Analytical Utility of the Unique Colour Reaction Between Uranyl Ions and Alizarin Fluorine Blue

Abstract

The uranyl-alizarin fluorine blue chelate complex shows an absorption peak at 560 nm, 30 nm higher than that of any other single metal complex of the reagent. The complex shows, at pH 4.5, a conditional stability constant of 2.3 × 10⁶ litres mole^?1 and molar absorptivity of 4100 litres mole^?1 cm^?1. Study of the feasibility of using this reaction for the photometric determination of Uo₂ ⁺² in both one and two liquid phase systems reveals serious interference from other metal ions.     

新显色剂二溴羟基苯基荧光酮的氧化显色反应及双波长分光光度法测定废水中的铬

本文利用光度法和电位滴定法探讨了铬(Ⅵ)与二溴羟基苯基荧光酮(DBHPF)的显色反应,发现在酸性介质中为DBHPF的氧化显色反应。DBHPF曾成功地应用于钛钼钨锡等元素的测定。本文利用Cr(Ⅵ)与DBHPF的氧化显色反应,进一步研究了双波长分光光度法测定Cr(Ⅵ)的条件。应用拟定的新方法测定了电镀废水中的铬(Ⅵ)和总铬量,结果满意。     

新试剂苯并噻唑重氮氨基偶氮苯与镉的显色反应研究及其应用

在Ｔｒｉｔｏｎ Ｘ－１００存在下，ｐＨ９．０－１０．０时，新试剂苯并噻唑重氮氨基偶氮苯与镉形成３：１的橙红色络合物，最大吸收波长位于５３０ｎｍ，表观摩尔吸光系数为１．９１×１０＾－５Ｌ．ｍｏｌ＾－１；ｃｍ＾－１，镉量在０－１２μｇ／２５ｍＬ范围内遵守比尔定律。在混合掩蔽剂存在下，显色反应具有良好的选择性，直接应用于工业废水中微量镉的测定，获得了满意的结果。     

A Brief History of Colour,the Environmental Impact of Synthetic Dyes and Removal by Using Laccases

The history of colour is fascinating from a social and artistic viewpoint because it shows the way; use; and importance acquired. The use of colours date back to the Stone Age (the first news of cave paintings); colour has contributed to the social and symbolic development of civilizations. Colour has been associated with hierarchy; power and leadership in some of them. The advent of synthetic dyes has revolutionized the colour industry; and due to their low cost; their use has spread to different industrial sectors. Although the percentage of coloured wastewater discharged by the textile; food; pharmaceutical; cosmetic; and paper industries; among other productive areas; are unknown; the toxic effect and ecological implications of this discharged into water bodies are harmful. This review briefly shows the social and artistic history surrounding the discovery and use of natural and synthetic dyes. We summarise the environmental impact caused by the discharge of untreated or poorly treated coloured wastewater to water bodies; which has led to physical; chemical and biological treatments to reduce the colour units so as important physicochemical parameters. We also focus on laccase utility (EC 1.10.3.2), for discolouration enzymatic treatment of coloured wastewater, before its discharge into water bodies. Laccases (p-diphenol: oxidoreductase dioxide) are multicopper oxidoreductase enzymes widely distributed in plants, insects, bacteria, and fungi. Fungal laccases have employed for wastewater colour removal due to their high redox potential. This review includes an analysis of the stability of laccases, the factors that influence production at high scales to achieve discolouration of high volumes of contaminated wastewater, the biotechnological impact of laccases, and the degradation routes that some dyes may follow when using the laccase for colour removal     

固相萃取-高效液相色谱法测定葡萄酒中白藜芦醇及其糖苷异构体

建立了固相萃取-高效液相色谱(SPE-HPLC)测定葡萄酒中白藜芦醇及其糖苷异构体的方法,并用此方法测定了市售的15种葡萄酒中顺反式白藜芦醇及其糖苷的含量。实验确定了葡萄酒样品中的白藜芦醇及其糖苷的固相萃取方法,通过优化萃取条件,有效地去除了葡萄酒中大量干扰成分。采用Hypersil C18柱(4.6 mm i.d.×250 mm,5μm)分离,以乙腈-水为流动相,线性梯度洗脱,用二极管阵列检测器分别于288 nm和306 nm波长下检测,4种组分分离良好,提高了分析结果的准确性。采用外标法定量,4种组分的质量浓度与其峰面积在一定的范围内有良好的线性关系,相关系数为0.9973～0.9999。4种组分的平均加标回收率为97.4%～98.8%(相对标准偏差为2.1%~3.2%),检测限为0.002~0.005 mg/L。对市售15种葡萄酒的检测结果表明,白藜芦醇作为葡萄酒中重要的生物活性成分,其含量与葡萄酒的酿造方式、葡萄品种、葡萄产地有密切的关系。该方法还可用于其他天然产物中白藜芦醇及其糖苷异构体的测定。     

钨与溴邻苯三酚红—罗丹明6G协同显色的研究及其应用

本文研究了聚乙二醇辛基苯基醚存在下，在硫酸介质中，钨与溴邻苯三酚红和罗丹明６Ｇ双试剂协同显色反应，反应结果形成红色络合物，最大吸收波长５７８ｎｍ，表观摩尔吸光系数４．４１×１０＾５Ｌ．ｍｏｌ＾－１．ｃｍ＾－１。钨量在０－８μｇ／２５ｍｌ范围内符合比尔定律。     

Phenolic Profile,Antioxidant Capacity and Antimicrobial Activity of Nettle Leaves Extracts Obtained by Advanced Extraction Techniques

Nettle is a widely known plant whose high biological activity and beneficial medicinal effects are attributed to various bioactive compounds, among which polyphenols play an important role. In order to isolate polyphenols and preserve their properties, advanced extraction techniques have been applied to overcome the drawbacks of conventional ones. Therefore, microwave-assisted extraction (MAE) has been optimized for the isolation of nettle leaves polyphenols and it was compared to pressurized liquid extraction (PLE) and conventional heat-reflux extraction (CE). The obtained extracts were analyzed for their individual phenolic profile by UPLC MS² and for their antioxidant capacity by ORAC assay. MAE proved to be the more specific technique for the isolation of individual phenolic compounds, while PLE produced extracts with higher amount of total phenols and higher antioxidant capacity. Both techniques were more effective compared to CE. PLE nettle extract showed antimicrobial activity against bacteria, especially against Gram-negative Pseudomonas fragi ATCC 4973 and Campylobacter jejuni NCTC 11168 strains. This suggests that PLE is suitable for obtaining a nettle extract with antioxidant and antimicrobial potential, which as such has great potential for use as a value-added ingredient in the food and pharmaceutical industry.     

Volatiles Composition and Antimicrobial Activities of Areca Nut Extracts Obtained by Simultaneous Distillation–Extraction and Headspace Solid-Phase Microextraction

The volatile components of areca nuts were isolated by headspace solid-phase microextraction (HS-SPME, DVB/CAR/PDMS fiber extraction) and simultaneous hydrodistillation–extraction (SHDE) and analyzed by gas chromatography/mass spectrometry. Furthermore, all SHDE fractions were tested for antimicrobial activity using the disk diffusion method on nine Gram-negative and Gram-positive bacteria (Bacillus subtilis, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus agalactiae, Streptococcus canis, Streptococcus pyogenes, and Candida albicans). In total, 98 compounds (mainly alcohols, carbonyl compounds, fatty acids, esters, terpenes, terpenoids, and aliphatic hydrocarbons) were identified in SHDE fractions and by using SPME extraction Fatty acids were the main group of volatile constituents detected in all types of extracts. The microorganism most sensitive to the extract of the areca nut was Streptococcus canis. The results can provide essential information for the application of different treatments of areca nuts in the canning industry or as natural antibiotics.     

Multi-Year Study of the Chemical and Sensory Effects of Microwave-Assisted Extraction of Musts and Stems in Cabernet Sauvignon,Merlot and Syrah Wines from the Central Coast of California

Microwave technology (MW) was applied to musts and stems over three consecutive vintages in Cabernet Sauvignon, Merlot and Syrah wines from California (USA). Stems were added to musts at a rate of 50 and 100% (50% Stems and 100% Stems), either as untreated or after MW (50% MW Stems and 100% MW Stems). Stem additions lowered ethanol (up to 1.15% v/v reduction), but increased pH (up to 0.16 units) and the tannin content of the wines. In 2016, tannins increased by 103% (100% Stems), and 124% (100% MW Stems). In 2017, tannins increased by 39% in stem-added Merlot wines and by 63% (100% Stems) and 85% (100% MW Stems) in Syrah wines. In 2018, tannins in Syrah wines increased by 250% (100% MW Stems) and by 743% (100% Stems). Wines made with 50% Stems exhibited intermediate tannin contents. Must MW increased flavonols (up to 278% in Syrah wines), monoglucosylated, acylated and anthocyanin-derived pigments. Stem additions reduced wine color and polymeric pigment formation in Syrah. Must MW decreased the perception of coarseness and herbaceous flavors in Merlot, whereas stem additions increased herbaceous aromas in Syrah. Despite higher tannin contents in stem-added wines, no concomitant increases in astringency were observed.     

HRGC/FID and HRGC/MSD Analysis of the Secondary Metabolites Obtained by Different Extraction Methods from Lepechinia schiedeana,and in Vitro Evaluation of Its Antioxidant Activity

Steam distillation (SD), simultaneous distillation-solvent extraction (SDE), microwave-assisted solvent extraction (MWE), and supercritical (CO₂) extraction (SFE) were used to isolate secondary metabolites from Lepechinia schiedeana. The various extracts were analyzed by capillary gas-chromatography, on poly (dimethylsiloxane) (DB-1) and poly(ethyleneglycol) (INNOWAX), 60 m columns, using FID or MSD (EI, 70 eV). Kováts indexes, mass spectra, or standard compounds were employed for compound identification. 43, 61, 67, and 79 compounds at concentrations above 0.01% were detected in the SD, SDE, MWE, and SFE extracts, respectively. Ledol, C₁₅H₂₆O, was the major constituent (20.04–36.87%) in all extracts. Oxygenated sesquiterpenes (24.36–43.14%), C₁₀H₁₆, monoterpenes (27.70–39.87%), and C₁₅H₂₄, sesquiterpenes (10.04–22.22%) were the main groups of compounds present in SD, SDE, MWE, and SFE extracts. Heavy hydrocarbons (C_n > 15), diterpenoids, and phytosterols were found only in MWE and SFE extracts. The antioxidant activity of Lepechinia schiedeana was measured by the HRGC quantification of the volatile carbonyl compounds, final products of lipoxidation, released in a model lipid system (sunflower oil) by the effect of the Fenton reagent. The concentration of volatile carbonyl compounds decreased by 65% when lipid oxidation was induced in the presence of macerated Lepechinia plant. The protection of polyunsaturated acids in sunflower oil was also studied by measuring their concentrations after heating of the oil (180°C, 2 h) with and without macerated Lepechinia plant.     

A Comparative Study of Homemade C18 and Commercial C18 Sorbents for Preconcentration of Lead by Minicolumn Solid Phase Extraction

A comparative study of commercial C₁₈ chemically immobilized on silica and homemade C₁₈, as sorbents for Pb complexed with O,O-diethyl-dithiophosphate (DDTP) in a flow injection preconcentration system is reported. The homemade C₁₈ sorbent was obtained by sorption of poly(methyloctadecylsiloxane) (PMODS) on the silica support followed by immobilization using thermal treatment. The method follows the concept of green chemistry, since there are no toxic residues after synthesis. The complexed Pb was formed in 1.0molL^–1 HCl medium and retained on the minicolumn filled with the sorbents. The elution was carried out using ethanol, and the richest 210µL fraction was collected and analyzed by flame atomic absorption spectrometry. Chemical and flow variables were optimized for each sorbent. The results demonstrated that the performance of the proposed homemade C₁₈ sorbent for preconcentration of Pb complexed with DDTP is very similar to commercial C₁₈ chemically bonded on silica. By processing 25mL, the enrichment factors were 129 and 125 for commercial C₁₈ and homemade C₁₈, respectively. The limit of detection for commercial and homemade C₁₈ was 0.2µgL^–1 and 0.6µgL^–1, respectively. The relative standard deviation (RSD) was lower than 1.2% for both sorbents for a Pb concentration of 100µgL^–1. The method was also applied successfully to the analysis of water samples, and the accuracy was tested by recovery measurements on spiked samples and biological reference material.     

Rapid Formation of the Textured (Bi,Pb)2(Sr,Ca)4Cu3Oy Superconductor by Multiple Pressing and Sintering Process

A superconducting (Bi, Pb)₂(Sr, Ca)₄Cu₃O₂ material has been prepared by tbe oxalate coprecipitation method. The high-Tc 110 K phase was effectively promoted by application of an intermediate grinding and pressing between the sintering heat treatments. The powder X-ray diffraction shows the existence of single high-Tc and high-textured microstructures with strong (001) reflections within a short sintering time ( 18 h). The morphology of the sintered samples was examined by scanning electron microscopy (SEM). Also, the kinetics of the formation of the high-Tc phase were investigated by the isothermal method. A possible mechanism of the formation of high-Tc 2223 phase was proposed.     

Exploring the Mechanism of Ionic Liquids to Improve the Extraction Efficiency of Essential Oils Based on Density Functional Theory and Molecular Dynamics Simulation

Highlights

• According to the design of the experiment (DoE), multivariate analysis models were used to optimize the critical process parameters combined with multi-objective optimization.
• Based on the optimized operating conditions, the MILT-HD method not only enhances the extraction efficiency from Amomi fructus but also reduces energy demands and CO₂ emissions.
• Based on the density functional theoretical (DFT) and molecular dynamics (MD) simulations, the mechanisms for ionic liquids (ILs) to improve the extraction efficiency of essential oil was comprehensively revealed.

AbstractIn this paper, Amomi fructus (Latin) was used to explore the mechanism of ionic liquids (ILs) in improving the extraction efficiency of essential oils. Microwave assisted ionic liquid treatment followed by a hydro-distillation (MILT-HD) process for isolating Amomi fructus essential oil was optimized by multi-objective optimization. Under optimum operating conditions, the IL-assisted extraction method not only enhances extraction efficiency but also reduces energy demands and CO₂ emissions. Since the hydrogen bond structure network of cellulose in the cell wall is an important reason for hindering diffusion of essential oils, the mechanism of ILs was explored by density functional theoretical (DFT) and molecular dynamics (MD) simulations. According to DFT calculations, ILs can facilitate the cleavage of cellulose chains and have strong non-covalent interactions with cellulose. Based on the MD simulations, the degree of destruction of the cellulose hydrogen bond structure was explored. According to the DFT and MD simulations, the ILs can significantly destroy cellulose structure, thereby promoting essential oil release from the plant. These results were confirmed by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR). This work is conducive to better understand the MILT-HD process for isolating essential oil and comprehensively understand the mechanism of ILs in the extraction process.     

Differentiation between the Green and Turkish Blue Solid Solutions of Vanadium in a Zircon Lattice Obtained by the Sol-Gel Process

In this communication, zircon containing vanadium samples which gradually turn greenish have been prepared by controlling the composition (fluoride addition) and the method of preparation (sol-gel, ceramic and solid impregnation) in order to investigate how to affect the shape and size of the vanadium particles, and their location, clustering and distribution. The level of green color, and consequently the amount of V5+ in the sample, could be associated with the development of an Si-O-Si network in the zircon lattice, bonding with the highly reactive zirconium precursors.     

微波辅助提取石蒜和虎杖中有效成分的动力学机理

以鳞茎药材石蒜(Lycoris radiata)和根茎药材虎杖(Rhizma Polygoni Cuspidati)作为研究对象,采用微波辅助提取(MAE)石蒜中的石蒜碱、力可拉敏和加兰他敏以及虎杖中的大黄素和白藜芦醇,研究了提取过程的动力学机理。分别对这5种组分在提取温度、提取时间、搅拌速度和颗粒度等因素影响下MAE过程的动力学行为和特征进行了探讨,并与常规的溶剂回流提取法(SRE)进行对比研究,采用扫描电镜观察了MAE和SRE提取后样品的表面细胞结构。结果表明,石蒜和虎杖的MAE提取过程具有明显不同的动力学特征,其机理分别基于内部扩散传质控制和细胞破壁引起的界面反应控制。与SRE相比,MAE能引起石蒜和虎杖的细胞结构发生显著变化,降低了表观活化能Ea,组分的表观速率常数明显增大。     

YLuAG:Ce粉体的发光及闪烁特征: 制备方法及缺陷效应

采用硝酸盐热解法(NP)、碳酸氢铵共沉淀法(CP)以及柠檬酸盐燃烧法(CC)分别制备了YLuAG:Ce (Y_0.600Lu_2.364Al₅O₁₂:Ce_0.036)荧光粉体. 通过傅里叶变换红外光谱(FTIR), X射线衍射(XRD), 透射电子显微镜(TEM), 光致发光(PL)及热释光(TL)等表征手段研究了不同方法制备粉体的反应结晶过程、晶粒形貌、激发发射光谱、闪烁性能等. 对比研究表明, 三种方法制备的YLuAG:Ce粉体其表面及体相缺陷数量及分布存在差异, 从而导致了发射光谱峰位的偏移和快慢衰减时间分量的比例变化. 粉体的热释光谱分析结果进一步显示: 不同粉体热释光谱的主发射峰峰位及强度明显不同, 从侧面说明了合成方法诱发了粉体内的缺陷, 而粉体内具有不同陷阱深度的缺陷数量及陷阱复合几率对材料发光性能有较大影响.     

人工神经网络用于Ln3+的萃合及协萃体系稳定常数的关联和预测

研究了影响Ln^3 离子的萃合及协萃合物稳定性的有关因素。以Ln^3 离子的半径、电负性，4f电子排布周期因子q(本文自定义）以及基态L值等为参数，使用函数连接型神经网络（FLN），对Ln^3 的HTTA萃合物，HTTA－P350协萃合物及HTTA－TPB协萃合物的稳定常数分别进行了非线性关联和预测，获得了好的结果。     

Real-Time Distinguishing of the Xylene Isomers Using Photoionization and Dissociation Mass Spectra Obtained by Femtosecond Laser Mass Spectrometry (FLMS)

Abstract

Distinguishing chemicals and improvement on analytical methods has a direct impact on modern chemical analysis. In this work, the dissociative ionization of xylene isomers was investigated using a femtosecond laser mass spectrometry (FLMS) method with a custom-built linear time-of-flight (TOF) instrument. Laser beams at 800?nm and 400?nm were used and intensity-dependent analysis of the obtained mass spectra was performed using principal component analysis (PCA) to distinguish the xylene isomers, which give identical mass spectra in appearance that cannot be distinguished using normal mass spectrometry methods. The results show that there is a statistically highly significant difference between the xylene isomers for two principal components (1 ? α?>?99.99%) and minimal information loss (<5%) took place during the PCA procedure. Also, the use of the k-medoid clustering method showed that the isomers may be distinguished in real-time for a wide range of ionization laser pulse powers with approximately 99% accuracy. The results suggest that real-time isomer analysis by the FLMS method is suitable for mass spectral identification applications. The FLMS method has been shown to be an important alternative to other mass spectrometric methods that use different ionization mechanisms.     

Influence of the Nature of Iron, Aluminium and Yttrium Organometallic Nanocluster Precursors on the Formation Mechanism of Ceramic ZrO2 Obtained by Sol-Gel Method

To obtain new effective precursors for single phase ceramic zirconia materials by the alkoxide route, three heterometallic iron-yttrium acetylacetonate complexes were synthesized by electrochemical anodic dissolution in acetylacetone. The structure and properties of the synthesized complex oxides were studied by XRD, EXAFS, magnetic susceptibility and Mössbauer. It was shown that, for iron-containing gels and oxides, Fe³⁺ ions—interchangeably with Y³⁺—participate in the oxide formation mechanism. The sets of interatomic distances found by EXAFS in the iron-yttrium precursor and in the zirconia gel are practically equal. The presence of structure fragments formed by these interactions—and especially by direct Fe-Y bonds in the precursors—allows single-phase triple ceramic oxides to form.     

梨、苹果和香蕉中8种多酚类物质的微波提取与高效液相色谱法测定

以卡瑞（Carrez）试剂为样品净化剂,采用聚焦微波萃取系统（FMASE）提取水果中的多酚类物质,建立了水果中8种常见多酚化合物的反相高效液相色谱（RP-HPLC）分析方法,比较和探讨了样品的微波提取法与常规榨汁法。结果表明,微波提取法中各组分均能得到基线分离,标准曲线相关系数均达0.999以上,加标回收率为90%-110%,相对标准偏差小于3.6%。对梨、苹果及香蕉的测定结果表明,果皮比果肉含有的多酚种类多、含量相对较高;梨皮中芦丁和绿原酸含量相对较高;香蕉皮中儿茶素含量最高。应用微波提取制样法较常规榨汁法检测到更多种的多酚类物质。