过氧化氢-邻氨基酚体系催化显色分光光度法测定痕量铁

在乙酸-乙酸钠缓冲溶液(pH=5.6)介质中.Fe(Ⅲ)催化H2O2氧化邻氨基酚显色,建立了催化显色分光光度法测定痕量铁的新方法.在冰水浴中反应10min,Fe(Ⅲ)线性范围为0-1.2μg/mL,回归方程为△4=0.4923C+0.0258,摩尔吸光系数为2.9×104L·mol-1·cm-1.方法用于广西东兰县产墨...     

正交优化-微波辅助提取银杏叶黄酮

采用微波萃取银杏叶黄酮类化合物,与传统溶剂萃取黄酮类化合物方法相比较,微波萃取法具有萃取时间短、溶剂用量少、耗能低、萃取效率高等优点。通过单因素实验和正交试验结果,确定提取的最佳条件为：温度55℃,功率800W,液固质量比70∶1,处理时间6min,提取率可达3.578%。在相同温度下,微波法与索氏提取法相比,微波法所需时间是索氏提取的1/80;溶剂下降30%,而且提取率增大。微波提取技术用于银杏叶中黄酮的提取具有省时、高效、节能等特点。     

混合表面活性剂-铬天青S与铜显色反应研究及应用

在曲拉通X-100(TritonX-100)和乳化剂(OP)存在下,基于Cu2+-铬天青S(CAS)的显色反应,建立了分光光度法测定微量铜的新方法.通过Cu2+与CAS-Triton X-100-OP形成灵敏度较高的多元配合物,来测量铜含量.络合物的最大吸收波长为618nm,表观摩尔吸光系数为ε=6.62×105L·m...     

缓释片中新斯的明的含量测定

采用紫外分光光度法测定新斯的明缓释片中新斯的明的含量及对其稳定性进行研究。结果表明,新斯的明浓度在80—560μg.mL-1范围内与吸光度呈良好的线性关系,回归方程为：A=0.0016C-0.0089,r=0.9999;平均回收率为100.46%,RSD为0.89%（n=9）。该法简便、快速,重现性好,结果准确可靠。     

流动注射分光光度法测定煤灰中的微量铀

在稀硝酸介质中,以2-(3-羧基苯偶氮)-7-(4-氯-2-膦酸基苯偶氮)-1,8-二羟基-3,6-萘二磺酸(CPA-mK)作为显色剂,建立了一种测定微量铀的流动注射分光光度法,在最佳实验条件下,该方法的线性范围为0-35mg/L,检出限为0.026mg/L,应用该方法测定煤灰样品中的铀,其相对标准偏差为1.8%-3....     

紫外分光光度法测定阿霉素聚乳酸微球的含量

采用复乳-溶剂挥发法制备阿霉素聚乳酸微球,通过扫描电镜观察微球的形态,采用紫外分光光度法测定徽球中阿霉素的含量.结果表明,所制备的阿霉素聚乳酸微球外形圆整,阿霉素溶液在1.70-34.1μg/mL浓度范围内线性良好,校准曲线回归方程为A=0.0422C+0.1845,相关系数r为0.9997,平均回收率为99.5%(R...     

Ultraviolet light absorber with low surface energy: synthesis and characterization

Novel fluorine-containing ultraviolet absorbers (FBPs) with low surface energy were successfully synthesized based on 2,4-dihydroxy benzophenone (BP-1), and their structures were characterized by ¹H NMR, ¹³C NMR, FTIR, and HRMS. UV absorption of FBPs was studied in 10⁻⁴ M dichloromethane (CH₂Cl₂), which demonstrated the superior UV absorption capability of FBPs (ca. ?=1.7×10⁴ to 2.2×10⁴ at λ_max) over the matrix (?=1.7×10⁴ at λ_max). Quantum chemistry calculation was performed to investigate the stable structure and UV electronic absorption bands of FBPs. The surface chemistry information of high-chlorinated polyethylene (HCPE) coating films embedded with ultraviolet absorbers (UVAs) was given by X-ray photoelectron spectroscopy (XPS) and contact angle measurement. The results show that the surface enrichment capability of FBPs is remarkably better than traditional UVAs (including BP-1, BP-3, BP-12) because of the low surface energy properties of FBPs.     

Spectrophotometric Determination of Piroxicam via Chelation with Fe(III) in Commercial Dosage Forms

The objective of this work is to develop and validate spectrophotometric method for the determination of piroxicam in commercial dosage forms. The method is based on the chelation of the drug with Fe(III) to form pink coloured metal chelate at room temperature which absorbs maximally at 504 nm. Beer's law is obeyed over the concentration range of 8–160 μg mL^?1 (A = 1.07 × 10^?3 + 7.75 × 10^?3 C). Under the optimized experimental conditions, proposed method is validated as per the International Conference on Harmonisation guidelines. The limits of detection and quantitation for the proposed method are 0.775 and 2.348 μg mL^?1, respectively. The proposed method has been successfully applied to the determination of piroxicam in commercial dosage forms. The results are compared with the reference El‐Ries et al. spectrophotometric method.     

Determination of uranium and thorium in complex samples using chromatographic separation, ICP-MS and spectrophotometric detection

The paper describes a research of possible application of UTEVA and TRU resins and anion exchanger AMBERLITE CG-400 in nitrate form for the isolation of uranium and thorium from natural samples. The results of determination of distribution coefficient have shown that uranium and thorium bind on TRU and UTEVA resins from the solutions of nitric and hydrochloric acids, and binding strength increases proportionally to increase the concentration of acids. Uranium and thorium bind rather strongly to TRU resin from the nitric acid in concentration ranging from 0.5 to 5 mol L⁻¹, while large quantities of other ions present in the sample do not influence on the binding strength. Due to the difference in binding strength in HCl and HNO₃ respectively, uranium and thorium can be easily separated from each other on the columns filled with TRU resin. Furthermore, thorium binds to anion exchanger in nitrate form from alcohol solutions of nitric acid very strongly, while uranium does not, so they can be easily separated. Based on these results, we have created the procedures of preconcentration and separation of uranium and thorium from the soil, drinking water and seawater samples by using TRU and UTEVA resins and strong base anion exchangers in nitrate form. In one of the procedures, uranium and thorium bind directly from the samples of drinking water and seawater on the column filled with TRU resin from 0.5 mol L⁻¹ HNO₃ in a water sample. After binding, thorium is separated from uranium with 0.5 mol L⁻¹ HCl, and uranium is eluted with deionised water. By applying the described procedure, it is possible to achieve the concentration factor of over 1000 for the column filled with 1 g of resin and splashed with 2 L of the sample. Spectrophotometric determination with Arsenazo III, with this concentration factor results in detection limits below 1 μg L⁻¹ for uranium and thorium. In the second procedure, uranium and thorium are isolated from the soil samples with TRU resin, while they are separated from each other on the column filled with anion exchanger in alcohol solutions. Anion exchanger combined with alcohol solutions enables isolation of thorium from soil samples and its separation from a wide range of elements, as well as spectrophotometric determination, ICP-MS determination, and other determination techniques.     

Modified iron oxide nanoparticles as solid phase extractor for spectrophotometeric determination and separation of basic fuchsin

This study presents a novel separation, preconcentration and determination of basic fuchsin (BF) in an aqueous solution by sodium dodecyl sulfate (SDS)-bounded iron oxide nanoparticles (S-IONPs). It is shown that the novel magnetic nano-adsorbent is quite efficient for the adsorption and desorption of BF at 25 °C. Different parameters such as pH, temperature, ionic strength and composition of desorbent solvent were optimized. The effect of some co-existing ions on the determination was investigated. The nanoparticles were analyzed by transmission electron microscopy (TEM) and the sizes of S-IONPs were in the range of 20-100 nm. The method showed good linearity for the determination of BF in the range of 10-300 ng mL⁻¹ with a regression coefficient of 0.9989. The limit of detection (LOD) (signal-to-noise ratio of 3:1) was 0.0073 μg L⁻¹ and the relative standard deviation (RSD) for 0.03 μg mL⁻¹ and 0.2 μg mL⁻¹ of BF were 4.53% and 4.73%, respectively. The BF was determined successfully in spiked samples of Karoon River water.