排序方式: 共有17条查询结果,搜索用时 15 毫秒
1.
Ibrahim Isildak Murat Yolcu Omer Isildak Nadir Demirel Giray Topal Halil Hosgoren 《Mikrochimica acta》2004,144(1-3):177-181
Two diaza-crown ether compounds were synthesized and evaluated as Ag+-selective carriers in polyvinylchloride (PVC) membrane electrodes of solid-state type. The all-solid-state PVC membrane electrode based on N,N-Dibenzyl-dibenzo-diaza-18-crown-6 exhibited a super-Nernstian response (75±10mV per decade) over the concentration range of 1×10–1 to 7×10–6M of Ag+ ion and a detection limit of 3×10–6M, at a wide range of pH (pH 4–7). The response time of the electrode was fast (less than 10s), and it can be used for three months without any significant deviation in potential. The proposed all-solid-state PVC membrane electrodes revealed high selectivity toward Ag+ ion with respect to alkali, alkaline earth, heavy and transition metal ions. A flow-through cell of all-solid-state PVC membrane Ag+-selective electrode based on N,N-Dibenzyl-dibenzo-diaza-18-crown-6 has also been prepared and applied for flow-injection analysis of Ag+ ion in solution. 相似文献
2.
Yusuf Kurtulmus T. Tanyalçın Giray Bozkaya Ogˇuzhan Gündüz Ömür Çerçi Fatma Z. Kutay Biltan Ersöz 《Accreditation and quality assurance》2001,6(9-10):424-426
The aim of this study was to compare two immunoassay measurement methods, the ACS:180 Plus (Chiron Diagnostics) kit and the Immulite sPSA (DPC) kit. Method comparison analysis was performed according to EP9-A; approved guideline of NCCLS 51. Serum samples having a wide range of total prostate-specific antigen (PSA) concentrations were evaluated in split-sample analysis. F-test, t-test analysis and regression statistics were performed. In Deming regression analysis the coefficients were as follows; the slope=0.967; y-intercept=-0.148, r=0.989. An acceptable bias was seen since the systematical error was calculated to have a value less than the total allowable error calculated from biological variations. Non-parametric evaluation of the area under ROC curves for ACS:180 Plus and Immulite sPSA were 0.997 and 0.987, respectively. Diagnostic accuracy was at the level of p= 0.000 and no statistical difference was found between the two assay methods. 相似文献
3.
Didem Giray Dilgin Bensu Ertek Yusuf Dilgin 《Journal of the Iranian Chemical Society》2018,15(6):1355-1363
In this work, firstly methylene blue (MB) was electropolymerized onto pencil graphite electrode (PGE) surface for the electrocatalytic oxidation of NADH. Cyclic voltammograms show that oxidation potential of NADH at Poly-MB/PGE shifted to negative direction about 300 mV compared with bare PGE. These results indicate that Poly-MB/PGE exhibits a good electrocatalytic activity toward NADH oxidation. Then, a glucose biosensor study was performed based on the determination of enzymatically generated NADH by glucose dehydrogenase (GDH) which immobilized onto Poly-MB/PGE using glutaraldehyde cross-linking procedure. The biosensing of glucose in flow injection analysis (FIA) system was performed at GDH/Poly-MB/PGE for the first time. The electrocatalytic oxidation currents of enzymatically produced NADH obtained from FI amperometric current–time curves recorded at + 200 mV and in phosphate buffer solution at pH 7.0 containing 1.0 M KCl were linearly related to the concentration of glucose. Linear calibration plots are obtained in the concentration range from 0.01 to 1.0 mM. The limit of detection (LOD) was found to be 4.0 µM. A fast, sensitive, low-cost and disposable glucose biosensor was constructed in FIA system using GDH/Poly-MB/PGE; therefore, it might provide a new perspective for the fabrication of biosensor of other compounds such as glutamate, lactate and alcohol. 相似文献
4.
Teslime Erşan Didem Giray Dilgin Elif Kumrulu Umur Kumrulu Yusuf Dilgin 《Electroanalysis》2023,35(4):e202200295
This work describes the sensitive voltammetric determination of favipiravir (FAV) based on its reduction for the first time with a low-cost and disposable pencil graphite electrode (PGE). In addition, the determination of FAV was also performed based on its oxidation. Differential pulse (DP) voltammograms recorded in 0.5 M H2SO4 for the reduction of FAV show that peak currents increase linearly in the range of 1.0 to 600.0 μM with a limit of detection of 0.35 μM. The acceptable recovery values (98.9–106.0 %) obtained from a pharmaceutical tablet, real human urine, and artificial blood serum samples spiked with FAV confirm the high accuracy of the proposed method. 相似文献
5.
Measured (n = 36, 51 ·g/day) and estimated (n = 274, 44 ·g/day) dietary daily intake of selenium in Turkey is low compared to the RDA value of 55 ·g Se/day. When the existence
of high prevalence of iodine deficiency in most part of the country is considered, adequate level of dietary Se becomes more
important. We have found recently that high iodine-deficient goitrous children had lower Se levels and antioxidant enzyme
(AOE) activities, and higher levels of DNA base lesions than non-goitrous controls.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
6.
Mahmut Torul Halil Hogren Giray Topal Mürüvvet Yurdako 《Journal of heterocyclic chemistry》2005,42(6):1201-1205
A new selective molecular receptor, borocryptate, based on the combination of the 15 membered ring diazatrioxa core and two saligenin units as binding sites for boron has been described. The resulting peristatic chiral compound is stable in air and easily converted to polynuclear complex, Na‐borocryptate, without using an inert atmosphere. 相似文献
7.
A novel fiber optic spectrophotometric determination of nitrite using Safranin O and cloud point extraction 总被引:1,自引:0,他引:1
A novel fiber optic spectrophotometric method for nitrite determination in different samples is suggested, based on the reaction of nitrite with Safranin O in acidic medium to form a diazo-safranin, which is subsequently coupled with pyrogallol in alkaline medium to form a highly stable, red azo dye, followed by cloud point extraction (CPE) using a mixed micelle of a nonionic surfactant, Triton X-114, with an anionic surfactant, sodium dodecyl sulphate (SDS). The reaction and extraction conditions (e.g., acidity for diazotization and alkalinity for pyrogallol coupling, and other reagent concentrations, time, and tolerance to other ions) were optimized. Linearity was obeyed in a concentration range up to 230 μg L−1, and the detection limit of the method is 0.5 μg L−1 of nitrite ion. The molar absorptivity for nitrite of the Safranin-diazonium salt (?610 nm = 4 × 103 L mol−1 cm−1) existing in literature was greatly enhanced by pyrogallol coupling and CPE enrichment (?592 nm = 1.39 × 105 L mol−1 cm−1). The method was applied to the determination of nitrite in tap water, lake water and milk samples with an optimal preconcentration factor of 20. 相似文献
8.
Molecular Diversity - In this study, for the first time, lactic acid was used as a bio-based green catalyst and reaction medium for the synthesis of 1,2,3,4-tetrasubstituted pyrrole derivatives... 相似文献
9.
Didem Giray Dilgin Delia Gligor H. İsmet Gökçel Zekerya Dursun Yusuf Dilgin 《Mikrochimica acta》2011,173(3-4):469-476
A new approach is described for the photoelectrocatalytic oxidation of Reduced ß-Nicotinamide Adenine Dinucleotide (NADH). It is based on a glassy carbon electrode (GCE) modified with a film of poly-Neutral Red (poly-NR) that is obtained by electropolymerization. Electrochemical measurements revealed that the modified electrode displays electrocatalytic and photo-electrocatalytic activity towards oxidation of NADH. If irradiated with a 250-W halogen lamp, the electrode yields a strongly increased electrocatalytic current compared to the current without irradiation. Amperometric and photo-amperometric detection of NADH was performed at +150 mV vs. Ag/AgCl/KClsat and the currents obtained are linearly related to the concentration of NADH. Linear calibration plots are obtained in the concentration range from 1.0 μM to 1.0 mM for both methods. However, the slope of the current-NADH concentration curve of the photo-electrocatalytic procedure was 2-times better than that obtained without irradiation. Figure
A poly-Neutral Red modified glassy carbon electrode (poly-NR/GCE) was prepared by electropolymerization process. This modified electrode displays electrocatalytic and also photoelectrocatalytic activity towards oxidation of NADH. Compared with electrocatalytic oxidation of NADH, the current response was increased about 2.0 times in the photoelectrocatalytic oxidation process. 相似文献
10.
Quasi-Monte Carlo simulation is a popular numerical method in applications, in particular, economics and finance. Since the normal distribution occurs frequently in economic and financial modeling, one often needs a method to transform low-discrepancy sequences from the uniform distribution to the normal distribution. Two well known methods used with pseudorandom numbers are the Box–Muller and the inverse transformation methods. Some researchers and financial engineers have claimed that it is incorrect to use the Box–Muller method with low-discrepancy sequences, and instead, the inverse transformation method should be used. In this paper we prove that the Box–Muller method can be used with low-discrepancy sequences, and discuss when its use could actually be advantageous. We also present numerical results that compare Box–Muller and inverse transformation methods. 相似文献