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اطلاعات دوره: 
  • سال: 

    2013
  • دوره: 

    9
تعامل: 
  • بازدید: 

    133
  • دانلود: 

    0
چکیده: 

EPINEPHRIN (EP) IS AN IMPORTANT NEURO TRANS MITTERS IN MAMMALIAN CENTRAL NERVOUS SYSTEMS (1), AND IT EXITS IN THE NERVOUS TISSUE AND BODY FLUID IN THE FORM OF LARGE ORGANIC CATIONS. THE CHANGE OF ITS CONCENTRATION MAY RESULT IN MANY DISEASES (2). THERE ARE SOME METHODS APPLIED FOR THE DETERMINATION OF EP. AS AN ELECTROACTIVE DEVICE, IT CAN ALSO BE STUDIED VIAELECTROCHEMICAL TECHNIQUE. SOME REPORTS SHOWED THE ELECTROCHEMICAL RESPONSE OF EP ON DIFFERENT KINDS OF ELECTRODES .NANO COMPOSITE ZEFE2O4/TIO2 MODIFIED CARBON PASTE ELECTRODE HAS BEEN USED FOR THE DETERMINATION OF EPINEPHRIN (EP) BY CYCLIC VOLTAMMETRY (CV). DIFFERENTIAL PULSE VOLTAMMETRY (DPV). BASIED ON THE ANODIC OXIDATION PEAK AT (0.6 V) IN H3PO4 (0.1M) BUFFER AT (PH: 7). A LINEAR AN ANALYTICAL CURVE WAS ABSERVED IN THE RANGE OF 0.08 M M TO260 M M (R2:0.998). THE DETERMINATION LIMIT FOR THIS METHOD IS 0.07 M M. WE EXAMINED THIS METHOD FOR THE VOLTAMMETRIC DETERMINATION OF EP IN INJECTION SAMPLES.

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اطلاعات دوره: 
  • سال: 

    2018
  • دوره: 

    10
  • شماره: 

    12
  • صفحات: 

    1538-1547
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    328
  • دانلود: 

    0
چکیده: 

Pb2+ ion was investigated by voltammetry selectivity using TiO2-Ionophores hexa(p-tert butyl)hexa(ethyl ester)calix[6]arene (BEK6) composite to increase the selectivity and sensitivity of carbon paste electrode (CPE). The BEK6 was synthesized by using hydrolysis method, meanwhile the TiO2-P25 and graphite powder were mixed as an electrode composite. The Scanning Electron Microscopy (SEM) shows that the CPE doped TiO2-BEK6 (CPE/TiO2-BEK6) have morphology likes a rough, non-porous, composed of fine particles, and homogeneously. The presence of Pb2+ ion in pH 5 citrate buffer electrolyte causes the peaks appearance on Epa and Epc were 0. 17 V and 0. 37 V with the peak potential current generated of 15. 15 μ A and-12. 0 μ A, respectively. The 0. 005 g BEK6 was increased significantly the peak current of the Pb2+ ion with the LOD value of 0. 1756. In addition, the presence of TiO2-BEK6 composite shows the measurement current stability by %RSD of 0. 83.

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بازدید 328

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نویسنده: 

JOZ YARMOHAMMADI F. | ZAMANI H.A.

اطلاعات دوره: 
  • سال: 

    2014
  • دوره: 

    20
تعامل: 
  • بازدید: 

    147
  • دانلود: 

    0
چکیده: 

A MODIFIED NANO-COMPOSITE CARBON PASTE ELECTRODE FOR LU3+IONS WAS PREPARED BY EMPLOYING 2, 2’ -DITHIOBIS (4-METHYLTHIAZOLE) AS AN IONOPHORE AND PARAFFIN OIL AS A BINDER. NANO-COMPOSITE CARBON PASTE ELECTRODE WAS MODIFIED BY MULTI-WALLED CARBON NANO-TUBE (MWCNTS) AND NANOSILICA TO IMPROVEMENT IN THEIR CHARACTERIZATIONS SUCH AS SENSITIVITY AND SELECTIVITY, ESPECIALLY IN TERM OF RESPONSE TIME, RESPONSE STABILITY AND LIFETIME IN COMPARISON WITH TYPICAL CARBON PASTE ELECTRODE [1]. THE BEST PERFORMANCE FOR NANO-COMPOSITE SENSOR WAS OBTAINED WITH ELECTRODE COMPOSITION OF 25% PARAFFIN OIL, 3% TMT, 3% MWCNTS, 0.5% NANO-SILICA AND 40% GRAPHITE.THE SENSORS EXHIBITS NERNSTIAN RESPONSE FOR THE LU3+IONS OVER THE CONCENTRATION RANGE 5.0×10-8-1.0×10-2 M AT PH 2.8-9.3 WITH A LOWER DETECTION LIMIT OF 2.5×10-8 M AND THE SLOPE OF 19.9 ± 0.3 MV PER DECADE. THE RESPONSE TIME WAS RELATIVELY QUICK IN THE WHOLE CONCENTRATION RANGE (~5 S).IN THIS RESEARCH, POTENTIOMETRIC SELECTIVITY COEFFICIENTS, DESCRIBING THE PREFERENCE OF THE ELECTRODE FOR LUTETIUM IONS RELATIVE TO AN INTERFERING ION, WERE DETERMINED BY THE MATCHED POTENTIAL METHOD (MPM) [2]. THE SENSOR REVEALED HIGH SELECTIVITY WITH RESPECT TO ALL COMMON ALKALI, ALKALINE EARTH, TRANSITION AND HEAVY METAL IONS, INCLUDING MEMBERS OF THE LANTHANIDE FAMILY OTHER THAN LU3+. THE LU3+SENSOR WAS SUCCESSFULLY APPLIED AS AN INDICATOR ELECTRODE IN THE POTENTIOMETRIC TITRATION OF LU (III) IONS WITH EDTA [3].

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نویسنده: 

JOZ YARMOHAMMADI F. | ZAMANI H.A.

اطلاعات دوره: 
  • سال: 

    2013
  • دوره: 

    9
تعامل: 
  • بازدید: 

    114
  • دانلود: 

    0
چکیده: 

PLEASE CLICK ON PDF TO VIEW THE ABSTRACT.

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بازدید 114

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اطلاعات دوره: 
  • سال: 

    2014
  • دوره: 

    11
تعامل: 
  • بازدید: 

    157
  • دانلود: 

    0
چکیده: 

IMBALANCE OF BLOOD SUGAR IS A GLOBAL HEALTH CARE PROBLEM THAT TREATABLE DISEASE AFFECTING ABOUT 200 MILLION PEOPLE AROUND THE WORLD [1]. ALTHOUGH THERE ARE MANY DIFFERENT METHODS FOR GLUCOSE DETERMINATION, BUT ELECTROCHEMICAL METHODS HAVE ABSORPTION MORE CONCENTRATION DUE TO THEIR SIMPLICITY, PROPER SELECTIVITY AND HIGH SENSITIVITY [2]. IN THIS STUDY, SENSITIVE AND STABLE NON-ENZYMATIC GLUCOSE SENSOR BASED ON GO/NC/CUO COMPOSITE PASTE ELECTRODE WAS FABRICATED. THE MORPHOLOGY OF NANOMATERIAL AND NANOCOMPOSIT WERE INVESTIGATED BY SCANNING ELECTRON MICROSCOPY (SEM), TRANSMISSION ELECTRON MICROSCOPY (TEM) AND XRAY DIFFRACTION(XRD).CYCLIC VOLTAMMETRY AND AMPEROMETRY WERE PERFORMED TO STUDY THE ELECTROCATALYTIC OXIDATION OF GLUCOSE IN ALKALINE MEDIUM AT GO/NC/CUO-CPE. A LINER RANG OF 0.05 TO 30 MM GLUCOSE, LIMIT OF DETECTION 2.5MM (SIGNAL-TO-NOISE 3) WERE OBSERVED. THE MODIFIED ELECTRODES OFFER EXCELLENT ELECTRO CATALYTIC ACTIVITY TOWARD THE GLUCOSE OXIDATION AT LOW POSITIVE POTENTIAL (0.4 V VS AG/AGCL). AS A RESULT, IT COULD BE CONCLUDED THAT GO/NC/CUO-CPE AT PRESENCE OF NC WOULD PAVE THE WAY FOR GLUCOSE BIOSENSOR. THE NOVEL GLUCOSE SENSOR ALSO EXHIBITS GOOD REPRODUCIBILITY, LONG-TERM STABILITY, AS WELL AS NO INTERFERENCE FROM L-ASCORBIC ACID, URIC ACID, FRUCTOSE AND GALACTUS, SO IT IS REASONABLE TO EXPECT ITS BROAD USE IN NON-ENZYMATIC GLUCOSE SENSOR.

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اطلاعات دوره: 
  • سال: 

    2013
  • دوره: 

    16
تعامل: 
  • بازدید: 

    122
  • دانلود: 

    0
کلیدواژه: 
چکیده: 

FUEL CELLS ARE BEING CONSIDERED AS AN IMPORTANT TECHNOLOGY THAT CAN BE USED FOR VARIOUS POWER APPLICATIONS. THEY ARE DEVICES IN WHICH THE ENERGY OF A CHEMICAL REACTION IS CONVERTED DIRECTLY INTO ELECTRICITY. IN DIRECT METHANOL FUEL CELLS (DMFCS), METHANOL IS USED AS A FUEL [1].UNFORTUNATELY, COMPOUNDS SUCH AS METHANOL WITH LARGE OXIDATION OVER POTENTIAL AT ORDINARY CARBON ELECTRODES ARE NOT SUITABLE ANALYTES FOR THESE ELECTRODES. ONE PROMISING APPROACH FOR MINIMIZING OVERVOLTAGE EFFECTS IS IN CARRYING OUT THE ELECTRO CATALYTIC PROCESS AT CHEMICALLY MODIFIED ELECTRODES [2, 3].THE ELECTROCHEMICAL BEHAVIOR OF METHANOL AT THE SURFACE OF A CARBON-PASTE ELECTRODE (CPE) MODIFIED WITH POLY (P-PHENYLENDIAMIN/POSS) NANO COMPOSITE IS DESCRIBED. THE STRUCTURE OF THE NANO COMPOSITE WAS CHARACTERIZED BY FT-IR SPECTROSCOPY. CATALYTIC ACTIVITY AND STABILITY FOR THE OXIDATION OF METHANOL WERE STUDIED BY USING CYCLIC VOLTAMMETRY. THE RESULTS SHOW THAT THE NANO COMPOSITE SIGNIFICANTLY ENHANCES THE EFFECTIVE SURFACE AREA AND THE CATALYTIC ACTIVITY OF THE CPE FOR OXIDATION OF METHANOL. THE RESULTS OBTAINED CONFIRMED THAT THE DISPERSION OF THE POSS PARTICLES IS CONNECTED WITH CATALYTIC RESPONSE TO A HIGHER ACTIVITY. THE NANO TUBULAR MORPHOLOGY OF POLY (P-PHENYLENDIAMINE) HELPS IN THE EFFECTIVE DISPERSION OF POSS PARTICLES FACILITATING THE EASIER ACCESS OF METHANOL TO THE CATALYTIC SITES. THE POLY (P-PHENYLENDIAMINE) NANOTUBES MODIFIED WITH POSS NANOPARTICLES CAUSE A GREAT INCREASE IN ELECTRO ACTIVITY AND THE ELECTRO-CATALYTIC PROPERTIES OF CPE FOR METHANOL.

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بازدید 122

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نویسنده: 

SADEGHI MAHSA | Zamani Hassan Ali

اطلاعات دوره: 
  • سال: 

    2015
  • دوره: 

    11
تعامل: 
  • بازدید: 

    120
  • دانلود: 

    0
چکیده: 

POTENTIOMETRIC SENSORS HAVE SHOWN TO BE VERY EFFECTIVE TOOLS FOR ANALYSIS OF A WIDE VARIETY OF METAL IONS. AMONG THEM, CARBON PASTE ELECTRODS (CPES) HAVE ATTRACTED INTEREST AS A RESULT OF THEIR IMPROVED RENEWABILITY, STABLE RESPONSE, AND LOW OHMIC RESISTANCE COMPARED TO MEMBRANE ELECTRODES.N, N′-DIPYRIDOXYL (1, 3-PROPANEDIAMINE) (PYPA) SEEMED TO BE A SUITABLE ION CARRIER FOR METAL IONS DUE TO THE PRESENCE OF HARD DONATING O AND INTERMEDIATE DONATING N ATOMS AND EVEN THE EXISTENCE OF ELECTRON RICH DOUBLE BOUND IN ITS STRUCTURE. PRELIMINARY SOLUTION STUDY SHOWS THE SELECTIVITY OF (PYPA) TOWARD CR (III) IONS IN COMPARISON OF OTHER COMMON CATIONS, INCLUDING ALKALI, ALKALINE EARTH, TRANSITION AND HEAVY METAL IONS. TO HAVE A LONG-TERM STABLE ELECTRODE FOR POTENTIOMETRIC USES, (PYPA) WAS APPLIED AS IONOPHORE IN PREPARATION OF ANANO-COMPOSITE CARBON PASTE ELECTRODE.

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بازدید 120

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اطلاعات دوره: 
  • سال: 

    2021
  • دوره: 

    8
  • شماره: 

    3
  • صفحات: 

    261-274
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    34
  • دانلود: 

    0
چکیده: 

In the present work, a combination of unique properties of two nanomaterial compounds, MgO nanoparticles (MgO NPs) and multiwall carbon nanotubes (MWCNT), and electrocatalytic activity of an oxadiazole derivative, 3-(5-(pyridine-4-yl)-1, 3, 4-oxadiazole-2-ylthio)-4-methylcyclohexa-1, 3-diene-1, 2-diol,POM, was used to fabricate a sensitive electrode (POM-MgO NPs-MWCNT-CPE) for electrochemical determination of folic acid. The electrochemical treatment of folic acid was studied in phosphate buffer solution (0. 1 M, pH 7) by means of common electrochemical techniques such as cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The sensitive fabricated electrode displayed good operating characteristics such as a wide linear range, 0. 08-650. 0 μ, M, and low detection limit, 0. 02 μ, M, for the determination of folic acid. Using the modified electrode, the two well distinguished peaks were recorded at 110. 0 and 209 mV for ascorbic acid and folic acid, respectively. The reliability and accuracy of the introduced electrode were studied in pharmaceutical and biological samples.

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اطلاعات دوره: 
  • سال: 

    1403
  • دوره: 

    19
  • شماره: 

    70
  • صفحات: 

    293-312
تعامل: 
  • استنادات: 

    0
  • بازدید: 

    80
  • دانلود: 

    99
چکیده: 

در این کار تحقیقاتی، یک حسگر الکتروشیمیایی ساده و گزینش پذیر با حساسیت بالا برای تعیین داروی دوپامین پیشنهاد شد. برای این منظور، از یک نانوکامپوزیت متشکل از نیکل- نانولوله های کربنی چند جداره و نانوذرات تیتانیوم دی اکساید برای اصلاح الکترود خمیرکربن استفاده شد. مورفولوژی سطح حسگر اصلاح شده توسط میکروسکوپ الکترونی روبشی گسیل میدانی (FESEM) و طیف سنجی مادون قرمز تبدیل فوریه (FTIR) ارزیابی شد. روش های ولتامتری چرخه ای (CV)، ولتامتری پالس تفاضلی (DPV) و طیف سنجی امپدانس الکتروشیمیایی (EIS) برای تجزیه و تحلیل رفتار الکتروشیمیایی الکترود اصلاح شده پیشنهادی و تعیین خصوصیات الکتروشیمیایی دوپامین به کار رفتند. الکترود اصلاح شده به کاررفته در این پژوهش یک پاسخ الکترواکسیداسیون عالی به حضور دوپامین نشان داد. علاوه بر این، برای بهینه سازی پاسخ حسگر الکتروشیمیایی، هر گونه تغییر در رفتار ولتامتری دوپامین تحت شرایط pH و سرعت های روبش مختلف مورد بررسی قرار گرفت. تحت شرایط بهینه، جریان پیک الکتروکاتالیستی دوپامین، به غلظت دوپامین در محدوده µM 100- 3/0 به صورت خطی وابسته بوده و حد تشخیص nM 68/11 برای آن محاسبه شد. همچنین، پارامترهای الکتروشیمیایی مانند تعداد الکترون های منتقل شده و ضریب انتقال الکترون نیز برآورد شدند. یافته های مطالعه حاضر نشان دادند که حسگر موردنظر دارای حساسیت بالا، حد تشخیص کم، پاسخ سریع، پایداری طولانی مدت، قابلیت تکرارپذیری و تجدیدپذیری قابل توجه، گزینش پذیری و بازیابی بالا و همچنین، عملکرد عالی در تشخیص آنالیت در نمونه های حقیقی است که ثابت می کند الکترود پیشنهادی، برای کاربردهای صنایع غذایی، پزشکی و زیست محیطی کاملاً قابل استفاده می باشد. روش پیشنهادی ساده، سریع و ارزان است و می تواند به عنوان یک ابزار تحلیلی ارزشمند در کنترل کیفیت صنعت داروسازی مورد استفاده قرار گیرد.

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اطلاعات دوره: 
  • سال: 

    2013
  • دوره: 

    9
تعامل: 
  • بازدید: 

    125
  • دانلود: 

    0
چکیده: 

ACETAMINOPHEN (AC) OR PARACETAMOL, A WIDELY USED ANTIPYRETIC AND ANALGESIC DRUG, IS AN EFFECTIVE AND SAFE AGENT USED WORLD WIDE FOR THE RELIEF OF MILD TO MODERATE PAIN ASSOCIATED WITH HEADACHES, BACK ACHES, ARTHRITIS AND POSTOPERATIVE PAIN. IT IS USED FOR REDUCTION OF FEUERS OF BACTERIAL OR VIRAL ORIGIN [1]. NANO COMPOSITE OF ZNFE2O4 AND TIO2 MODIFIED CARBON PASTE ELECTRODE HAS BEEN USED FOR THE DETERMINATION OF ACETAMINOPHEN (AC), BY CYCLIC VOLTAMMETRY (CV), DIFFERENTIAL PULSE VOLTAMMETRY (DPV). THE RESULTS REVEALED THAT THE MODIFIED ELECTRODE SHOWS AN ELECTRO CATALYTIC ACTIVITY TOWARD THE ANODIC OXIDATION OF ACETAMINOPHEN IN THE CURRENT RESPONSE IN BUFFERED SOLUTION AT (PH: 4.2) AND THE ANODIC PEAK POTENTIAL SHIFTS BY 0.57V WHEN COMPARED WITH THE POTENTIAL USING BARE CARBON PASTE ELECTRODE. A LINEAR ANALYTICAL CURVE WAS OBSERVED IN THE RANGE OF 0.02 MM TO 120ΜM [R2:996]. THE DETECTION LIMIT FOR THIS METHOD IS 0.01MM. THE METHOD WAS THEN SUCCESSFULLY APPLIED TO THE DETERMINATION OF ACETAMINOPHEN IN TABLETS AND HUMAN URINE.

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