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《Analytical letters》2012,45(9):1333-1345
Abstract An operationally inexpensive and satisfactory analytical procedure for sulfur dioxide is proposed. The reagent 3-methyl-1,2-cyclopentanodione dithiosemicarbazone has been used to determine trace amounts of sulfur dioxide indirectly using the reduction of Fe(III) to Fe(II) principle. In order to find the optimal conditions for SO2 determination, properties of 3-Me-CPDT-Fe(II) complex such as its composition, stability and free energy change of formation have been determined. The best conditions for the complex formation such as standing time, pH, wavelength and the effect of interfering ions are described. The complex has been used with success in spectrophotometric determination of SO2. The procedure can determine down to 0.63 μg and recoveries are better than 97.5%. The method is also suitable for determination of sulfur dioxide in the air provided that interfering gases such as H2S and NO2 are removed. 相似文献
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HCPCF is a color reagent for the determination of vanadium, zinc and magnesium, etc. To the best of our knowledge, no work on the decoloring reaction for analytical use of HCPCF for the determination of oxidative anions has been report. In this work, we found that some oxidative anions can oxidize HCPCF in acid medium, forming a colorless product. In addition, surfactant was used in this work, because of the low solubility of HCPCF in aqueous solutions. The purpose of this work is to establish a new, rapid and simple spectrophotometric method for the determination of NO2-, BrO3-,IO3-, IO4-and Cr2O7-based on the reaction between HCPCF and analytes in the presence of emulsion OP. 相似文献
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耐尔蓝-溴酸钾体系褪色光度法测定痕量甲醛 总被引:8,自引:0,他引:8
1 引 言近年来 ,随着一些以甲醛为生产原料的材料 (如酚醛树脂等 )广泛应用于室内装修、家具以及化纤地毯等消费品的生产 ,甲醛已成为重要的环境污染物之一。传统的甲醛测定方法主要有变色酸光度法和乙酰丙酮光度法 ,二者灵敏度不高。最近报道的测定甲醛的方法有色谱法、电化学方法、荧光法、化学发光等方法。而利用动力学光度法测定的报道较少。研究发现 ,痕量甲醛在硫酸介质中对溴酸钾 耐尔蓝 (NB)溶液具有加快其褪色的作用 ,从而提出一种高灵敏度的痕量甲醛的测定新方法。该方法的线性范围为 8~ 1 2 0 μg L;检出限为 5 μg L… 相似文献
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一种用于食品中二氧化硫快速测定的样品前处理方法 总被引:6,自引:0,他引:6
提出了一种采用半微量蒸馏-半导体制冷技术的食品中二氧化硫快速提取的新方法, 研制出了可在15 min内完成二氧化硫提取的食品检测快速蒸馏提取装置. 采用本装置, 无需冷凝水和含汞吸收剂即可实现对样品中二氧化硫的蒸馏提取. 考察了蒸馏液酸度、 蒸馏液体积、 馏分收集体积和蒸馏提取时间对二氧化硫提取效率的影响. 研究结果表明, 采用该方法在30 min内即可完成对食品中二氧化硫的快速定量测定. 相似文献
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废水中二氧化硫脲的分光光度法测定 总被引:2,自引:0,他引:2
本文提出了分光光度法测定二氧化硫脲的新方法。在pH11.3的碱性介质中,二氧化硫脲可将芳香族硝基化合物还原为芳香族伯胺,经重氮化后与萘乙二胺反应生成红色的偶氮染料。其最大吸收波长为525nm,线性范围为2.0 ̄40.0mg/L,检测限2mg/L,回收率97.0% ̄102.7%。本法灵敏度高,对二氧化硫脲有较好的选择性,用于为水中微量二氧化硫脲的测定,结果满意。 相似文献
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《Physics and Chemistry of Liquids》2012,50(1):81-85
A simple spectrophotometric technique is reported for the determination of propoxur using the coupling complexing agents namely 2-amino, 4-nitrophenol and 2,4-dimethoxy aniline. The u max observed for these coloured complexes were at 402 and 460 nm respectively. The recoveries of propoxur pesticides obtained using the above procedure were reported in their formulations, water and food grains. 相似文献
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《Analytical letters》2012,45(9):1917-1926
Abstract Azithromycin (AZT), an antibiotic belonging to the family of macrolides, can be analyzed by a new spectrophotometric method based on the formation of an ion pair between this drug and an inorganic complex of (Mo(V)–thiocyanate) followed by its extraction with dichloroethane. This ion‐association complex shows an orange color and exhibits a maximum absorbance at 469 nm. The experimental conditions of the reaction were studied and optimized. The calibration graph was linear (r=0.9996) over the range 10?6 M–10?5 M of AZT. This simple and validated method has been successfully applied to the determination of azithromycin in pharmaceutical formulations with a mean relative standard deviation of 1.07% and mean recovery of 99.66%. The common excipients present in azithromycin formulations did not interfere in its determination. This new spectophotometric method has been applied successfully to illustrate the dissolution profiles of original tablets and generic compounds; hence, it could be employed in routine quality control of azithromycin in pharmaceutical dosage forms. 相似文献
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《Analytical letters》2012,45(13):2601-2614
Abstract A highly selective spectrophotometric method for the determination of aqueous sulfite was developed. Sulfite was found to react with o-phthaldialdehyde in presence of ammonia yielding a deep blue colored complex the absorbance of which is sensitive to trace sulfite concentrations. The method is simple, very sensitive, and convenient for the determination of as little as 5X10?6 M sulfite. The molar absorptivity of the colored complex is about 1.2X104 L cm?1 mol?1. The proposed method is more sensitive and selective for sulfite than the widely used Ellman reagent method. Absorbance is measured at 628 nm which is the best of the two absorption maxima that are exhibited by the compound. 相似文献
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《Electroanalysis》2004,16(23):1944-1948
A series of cyclopentadienylnickelthiolate complexes, [Ni(PBu3)(η5‐C5H5)(SC6H4X‐4)] (X=F, Cl, Br, NH2), were shown to express stable reversible electrochemical properties even after formation of SO2 adducts in organic phase consisting of argon purged CH2Cl2/0.1 M [n‐Bu4N][BF4]. The formal potentials (E°′) values of the compounds ranged from 265 to 431 mV/Ag‐AgCl depending on the para substituent of the benzene thiolate ligand. Electrochemical, UV‐vis and 1H NMR spectroscopic analyses show that the formation of SO2 adducts causes the perturbation of the electronic density of the nickel metal center, indicated by shifts in the E°′ values of the NiII/III redox couple that is dependent on SO2 concentration. The detection limits of the resulting organic phase electrochemical gas sensor system was as low as 0.56 ppm SO2 for the fluoro complex, while the linear range was as high as 700–2000 ppm SO2 for the amino complex. 相似文献
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《Analytical letters》2012,45(5):959-963
Abstract A highly sensitive spectrophotometric method has been developed for the determination of nitrogen dioxide (nitrite as NOz ?) by reacting manganese dioxide in 1:20 perchloric acid. An amount of manganese dioxide (MnOz) equivalent to the concentration of nitrogen dioxide becomes soluble due to the reduction of Mn (IV) to Mn (II) by nitrite in acidic medium. The soluble Mn (II) ion is filtered to remove excess of MnO2 and is oxidized to permanganate ion by periodic acid in presence of phosphoric acid. The violet colored solution shows maximum absorbance at 525 nm. The sensitivity of the method is 0.08 ppm based on 0.0044 absorbance, and Beer's law is obeyed in the concentration range of 0.2 to 10.0 μg/mL of NO2 ?. Molar absorbance is found to be 2442 at 525 nm. In the present investigation NO2 ? was treated with excess of MnO2 in 1:20 perchloric acid where NO2 ? reduces equivalent amount of Mn (IV) to Mn (II) and becomes soluble. The soluble Mn (II) was heated to boiling and 25 mg (approx.) periodic acid is added and cooled. The volume of each solution is made to 50 mL in volumetric flask. Reagent blank is prepared in similar way except sodium nitrite solution. The absorbance is measured at 525 nm against reagent blank. 相似文献
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二氧化硫测定过程中烟气预处理器适用范围研究 总被引:1,自引:0,他引:1
建立了一种确定二氧化硫测定过程中烟气预处理器适用范围的方法。通过使用模拟烟气检测平台,分析了使用烟气预处理器条件下,湿度和二氧化硫设定浓度变化对二氧化硫浓度测定值及二氧化硫其损失的影响,确定了二氧化硫损失率小于5%时烟气预处理器的适用范围:二氧化硫含量大于91.9 mg/m3时,湿度不大于15.1%;二氧化硫含量在33.0~91.9 mg/m3之间时,湿度不大于10.4%。该方法有助于提高二氧化硫检测和排污总量核算的准确性。 相似文献
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本文建立了吗啡的流动注射分光光度分析法。在优化条件下,线性检测范围为30~700μg/ml,回归方程为h=0.0250+1.74×10~(-3)C,相关系数为0.9999,并用于吗啡样品的分析。回收率为99.9%,相对标准偏差为0.43%,样品分析速度为240次/小时。 相似文献
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《Analytical letters》2012,45(3):261-267
Abstract Cycloserine has been determined by a spectrophotometric method based on n → charge-transfer complex formation with chloranil. The method involves addition of cycloserine solution to chloranil reagent in borate buffer of pH 9; and heating at 65°C for 45 min. The complex formed exhibits absorption maximum of 348 nm; and Amax is linearly related to concentration over the range 2–8 μg/ml. The mean percentage found for the authentic sample is 100.32 ± 0.70. When applied to commercial capsules claimed to contain 250 mg each, the mean percentage found is 102.45 ± 1.05. These results have shown good agreement when compared with those obtained by the pharmacopoeial (B.P.) methods. 相似文献