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61.
Jadranka Vuković Shiro Matsuoka Kazuhisa Yoshimura Vladimir Grdinić Renata Jurišić Grubešić 《Mikrochimica acta》2007,159(3-4):277-285
A simple, sensitive and rapid solid-phase spectrophotometric procedure was developed for the determination of traces of phenol
with 4-aminoantipyrine as a reagent (AAP-SPS), and the optimal experimental conditions were established. This method was performed by sorption and direct absorbance measurements
of the product phenol-AAP sorbed on the anion-exchanger Dowex 1-X4 (0.2 g) at 495 nm (absorption maximum) and 700 nm (non-absorption wavelength). The
sensitivity offered by the AAP-SPS procedure was higher by a factor of 40 compared with the respective conventional spectrophotometric method. Metrological
characteristics were established using a prevalidation strategy. The AAP-SPS procedure is characterized by a linear calibration function in the working range of 0.05–0.50 μmol, low standard deviation
of procedure (±0.012), low limit of determination (0.021 μmol), and favorable random (±0.85 to ±11.27%) and systematic deviations
(−4.55 to +11.50%). Moreover, the accuracy of the system investigated by the recovery test is acceptable (99–102%). Favorable
working and performance characteristics make the new SPS method ideal for phenol monitoring in pharmaceutical preparations
as well as other matrices. 相似文献
62.
A. C. Bhasikuttan A. V. Sapre L. V. Shastri 《Journal of photochemistry and photobiology. A, Chemistry》1995,90(2-3):177-182
The reactions of two triphenyl methane (TPM) dyes—crystal violet (CV+) and malachite green (MG+)—with N3• and OH• radicals were studied by pulse radiolytic kinetic spectrophotometry. The rate constants for the reaction of the cationic dyes (D+) with N3• are (9.0±0.6)×109 and (3.0±0.2)×109 dm3 mol−1 s−1 respectively and those for the reaction with OH• are obtained as (8.0±0.6)×109 and (1.1±0.1)×109 dm3 mol−1 s−1 respectively. The transient spectra resulting from the oxidation of the dyes were characterized. The time-resolved spectra indicate that the reaction with OH• radicals initially generates an adduct which subsequently dissociates to form the radical dication D•2+. The D•2+ species decay by further reaction with the parent dye. 相似文献
63.
A sensitive and selective method is described for the determination of neodymium in mixed rare earths using fourth-derivative spectrophotometry. The method is based on the absorption spectra of 4f electron transitions of the complex of neodymium with methyl thymol blue and cetylpyridinium chloride. The influence of various instrumental parameters and reaction conditions for maximum colour development are investigated. The calibration curve is linear over the range 0–3.5 g ml–1 neodymium. The relative standard deviation for determination of 1.4 g ml–1 neodymium (n = 7) is 1.6%. The detection limit (signal-to-noise ratio = 3) is 0.2 g ml–1. 相似文献
64.
Jing XU Lan Hua ZHAO Xin Guo WU Hong Mei WANG Ru Xiu CAI College of Chemistry Molecular Science Wuhan University Wuhan Stuff of Chemistry Yunyang Medical College Shiyan College of Resources Environmental Science Wuhan University Wuhan 《中国化学快报》2006,17(7):949-952
Quantification of free radical formation is critical for evaluation and interpretation of many radical-mediated biological processes1-4. Numerous studies have been devoted to the determination of free radicals, but the most of the reports have been focuse… 相似文献
65.
催化褪色光度法测定微量锰(Ⅱ)的研究 总被引:6,自引:2,他引:6
本文研究在硫酸介质中,锰(Ⅱ)催化EDTA还原重铬酸银,而使之褪色的新指示反应。确定了催化褪色反应动力学条件,锰(Ⅱ)的浓度在0-0.4μg/ml范围内,工作曲线呈良好的线性关系,检测限为0.011μg/mL,该方法用于天然水及污水中锰的测定,获得满意结果。 相似文献
66.
提出了同时测定铜基合金中铝和铁的流动注射分析法。以0.04mol/LHCl作载液,铬天青S为显色剂,通过测定628nm处铝、铁两配合物的吸光度之和及铝配合物的吸光度,实现了两组分的同时测定。在优化的实验条件下,检测限:Al和Fe分别为1.69×10-3和1.73×10-3mg/L,Al浓度在0~0.8mg/L;Fe浓度在0~1.0mg/L时服从比耳定律。进样频率为60样/h,所拟方法用于实际样品分析,获得满意结果。 相似文献
67.
采用火焰原子吸收分光光度法测定5种英平诸痹灵药酒中钴、锶、锂的含量。结果表明,该类药酒中微量元素Sr含量较高,微量元素Co、Li含量较低,该结果为讨论抗类风湿药物中微量元素与治疗类风湿疾病的关系提供了有用数据。 相似文献
68.
A selective Spectrophotometric method has been developed for the trace determination of copper after adsorption of its 1-phenyl-4,4,6-trimethyl(1H, 4H)-pyrimidine-2-thiol (PTPT) complex onto microcrystalline naphthalene. The complex is quantitatively adsorbed on naphthalene in the pH range 7.5–11.5, separated by filtration, dissolved in dimethylformamide (DMF) and determined spectrophotometrically at 400 nm. Beer's law is obeyed in the concentration range 2.5–37.5 g of copper in 10 ml of DMF. The molar absorptivity and Sandell's sensitivity are 1.30 × 1041 · mol–1 · cm–1 and 0.0048g cm–2, respectively. Ten replicate analyses of a solution containing 20.0 g of copper gave a mean absorbance of 0.410 with a relative standard deviation of 0.91 %. The interferences of various ions have been studied and the method has been validated by the determination of copper in various standard reference materials, beers, wines, human hair, goat liver and environmental samples.On leave from St. Stephen's College, Delhi 110 007, India 相似文献
69.
A simple, sensitive and rapid derivative spectrophotometric method using 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) has been developed for simultaneous determination of Co(II), Ni(II) and Fe(II) which have very similar chemical behavior and appear together in many real samples. The complexes of all these metal ions with 5-Br-PADAP were formed immediately at pH 7.0 ammonium acetate buffered solution and were stable for at least 24 h. Second derivative spectra were selected for evaluation, because working wavelength determination was more precise and spectral overlap was less than in the ordinary and first derivative spectra. Three wavelengths at which the complexes exhibit extremum 2D values for Co(II), Ni(II) and Fe(II) were selected as analytical wavelengths, i.e., 640, 600 and 740 nm, respectively. Calibration curves drawn with zero-to-peak values at mentioned wavelengths were linear between 80 and 2000 ng ml−1 for each metal ion. Concentrations of Co(II) and Ni(II) were calculated from the total 2D values and the sum of the linear equations for these three cations at 640 and 600 nm, after Fe(II) assay by making use of the 2D value at 740 nm. Limits of detection (LOD) for Co(II), Ni(II) and Fe(II) were 2.7, 13.9 and 3.0 ng ml−1, respectively. The method has been applied to tool steel and heater resistance wire samples successfully. 相似文献
70.