lie in the range of 24 nM-2.7 microM. Selected amino acids from six representative chemical natures were separated by HPLC and detected at the Cun-SPE(100-nm) with promising results.
Collapse
|
100
|
Zen JM, Chen PY, Kumar AS. Flow Injection Analysis of an Ultratrace Amount of Arsenite Using a Prussian Blue-Modified Screen-Printed Electrode. Anal Chem 2003; 75:6017-22. [PMID: 14588045 DOI: 10.1021/ac0301649] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report here a new electrochemical method for the selective detection of ultratrace amount of arsenite (AsO(2)(-), As(3+)) using a Prussian blue-modified screen-printed electrode (designated as PBSPE) by flow injection analysis (FIA) in 0.1 M, pH 4 KCl/HCl carrier solution. The Prussian yellow/Prussian blue redox couple of the PBSPE was found to mediate the As(3+) oxidation. Various factors influencing the determination of As(3+) were thoroughly investigated in this study. Under the optimized FIA conditions, a linear calibration plot in the range of 50 nM-300 microM with a detection limit (S/N = 3) of 25 nM (i.e., 64.9 pg in 20-microL loop) was observed at an operation potential of +0.6 V vs Ag/AgCl. The sensitivity was good enough to detect arsenite at levels lower than the current EPA standard. This modified electrode showed good resistance to interference from common ions, especially Cl(-), which is generally considered as a major interference in the determination of As(3+) by ICPMS. The practical utility of the PBSPE to detect As(3+) was demonstrated in "blackfoot" disease endemic village groundwater from the southwestern coast area of Taiwan (Pei-Men).
Collapse
|