优氯净的分析测定新方法研究

本文利用优氯净对紫外光有吸收的特性,采用紫外分光光度法对优氯净的含量进行测定.实验考察了测定过程中可能存在的各种影响因素,证明此方法是一种简便的、高效可行的优氯净的分析方法.     

Uncertainty in the determination of glucose in aqueous solutions by high‐performance liquid chromatography with evaporative light scattering detection

The determination of glucose and other carbohydrates is the most widespread chemical analysis that is performed within the industries of food, beverage, forage, biomass, pulp and paper, pharmaceuticals among others. Besides that, sugar refineries need to control their products, by‐products and effluents, and furthermore, glucose in the sucrose refining process, is considered an impurity, which shall be controlled. Being HPLC the most currently instrumental technique used for glucose analysis, the evaporative light scattering detector (ELSD) offers advantages (sensitivity, possibility for operating in gradient mode) over the also used refractive index detector. In this work, an HPLC‐ELSD methodology was optimised and validated, aiming the estimate of the uncertainty associated with the results at low levels of concentration of glucose to be measured. Linearity of the response was obtained in the range of glucose concentrations from 20 to 300 mg/L, with an analysis time of 10 min. The global uncertainty was estimated accordingly to the bottom‐up approach used by Eurachem. It was 13% on average for concentrations from 100 to 300 mg/L. For lower concentrations, uncertainty increased significantly up to 30% in the vicinity of the LOD of the method.     

Combination of mid- and near-infrared spectroscopy for the determination of the quality properties of beers

The combination of infrared (MIR) and near-infrared (NIR) spectroscopy has been employed for the determination of important quality parameters of beers, such as original and real extract and alcohol content. A population of 43 samples obtained from the Spanish market and including different types of beer, was evaluated. For each technique, spectra were obtained in triplicate. In the case of NIR a 1 mm pathlength quartz flow cell was used, whereas attenuated total reflectance measurements were used in MIR. Cluster hierarchical analysis was employed to select calibration and validation data sets. The calibration set was composed of 15 samples, thus leaving 28 for validation. A critical evaluation of the prediction capability of multivariate methods established from the combination of NIR and MIR spectra was made. Partial least squares (PLS) and artificial neural networks (ANN) were evaluated for the treatment of data obtained in each individual technique and the combination of both. Different parameters of each methodology were optimized. A slightly better predictive performance was obtained for NIR-MIR combined spectra, and in all the cases ANN performs better than PLS, which may be interpreted from the existence of some non-linearity in the data. The root-mean-sqare-error of prediction (RMSEP) values obtained for the combined NIR-MIR spectra for the determination of real extract, original extract and ethanol were 0.076% w/w, 0.14% w/w and 0.091% v/v.     

CdSe quantum dots as luminescent probes for spironolactone determination

Based on the quenching of the fluorescence of CdSe quantum dots (QDs) by spironolactone, a simple, rapid and specific method for spironolactone determination was proposed. In the optimum conditions, spironolactone concentration versus quantum dot fluorescence gave a linear response with an excellent 0.997 correlation coefficient, between 2.5 and 700 mg/mL (6.0-1680 μmol/L) and the limit of detection (S/N = 3) was 0.2 μg/mL (0.48 μmol/L). The contents of spironolactone in pharmaceutical tablets were determined by the proposed method and the results agreed with the claimed values. The possible mechanism for the reaction was also discussed.     

质谱中的立体化学效应（19）──对映异构的α－苯乙胺光学纯度质谱测定

质谱中的立体化学效应（１９）──对映异构的α－苯乙胺光学纯度质谱测定吴忆南，涂亚平，潘远江，陈耀祖（浙江大学化学系，杭州，３１００２７，兰州大学应用有机化学国家重点实验室）崔勐，宋凤瑞，刘淑莹（中国科学院长春应用化学研究所）关键词对映体，光学纯度，质...     

The use of graphene-based magnetic nanoparticles as adsorbent for the extraction of triazole fungicides from environmental water

A graphene-based magnetic nanocomposite (graphene-ferriferrous oxide; G-Fe(3) O(4) ) was synthesized and used as an effective adsorbent for the preconcentration of some triazole fungicides (myclobutanil, tebuconazole, and hexaconazole) in environmental water samples prior to high-performance liquid chromatography-ultraviolet detection. The method, which takes the advantages of both nanoparticle adsorption and magnetic phase separation from the sample solution, could avoid the time-consuming experimental procedures commonly involved in the traditional solid phase extraction such as centrifugation and filtrations. Various experimental parameters affecting the extraction efficiencies such as the amount of the magnetic nanocomposite, extraction time, the pH values of the sample solution, salt concentration, and desorption conditions were investigated. Under the optimum conditions, the enrichment factors of the method for the three analytes were 5824, 3600, and 4761, respectively. A good linearity was observed in the range of 0.1-50 ng/mL for tebuconazole and 0.05-50 ng/mL for myclobutanil and hexaconazole, respectively, with the correlation coefficients ranging from 0.9992 to 0.9996. The limits of detection (S/N = 3) of the method were between 0.005 and 0.01 ng/mL. The results indicated that as a magnetic solid-phase extraction adsorbent, the graphene-ferriferrous oxide (G-Fe(3) O(4) ) has a great potential for the preconcentration of some compounds from liquid samples.     

紫外光引发剂907及其反应中间体的气相色谱测定

建立了光引发剂907合成工艺控制中反应原料、中间体及产物的气相色谱分析方法。采用SE-54石英毛细管柱,程序升温进行分离,氢火焰离子化检测器(FID)进行检测。结果表明,原料苯甲硫醚,反应中间体807A、807B、907C和产物907线性范围分别为0.2～14.0μg/mL、0.4～20.0μg/mL、0.5～22.0μg/mL和0.6～19.0μg/mL,线性相关系数R均大于0.999,相对标准偏差小于2.5%,回收率为93.6%～106.8%。产物结构通过红外光谱进行表征。该方法线性关系、准确度和精密度良好,适用于光引发剂907合成工艺的快速监控及产品定量分析。     

顶空气相色谱法测定烟用胶中残余单体

采用顶空气相色谱(HS-GC)法对卷烟用胶中甲基丙烯酸甲酯、甲基丙烯酸乙酯、甲基丙烯酸丁酯、丙烯酸甲酯、丙烯酸乙酯、丙烯酸丁酯和乙酸乙烯酯7种残余单体进行了分析。方法采用DB-VRX石英弹性毛细管色谱柱分离,氢火焰离子化检测器检测。7种单体能够完全分离,线性良好,线性相关系数在0.9985～0.9992之间,检测限在0.0030～0.0039mg/mL范围,相对标准偏差(RSD)小于1.92%。该方法操作简便、快速、高效、准确、灵敏度高,实用性强,可用于胶粘剂中残余单体的测定。     

低含量点化合物测定的三种数据处理方法比较研究

对于多数定量分析需要绘制标准工作曲线,如果待测化合物的含量过低,靠近工作曲线的最低端则定量分析结果的偏差将较大。本文采用三种数据处理方法进行工作曲线的建立,包括一般线性回归(OLR)、加权线性回归(WLR)和稳健回归(RR)。通过高效液相色谱法对芹菜素含量进行检测,比较了这三种回归方法的准确性。结果表明:对于低含量点化合物而言,WLR较其它两种方法更准确,且处理过程并不复杂,是一种可行、更准确的定量数据处理方法。     

离子色谱法检测马铃薯及其淀粉中氢氰酸

建立了马铃薯及其淀粉中氰化物离子色谱的检测方法。样品经超声、冷冻离心、通过在线过滤处理后直接用离子色谱进行检测。检出限为0.054 mg/L,氰化物的线性范围为0.136～2.72 mg/L;加标回收率为85%～93%;相对标准偏差(RSD)为1.2%,可以满足氰化物检测的要求。