共查询到20条相似文献,搜索用时 15 毫秒
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Zhu X Zhang Y 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2008,70(3):510-513
Trace iodide was determined by inhibition kinetic method, which based on its inhibition effects on the reaction between rhodamine B (RhB) and KBrO(3) in H(2)SO(4) medium in 45+/-0.5 degrees C for 15 min. The signal difference (DeltaA, DeltaF) between inhibited reaction and non-inhibited reaction is linear with the concentration of iodide. The linear range were 2.0-6.0 and 1.0-6.0 ng mL(-1) and the detection limit were 0.06 and 0.07 ng mL(-1), respectively. The method has been applied satisfactorily to the determination of iodide in kelp. 相似文献
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Kinetic spectrophotometric method for rapid determination of trace formaldehyde in foods 总被引:1,自引:0,他引:1
A simple and sensitive kinetic-spectrophotometric method was developed for the determination of ultra trace amount of formaldehyde in food samples. The method was based on the oxidation of rhodamine B (RhB) by potassium bromate in sulfuric acid medium (formaldehyde as catalyst). The reaction was monitored by measuring the decrease in absorbance of the dye at 515 nm after 6 min. The developed method allowed the determination of formaldehyde in the range of 10–100 μg L−1 with good precision, accuracy and the detection limit was down to 2.90 μg L−1. The relative standard deviations for the determination of 10 and 60 μg L−1 of formaldehyde were 3.0% and 1.9% (n = 10), respectively. The method was found to be sensitive, selective and was applied to the determination of formaldehyde in foods with satisfactory results. 相似文献
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研究了钌(Ⅲ)催化高碘酸钾氧化固绿FCF褪色反应的反应条件, 测定了该反应的反应级数和表观活化能, 并建立了测定钌的新动力学光度法. 在选定实验条件下, 非催化反应体系与催化反应体系在633 nm波长处的吸光度差值与钌(Ⅲ)的质量浓度在0~0.001 μg/mL及0.001~0.0025 μg/mL范围内有良好的线性关系, 检出限为 9.53×10-11 g/mL. 对0.001 μg/mL钌(Ⅲ)测定11次标准偏差为1.7%, 方法的选择性好, 灵敏度高, 可用于钌精矿及合成样中痕量钌的测定. 相似文献
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Maryam Ganjikhah Shahab Shariati Elahe Bozorgzadeh 《Journal of the Iranian Chemical Society》2017,14(4):763-769
Formaldehyde is known as a highly toxic compound to humans and identified as a carcinogenic substance. In this study, Hantzsch reaction was utilized for the derivatization of trace amounts of formaldehyde in aqueous samples with acetylacetone in the presence of ammonia to form an extractable colored product named 3,5-diacetyl 1,4-dihydrolutidine (DDL) and its further extraction using two-phase hollow fiber liquid-phase microextraction. The main experimental variables affecting the extraction performance were investigated and optimized. Under the optimum conditions (sample volume 12 mL; reaction temperature 70 °C; ammonium acetate buffer solution 4 mL 0.1 mol L?1; acetylacetone 5 mL 0.15 mol L?1; solvent octanol, salt concentration 20% (w/v) NaCl; pH of donor phase 7.0; stirring speed 400 rpm and extraction time 30 min), the linear dynamic range, limit of detection (LOD as 3S b/m) and relative standard deviation (RSD %) of the proposed method were obtained as 5–250 μg L?1 (r 2 = 0.9979), 3.6 μg L?1 and 2.5%, respectively. Finally, the applicability of the proposed method was examined, and very good results were obtained. The results confirmed the applicability of the proposed method as a versatile, low-cost and sensitive preconcentration method for determination of low concentrations of formaldehyde in aqueous solutions. 相似文献
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Based on a property that in dilute hydrochloric acid hydrogen peroxide oxidizes Ponceau S to fade and cerium(IV) has a catalytic effect on the reaction, a new spectrophotometric method was developed for the determination of trace cerium(IV). At 450 nm, the cerium(IV) concentration presents a good linear relationship over the range of 0.08?4 μg/mL with the fading degree ΔA. Its linear regression equation is ΔA = 0.0475c (μg/mL) + 0.0007, with a correlation coefficient of 0.9991. The detection limit of method is 0.05 μg/mL. The method has been successfully applied to the determination of cerium in water and molecular sieve samples with good results. The relative standard deviations of eleven determinations were 0.97?1.11 and 0.19?1.01%, respectively. The recoveries of standard additions were 99.4?99.9 and 99.2?101.0%, respectively. The reliability of this method was certified by parallel determination against the dibromo-p-chlorochlorophosphonazo spectrophotometry. 相似文献
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Carbon disulfide (CS2) was determined at trace levels by its induction effect on the reaction of triiodide with azide in acidic media. The reaction was monitored spectrophotometrically by the decreased absorbance of triiodide over a period of 30 - 180 s from the initiation of the reaction at 350 nm, with calibration linear range of 0.020 - 1.870 microg/ml CS2. The limit of detection is 0.013 microg/ml CS2. A carbon-active column was used for sample solution clean up. The proposed method was successfully applied to the determination of trace carbon disulfide in natural water. 相似文献
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A new spectrophotometric method for the determination of formaldehyde is described, based on a colour reaction with oxalyidihydrazide and copper(II). The optimum reaction conditions, and other analytical parameters such as interferences, Beer's law, sensitivity, collection efficiency, etc. have been studied. 相似文献
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A method for the extraction-spectrophotometric determination of palladium with 2,2′-dithiodianilline (DTDA) is described. DTDA–Pd(II) complex is extracted from an aqueous solution with pH 3 into isobutyl methyl ketone (IBMK) layer. The absorbance is measured at 397 nm and the molar absorptivity found to be 1.47×106 l mol−1 cm−1. The complex system conforms to Beer's law over the range 0.3–220 ng ml−1 palladium (II). The effect of pH (1–6), NaClO4 concentration, DTDA concentration and shaking time were studied. The ratio of the metal ion to ligand molecules in the complex and its stability constant were found to be 1:1 and 1.45×106, respectively. The tolerance limit for many cations and anions have been determined. Finally the method has been applied successfully to the determination of palladium in synthetic mixtures, alloy and catalyst samples. 相似文献
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Kamal A. Idriss Magda S. Saleh Mohamed M. Seleim Fatma S. Hassan Sherif K. Idriss 《Monatshefte für Chemie / Chemical Monthly》1990,121(8-9):625-634
Summary A simple, rapid, selective, and sensitive method for the spectrophotometric determination of palladium is developed based on the reaction of Pd(II) with 1-amino-4-hydroxyanthraquinone (AMHA). The reaction is carried out atpH 3.8 in 50% (v/v) ethanol-water medium. The molar absorptivity of the complexed ligand is 1.1 · 104 l mol–1 cm–1 at 620 nm. Calibration plots are linear up to 17 µg Pd cm–3. The optimum concentration range (Ringbom plot) is between 3–14.5 µg cm–3. The spectral study of the reaction in solutions containing equimolar concentrations or an excess of one component, in thepH range 0.3–6.5, indicate the possible complex transitions that occur in solution. Complete graphical and logarithmic analysis of the absorbance-pH graphs was performed to demonstrate and characterize the complexation equilibria in solution. Under the optimum conditions, palladium can be determined as the noncharged complex Pd(AMHA)2 in the presence of a large number of foreign ions. Interferences caused by zirconium(IV) could be masked with fluoride ions.
Eine neue spektrophotometrische Methode für die Bestimmung von Palladium in Spuren
Zusammenfassung Eine einfache, schnelle und empfindliche Methode für die spektrophotometrische Bestimmung von Palladium wurde auf der Basis der Reaktion von Pd(II) mit 1-Amino-4-hydroxyanthrachinon (AMHA) entwickelt. Die Reaktion wird in 50% (v/v) Ethanol/Wasser beipH 3.8 ausgeführt. Die molare Absorption des komplexierten Liganden beträgt 1.1 · 104 l mol–1 cm–1 bei 620 nm. Kalibrierungskurven verlaufen bis zu 17 µg Pd cm–3 linear. Der optimale Konzentrationsbereich (Ringbom-Plot) liegt zwischen 3 und 14.5 µg cm–3. Spektroskopische Untersuchungen der Reaktion in Lösungen, entweder mit equimolaren Konzentrationen oder mit einem Überschuß an einer Komponente impH-Bereich 0.3–6.5, lassen Rückschlüsse auf mögliche Komplex-Übergänge in Lösung zu. Es wurde eine vollständige graphische, logarithmische Analyse der Absorptions-pH-Graphen durchgeführt, um die Komplexgleichgewichte in Lösung aufzuklären und zu charakterisieren. Unter den Optimalbedingungen kann Palladium als nichtgeladener Komplex Pd(AMHA)2 in Gegenwart einer großen Anzahl an Fremd-Ionen bestimmt werden. Schwierigkeiten mit Zirkonium(IV) konnte durch Maskierung mit Fluorid-Ionen umgangen werden.相似文献
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催化动力学分光光度法测定钢样中痕量铜 总被引:5,自引:0,他引:5
研究了在HAc NaAc缓冲体系的存在下,Cu(Ⅱ)催化H2O2氧化偶氮胂Ⅲ褪色反应,确定了最佳反应条件,建立了动力学光度法测定痕量铜Ⅱ的新方法。方法线性范围为0~0.2μg mL,检出限为2.1×10-3μg mL,用在测定钢样中的痕量铜可以不加掩蔽剂掩蔽干扰离子,而直接通过调节溶液的pH即可将干扰离子Fe3 沉淀除去,省去了掩蔽干扰离子的烦琐操作。 相似文献
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考马斯亮蓝G是一种生物染色剂 ,在分析测定中多用于蛋白质的测定[1 ,2 ] 。近年也有人用此试剂做催化动力学分析中的指示剂[3 ,4] 。我们在研究中发现 ,考马斯亮蓝G用于缔合物体系测定阳离子 ,有较好的结果。本文研究了以铜离子为催化剂 ,在抗坏血酸存在下的钼 硫氰酸盐 考马斯亮蓝显色体系 ,建立了一个灵敏的测定钼的方法。该方法灵敏度高 ,其表观摩尔吸光系数ε50 0 =2 .3 1×1 0 5L·mol- 1 ·cm- 1 。线性范围宽 ,钼的浓度在 0~2 1 μg/2 5mL范围内符合比尔定律。选择性较高 ,显色时间短 ,适合于生产中使用。该方法可用于合… 相似文献
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基于在NH3-NH4Cl介质中, Br-对H2O2氧化孔雀石绿的褪色反应有催化作用的特性, 建立了高灵敏度测定痕量溴化物的催化动力学光度分析法新体系. 讨论了酸度、试剂用量、温度、干扰离子等因素的影响. 研究了反应的最佳条件, 测定了一些动力学参数, 非催化反应和催化反应的的表观活化能分别为为52.85和19.53 kJ/mol. 方法的线性范围为0.10~1.2 μg/mL Br-, 检出限为 0.081 μg/mL. 方法用于水样中溴化物的测定, 结果与国标分析法所得结果相吻合. 相似文献
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在1.0×10-4mol·L-1的H2SO4中,牛血红蛋白催化H2O2氧化苯甲酸生成羟基苯甲酸,羟基苯甲酸在碱性溶液中有强荧光,据此提出了一种测定痕量H2O2的方法。在激发波长295 nm与发射波长408 nm处,反应体系的荧光增加值ΔF与H2O2的浓度在7.880×10-8~1.182×10-4mol·L-1范围内存在良好的线性关系。线性回归方程为:ΔF=7.418×106c+9.742(c的单位为mol·L-1),相关系数r=0.9994。检出限为5.26×10-8mol·L-1。将方法用于雨水及消毒液中H2O2的测定,结果满意。 相似文献