Colorimetric technique for the detection of carbofuran and its application in various environmental samples

A large variety of pesticides have been used in the agriculture area to raise the quality, extend and yield storage life of crops. The nonstop uses of these pesticides have resulted in pollution of the environment and also caused risk to human health. For the rapid detection of selective CBFpesticide, we developed a simple and sensitive colorimetric detection method based on azo-coupling reaction. After a simple pre-treatment of carbofuran (2, 2-dimethyl-2, 3-dihydro-7-benzofuranyl N-methyl carbamate) (CBF) (1000 ​μg ​mL⁻¹) with a diazotized solution, the resulting is rapidly undergoing azo-coupling reaction with p-aminoantipyrine (1% alcoholic) with a dramatic color change only in few minutes. Finally, we successfully applied the concentrations of CBF pesticide on vegetable, fruit, soil, and water samples in the presence of natural interferences using UV–Vis spectrophotometer and FTIR with limits of detection at 0.004μgmL⁻¹. CBF had recoveries in the range of 93–98%, with relative standard deviation values less than 2% and good linearity was achieved with r ​≥ ​0.98. The inhibition rate was linear with CBF concentration in the range of 1μgmL⁻¹ to 10μgmL⁻¹. The proposed method applies to analyze CBF pesticide in real samples. FTIR technique was used to consider and gain structural information about the existing intermolecular interactions for vegetable samples.     

Spectrophotometry Determination of Amitriptyline-HCl in Pure and Pharmaceutical Preparations.

ABSTRACT

Amitriptyline-HCl reacts with ammonium molybdate in concentrated sulphuric acid after heating for 20 min. at 100°C to give a green colour having maximum absorbance at 660 nm. The reaction is selective for amitriptyline with 0.01 mg/10ml as visual limit of identification and provides a basis for a new spectrophotometric determination. The reaction obeys Beer's law from 0.01 mg to 1.4 mg/10ml of amitriptyline-HCl and the relative standard deviation is 0.35%. The quantitative assessment of tolerable amount of other drags is also studied.     

Imprinted sol-gel materials for monitoring degradation products in automotive oils by shear transverse wave

Titania sol-gel layers imprinted with capric acid have been used as synthetic receptors for highly sensitive detection of oxidized products resulting from degradation of automotive engine oil. These layers have been applied as sensitive coating material on shear transverse wave (STW) resonators of frequencies ranging from 100 MHz to 430 MHz. A relatively small size of STW resonators, i.e. about 2 mm for 430 MHz makes these devices extremely useful while considering the concept of miniaturization. It has been proved experimentally that by increasing fundamental resonance frequency of these devices, a very high sensor response i.e. 22 kHz up to 460 kHz can be generated. The geometry of long chain capric acid fits best as recognition element in the synthesis of imprinted TiO₂ network. The thin titania layers coated on transducer surface provide excellent diffusion pathways to oxidized products of waste engine oil for selective and reversible re-inclusion i.e. recovery time of 30 min. Viscosity effects of oxidized engine oil can be minimized by shear waves which do not dissipate considerable amount of energy that ensure smooth liquid phase operation. Different oxidized products i.e. carbonic acids and esters can be characterized in lubricant via infra-red (IR) spectroscopy. The increasing IR absorbance of different waste oil samples is a clear indication of increasing concentration of carbonyl group. The IR absorbance of carbonyl groups is directly correlated to the age of respective waste engine oil samples and a quantitative relationship between sensor responses from STWs and IR absorbance was also developed.     

Growth, structural and optical properties of CdxZn1−xS thin films deposited using spray pyrolysis technique

Cd_xZn_(1−x)S (x = 0, 0.2, 0.4, 0.6, 0.8, and 1) thin films were deposited by the chemical spray pyrolysis technique using a less used combination of chemicals. Depositions were done at 573 K on cleaned glass substrates. The composition, surface morphology and structural properties of deposited films were studied using EDAX, SEM and X-ray diffraction technique. XRD studies reveal that all the films are crystalline with hexagonal (wurtzite) structure and inclusion of Cd into the structure of ZnS improved the crystallinity of the films. The value of lattice constant ‘a’ and ‘c’ have been observed to vary with composition from 0.382 to 0.415 nm and 0.625 to 0.675 nm, respectively. The band gap of the thin films varied from 3.32 to 2.41 eV as composition varied from x = 0.0–1.0. It was observed that presence of small amount of cadmium results in marked changes in the optical band gap of ZnS.     

Biosynthesis of silver nanoparticle using flowers of Calotropis gigantea (L.) W.T. Aiton and activity against pathogenic bacteria

Silver nanoparticles (AgNPs) from silver nitrate solution are carried out using the flower extract of Calotropis gigantea. Silver nanoparticles were characterized by UV–vis spectrophotometer, X-Ray diffractometer (XRD). Reduction of silver ions in the aqueous solution of silver during the reaction was observed by UV–vis spectroscopy. Crystalline nature of synthesized silver nanoparticles was studied by XRD pattern, refraction peak using the Scherrer’s equation. Antibacterial activity of the silver nanoparticles was performed by disc diffusion method against Bacillus subtilis, Pseudomonas putida and Escherichia coli. The antibacterial activity of synthesized silver nanoparticles by flower extract of C. gigantea was found against B. subtilis (10 mm). Synthesised AgNPs has the efficient antibacterial activity against Gram positive bacteria.     

PBO的合成、表征及磷含量的测定

以4,6-二氨基-1,3-苯二酚盐酸盐和对苯二甲酸为原料,多聚磷酸为介质,缩聚得到聚对苯撑苯并二噁唑(PBO).通过实验得到最佳条件:聚合反应在减压及氮气保护下进行,聚合温度100℃~180℃,控制最终w(P2O5)=83%~84%.通过红外光谱、热重分析对PBO进行了表征.结果表明,合成的PBO具有优良的耐热性能.采用分光光度法测定聚合物中残余的磷含量,测定了最大吸收波长、绘制了磷标准曲线、考察了回流时间对聚合物中残余磷含量的影响.实验结果表明硫酸为溶剂、测定波长710 nm、当聚合物在水中回流30 h后,磷含量≤0.12%.     

Sedimentary siloxanes: A depositional history

A Puget Sound sediment core has been quantitatively analyzed for organic silicon content, as derived from post-1945 release of poly(organo)-siloxanes (silicones). The sedimentary silicone data record and preserve at depth, a smeared event horizon, or first appearance of silicone in the sediment column. Core samples older than 50 years showed no detectable silicone as measured by a new procedure utilizing inductively coupled plasma (ICP) emission spectroscopy after solvent extraction to collect the silicone from gram-sized sediment core samples.     

原子吸收分光光度计日常维护及常见故障排除

介绍了原子吸收分光光度计日常维护注意事项及常见故障排除方法.     

便携式分光测色仪光学设计

光学系统是分光光度计的核心部分,以光谱仪基本原理和光学设计理论为基础,以便携化、低成本、且满足设计要求的光谱范围和分辨率为具体设计目标,对李特洛系统、艾伯特-法斯梯系统、切尔尼-特纳系统、交叉式切尔尼-特纳系统这4种可行的设计方案进行了比较与分析,提出以平面衍射光栅作为色散元件的非对称交叉式C zerny-Turner结构作为该设计的系统结构。用光学软件对该系统进行模拟和优化,设计结果表明:设计的系统光谱范围为360 nm～740 nm,光谱分辨率为10 nm、F数为5.25、光谱展开为44.1 mm、系统体积约80 mm×69 mm×62 mm,满足精度高、体积小及成本低等设计要求。     

Characterization of photoluminescence spectra from poly allyl diglycol carbonate (CR-39) upon excitation with the ultraviolet radiation of various wavelengths

The induced photoluminescence (PL) from the π-conjugated polymer poly allyl diglycol carbonate (PADC) (CR-39) upon excitation with the ultraviolet radiation of different wavelengths was investigated. The absorption and attenuation coefficients of PADC (CR-39) were recorded using a UV–visible spectrometer. It was found that the absorption and attenuation coefficients of the PADC (CR-39) exhibit a strong dependence on the wavelength of ultraviolet radiation. The PL spectra were measured with a Flormax-4 spectrofluorometer (Horiba). PADC (CR-39) samples were excited by ultraviolet radiation with wavelengths in the range from 260 to 420 nm and the corresponding PL emission bands were recorded. The obtained results show a strong correlation between the PL and the excitation wavelength of ultraviolet radiation. The position of the fluorescence emission band peak was red shifted starting from 300 nm, which was increased with the increase in the excitation wavelength. The PL yield and its band peak height were increased with the increase in the excitation wavelength till 290 nm, thereafter they decreased exponentially with the increase in the ultraviolet radiation wavelength. These new findings should be considered carefully during the use of the PADC (CR-39) in the scientific applications and in using PADC (CR-39) in eyeglasses.