Highly sensitive determination of tetrabromobisphenol A and bisphenol A in environmental water samples by solid‐phase extraction and liquid chromatography‐tandem mass spectrometry

Using bamboo‐activated charcoal as SPE adsorbent, a novel SPE method was developed for the sensitive determination of tetrabromobisphenol A and bisphenol A in environmental water samples by rapid‐resolution LC‐ESI‐MS/MS. Important parameters influencing extraction efficiency, including type of eluent, eluent volume, sample pH, volume and flow rate, were investigated and optimized. Under the optimal extraction conditions (eluent: 8 mL methanol, pH: 7; flow rate: 4 mL/min; sample volume: 100 mL), low LODs (0.01–0.02 ng/mL), good repeatability (6.2–8.3%) and wide linearity range (0.10–10 ng/mL) were obtained. Satisfied results were achieved when the proposed method was applied to determine the two target compounds in real‐world environmental water samples with spiked recoveries over the range of 80.5–119.8%. All these facts indicate that trace determination of tetrabromobisphenol A and bisphenol A in real‐world environmental water samples can be realized by bamboo‐activated charcoal SPE‐rapid resolution‐LC‐ESI‐MS/MS.     

Effect of spatial refractive-index nonuniformities existed in a large-scale rapid growth KDP crystal on third-harmonic conversion

Effect of spatial refractive-index nonuniformities existed in a large-scale rapid growth KDP crystal (a type I frequency doubler at the wavelength of 1053 nm) on third-harmonic conversion is studied. Spatial refractive-index nonuniformities due to imperfections in the crystal structure which prohibit the attainment of phase matching at all locations in the crystal are measured with the orthogonal polarization interferometry technique. And a third-harmonic conversion experiment is conducted on a large-scale facility to investigate the influence of refractive-index nonuniformities on conversion efficiency and third-harmonic beam nearfield. According to the experimental results, refractive-index nonuniformities in this large-scale rapid growth KDP doubler do not reduce the third-harmonic conversion efficiency, but affect the third-harmonic beam nearfield.     

A Rapid Method For the Simultaneous Estimation Of Acetyl Salicylic And Salicylic Acids In Body Fluids

Abstract

A rapid spectroscopic method for the simultaneous estimation of acetylsalicylic and salicylic acids in distilled water, guinea pig gastric juice and guinea pig plasma is described.

apid Method For the Simultaneous Estimation Of Acetyl Salicylic And Salicylic Acids In Body Fluids     

食用天然辣椒红色素中掺杂苏丹红的红外光谱快速识别

如何快速检测天然色素中是否掺杂合成色素或者工业染料是食品分析检测中的一个难题。天然辣椒红色素因兼具着色和药理功效而被广泛用于食品中,但又因其稳定性较差而被不法商贩掺杂苏丹红来获利。本文利用红外光谱技术的宏观指纹特性,对掺杂于天然辣椒红色素中苏丹红的1 621,1 500和751cm-1处的强峰,再通过二阶导数图谱分析将谱图信息放大,辅以指纹区684和496cm-1处的谱峰的佐证,可以快速识别辣椒红中是否添加有苏丹红,检测限量可以达到1%。     

基于表面增强拉曼光谱技术的豆芽6-BA残留快速检测方法

采用快速溶剂提取前处理技术与表面增强拉曼光谱(surface-enhanced Raman spectroscopy,SERS)检测技术建立豆芽中6-苄基腺嘌呤(6-benzylaminopurine,6-BA)残留物的快速定量检测方法。以自发豆芽为空白对照,通过对梯度浓度的6-BA插标豆芽提取液进行SERS检测发现,在1 002cm-1处具有明显的6-BA特征拉曼峰,且归一化处理后的特征峰峰强与6-BA浓度呈良好的线性关系,高浓度与低浓度的线性范围分别为0.5～14μg.mL-1与0.1～2μg.mL-1,最低定量检出限为0.02mg.kg-1,回收率为82.3%～95.1%,相对标准偏差小于5%。该方法重现性较好、前处理简单、全程检测耗时短、设备操作简便,为市场大规模的快速检测提供了现场、高效、灵敏的解决方案。     

A note on branch-and-cut-and-price

In this paper, we propose a methodology for branch-and-cut-and-price when cuts and columns are generated simultaneously. The methodology is illustrated with two application cases: the Split Delivery Vehicle Routing Problem (SDVRP) and the Bus Rapid Transit Route Design Problem (BRTRDP).     

On the potential energy curves of LaO molecule

Turning points for several electronic states of LaO molecule are calculated using the Rapid method by Morse function, and compared with those obtained by RKR method. The electronegativity potential function and RKR potential functions are compared for the ground state of the molecule and an estimate of dissociation energy of LaO molecule in the ground state is reported.     

Rapid Simultaneous Measurement of Hydrogen Isotopes in Aqueous Solution by 31P NMR

Integration of the ³¹P spectrum of phosphite formed after reaction of phosphorus tricholoride with partially deuterated water is found to yield an accurate measurement of the percent of deuteration (or protonation) after correction for the kinetic isotope effect. A kinetic isotope effect favoring proton reaction by a factor of 3.2 ± .25 is found. The method is tested over the range of 10% to 90% deuterium. The results are found to be accurate to ± 6% relative, which is probably limited by experimental error in the determination of the integral. Measurements outside the 10 to 90% range are possible, but require longer acquisition times because of the low signal-to-noise ratio of the small peaks.     

A simple,low-cost and rapid contrasting method for screening the particle size and monodispersity of silica microparticles by optical bright field microscopy

Silica gel microparticles can be contrasted for optical bright field microscopy by high quality china ink. This method allows the rapid screening of particle size and size distribution of Stöber silica particles. The theoretical resolution power achievable by optical microscopy can be practically reached for the first time for characterizing colorless microparticles. Costs and time for screening charges of synthesized silica particles could be reduced significantly by this method.