Broadband Light-Emitting Diodes with One-Dimensional Photonic Crystal Layer

In this article, a broadband gallium-nitride-based light-emitting diode with a one-dimensional photonic crystal layer is investigated. The broadband light-emitting diode using the proposed backside reflector has high reflectance (>95%) over a 270-nm bandwidth in visible light at an arbitrary incidence angle. A broadband light-emitting diode of high output power due to the high reflectivity is achieved. Also reported are the results for light-emitting diodes by the transistor outline can (TO-can) package. The proposed light-emitting diodes possess broadband high reflected spectra, high output power for light extraction, and a good view angle.     

Chemometric tools improving the determination of anti-inflammatory and antiepileptic drugs in river and wastewater by solid-phase microextraction and liquid chromatography diode array detection

An analytical method for the simultaneous determination of seven non-steroidal anti-inflammatory drugs (naproxen, ketoprofen, diclofenac, piroxicam, indomethacin, sulindac and diflunisal) and the anticonvulsant carbamazepine in river and wastewater is reported. The method involves pre-concentration and clean-up by solid-phase microextraction using polydimethylsiloxane/divinylbenzene fibers, followed by liquid chromatography with diode array detection analysis. Owing to the fact that river water samples did not contain interferences and no sensitivity changes due to sample matrix were observed, external calibration was implemented. Standardization was also applied in order to carry out the prediction step by preparing only two diluted standards that were subjected to the pre-concentration step and a set of standards prepared in solvent. For the analysis of wastewater samples, in contrast, it was necessary to implement standard addition calibration in combination with the multivariate curve resolution-alternating least squares (MCR-ALS) algorithm, which allowed us to overcome matrix effect and exploit the second order advantage. Recoveries ranging from 72% to 125% for all pharmaceuticals proved the accuracy of the proposed method in river water samples. On the other hand, wastewater sample recoveries ranged from 83% to 140% for all pharmaceuticals, showing an acceptable performance – considering this sample contains no modeled interferences.     

CE with sequential light-emitting diode-induced fluorescence and electro-chemiluminescence detections for the determination of amino acids and alkaloids

This paper describes the determination of alkaloids and amino acids (AAs) using CE in conjunction with sequential light-emitting diode-induced fluorescence (LEDIF) and electrochemiluminescence (ECL) detections. In the CE-LEDIF-ECL system, the ECL detector was located in the outlet of the capillary, while the LEDIF detector was positioned 12 cm from the outlet. Naphthalene-2,3-dicarboxaldehyde (NDA) was used to form fluorescent AA-NDA derivatives from AAs possessing primary amino groups, while Ru(bpy)(3) (2+) was used to obtain ECL signals for analytes having secondary and tertiary amino groups. In the presence of poly(ethylene oxide), we accomplished the CE-LEDIF-ECL separation of a mixture of 12 AA-NDA derivatives, anabasine, nicotine, and proline within 11 min. This low-cost CE-LEDIF-ECL system allows the analysis of these AA-NDA derivatives and alkaloids at concentrations in the ranges of 49 nM-0.2 microM and 0.66-4.7 microM, respectively. We applied our CE-LEDIF-ECL system to the analysis of a urine sample and also to tobacco extracts. We obtained good qualitative and quantitative results when using this method with these analytes: the RSDs were below 3.0 and 2.8%, respectively. This CE-LEDIF-ECL system provides the advantages of high efficiency, speed, and sensitivity for the analysis of analytes possessing amino groups.     

Determination of Phenolic Compounds and the Antioxidant Capacity of Ximenia parviflora Benth. var. parviflora (Olacaceae) Fruit by High-Performance Liquid Chromatography with Diode Array Detection

The total phenolic and flavonoid content, phenolic composition, and in vitro antioxidant capacity of ethanolic extracts of Ximenia parviflora Benth. var. parviflora fruits collected at Zinaparo, Michoacan (in central Mexico) were determined. Fruit extracts present a high scavenging activity of 2,2-diphenyl-1-picrylhydrazyl and 2,2′-azino-bis[3-ethylbenzothiazoline-6-sulfonic acid] radicals (71.49?±?0.11% and 85.00?±?1.29% inhibition, respectively). The four phenolic compounds identified in fruit extracts by high-performance liquid chromatography with diode array detection were gallic acid, chlorogenic acid, caffeic acid, and quercetin. X. parviflora fruits may be used as a starting material for the extraction of high value antioxidant phenolic compounds with potential applications in the pharmaceutical and dietary supplement industries.     

高效液相色谱法分析生物样品中的敌鼠

 研究用阴离子交换、氰基及硅胶柱固相萃取技术分离提取血、尿、肝及肾中的敌鼠。以香豆素作内标 ,用高效液相色谱 二极管阵列检测器方法进行分离鉴定。色谱条件 :分析柱为HypersilBDSC18(5 μm ,15 0mm× 4 6mmi.d .) ,保护柱为PhenomenexODS(4mm× 3 0mmi.d .) ;流动相 :A为 0 5 %离子对A水溶液 ,B为 0 5 %离子对A甲醇溶液 ,以梯度淋洗程序分离 ;检测波长为 2 86nm。当敌鼠的质量浓度在 1mg/L～ 10 0mg/L范围时 ,其浓度同其峰面积与内标物的峰面积之比有良好的线性关系 (r=0 9999) ,最小检出限量为 5ng(按S/N =3计 )。     

Synthesis and electroluminescent performance of thermally activated delayed fluorescence‐conjugated polymers with simple formylphenyl as pendant acceptor

Formylphenyl has been demonstrated to act as an acceptor to construct thermally activated delayed fluorescence (TADF) emitter, and therefore a series of the TADF‐conjugated polymers with formylphenyl as pendant acceptor and carbazole/acridine as backbone donor are designed and synthesized. All polymers involve the twisted donor/acceptor structural moieties with the sufficiently spatial separation between the highest occupied molecular orbital and the lowest unoccupied molecular orbital as well as a small singlet/triplet splitting, and exhibit the legible TADF features confirmed by theoretical calculation and their transient decay spectra. The solution‐processed organic light‐emitting diodes using neat film of the polymers as emissive layer achieve excellent performance with the maximum external quantum efficiency (EQE) of up to 10.6%, the maximum current efficiency of up to 35.3 cd A⁻¹ and the low turn‐on voltage of 2.7 V. Moreover, the EQE still remains 10.3% at the luminance of 1000 cd m⁻² with the low driving voltage of 4.4 V and extremely small efficiency roll‐off. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 1989–1996     

基于双定性原则的高效液相色谱-二极管阵列检测法分析中药组分

双定性是根据样品的保留时间和吸收光谱的特征峰进行复合定性的一种新方法。该文基于自行设计及组装的二极管阵列检测器,构建了一套液相色谱-二极管阵列检测系统。采用该色谱系统分别对6种中药饮片中的非法添加物金胺O和枣仁天麻胶囊中的有效成分五味子醇甲进行了分离及定性研究。结果显示,在蒲黄饮片和枣仁天麻胶囊样品色谱图中均存在与目标检测物保留时间接近的色谱峰,进一步通过吸收光谱的特征峰比对,均排除了目标物存在的可能。应用结果证明,基于保留时间/吸收光谱的双定性原则,可以有效排除样品中杂质的干扰,避免假阳性结果,为中药组分研究提供了参考方法。     

Development and validation of a RP-HPLC method for Roflumilast and its degradation products

Roflumilast is a phosphodiesterase type 4 inhibitor that is administered orally as a long-term, in the clinical treatment of chronic obstructive pulmonary disease and asthma. Launched in 2010 for the European market, it currently does not have an official monograph. Here, a reproducible gradient RP-HPLC method was developed and validated for the separation and determination of Roflumilast in the presence of its six major degradation products. Separation was performed on a C₁₈ analytical column (250?×?4.6?mm, 5?µm) with a mobile phase-A of ACN and a phase-B of ammonium acetate buffer (5?mM, pH 4.2) containing triethylamine (0.5% v/v). The most effective RP-HPLC gradient program was determined to be 0/80, 35/10, 36/80, 40/80 (time in minutes/% mobile phase-B). The flow rate was 1.0?ml/min and the column temperature was 25°C. The success of separation of the degradation products with different chemical characteristics was obtained by extending the time of the gradient, changing the proportion of the mobile phases and increasing the velocity of the flow. Two detectors were evaluated for the identification of degradation products and Roflumilast: a diode-arrary detector and a charged aerosol detector. The inability of the charged aerosol detector to dectect one of the six degradation products indicated that the method developed with RP-HPLC and the diode-array detector was more suitable for Roflumilast analysis. The method was validated according to specificity, linearity, LOD, LOQ, accuracy, precision and robustness.     

Attraction behaviour of Anagrus nilaparvatae to remote lemongrass (Cymbopogon distans) oil and its volatile compounds

Utilisation of Anagrus nilaparvatae is a promising and effective method for planthoppers manipulation. Twenty-seven components of remote lemongrass (Cymbopogon distans) oil were identified by GC/MS and nine volatiles were selected for behavioural experiments. In this study, we noted that the remote lemongrass oil was attractive to female A. nilaparvatae at concentrations of 0.1 and 1 mg/L. α-Pinene, β-pinene, eucalyptol, carveol and D-carvone attracted female wasps in the dose-dependent bioassays. Blend 1 (a mixture of eucalyptol, D-carvone, carveol, α-pinene, and β-pinene with ratios of remote lemongrass oil volatiles of 625:80:11:5:3) attracted female wasps at 10 mg/L, while blend 2 (a mixture of the same five volatiles at the same loading ratio) attracted them at 0.1 and 1 mg/L. These results suggested that plant essential oils could be attractants for natural enemies to control pests. The ratios of volatiles in the mixtures affect the attractiveness of the synthetic mixtures.     

紫外臭氧处理增强溶液法MoO3薄膜的空穴注入能力

空穴注入层对有机发光二极管的性能有重要的影响,尤其是当器件中的空穴传输材料的最高占据分子轨道能级较深的时候。近年来有许多关于新型的溶液法空穴注入材料的研究。在本文中,我们对溶液法MoO₃薄膜使用了三种不同的处理方法来研究其对空穴注入性能的影响,即：在空气中150 ℃退火;在空气中150 ℃退火再紫外臭氧处理(UVO) 15 min;只进行UVO处理15 min。结果发现当MoO₃薄膜在空气中150 ℃退火后,器件的电流最小,空穴注入能力最差。而当MoO₃薄膜经过UVO处理后,器件的电流显著增大,工作电压大幅下降,器件性能接近于蒸镀的MoO₃薄膜的器件。更惊喜的是,这种改善在MoO₃薄膜仅作UVO处理后也可获得。经定量计算发现MoO₃薄膜经过UVO处理后的空穴注入效率能提高到约0.1。XPS分析表明通过UVO处理后,MoO₃薄膜中Mo⁵⁺成分减少并且薄膜表面的富氧吸附物被有效地消除,使得其化学计量基本与蒸镀的MoO₃薄膜相同。基于这种经UVO处理的溶液法MoO₃作为空穴注入层,器件的最大电流效率可达到48.3 cd∙A⁻¹。