大一学生化学实验室安全基础知识调查研究*

为考察大一学生化学实验室安全基础知识,对天津理工大学化学化工学院大一学生警示标识、危险化学品性质、废弃物处理及意外处置等安全知识进行问卷调查。结果表明:60.4%的学生将易燃标识与氧化剂标识混淆;在危险化学品性质和酸/碱撒漏处理方面有待加强。基于以上结果,在后续安全教育过程中,普及GHS标识及MSDS,对相关知识进行针对性的查漏补缺;充分利用线上资源,弥补线下教育因时间有限、容量有限导致的不足。     

Identification and Quantification of Polar Nitroaromatic Compounds in Explosive-Contaminated Waters by means of HPLC-ESI-MS-MS and HPLC-UV

In the area of former ammunition plants, contaminations caused by explosives and their degradation products are of great environmental relevance because of the immediate vicinity of ground- and drinking water reservoirs. Beside the determination of selected explosive-related compounds by means of HPLC with UV detection, a LC-MS-MS coupling utilizing electrospray ionisation was developed, which is particularly suited for the determination of highly polar compounds. Therewith, 12 different explosive-related compounds were identified and quantified on the basis of specific precursor-/ product-ion traces using the high selectivity and sensitivity of multiple reaction monitoring mode (MRM) of a triple quadrupole mass spectrometer. The LC-MS-MS-technique was applied to water samples from the area of a former ammunition plant. In addition to dinitrophenols and aminodinitrotoluenes which could be determined also by HPLC-UV, some highly polar compounds were found in the contaminated water, for example 3,5-dinitrobenzoic acid and 2-amino-4,6-dinitrobenzoic acid. The highest concentrations (14–40 μg L⁻¹) were found for two isomers of dinitrotoluenesulfonic acids. In order to assure the quantitative determination of polar substances in real samples with different composition, external calibration and standard addition method were compared. The presented LC-MS-MS-method is suited for screening and quantification of polar and hydrophilic explosive-related compounds from different classes of substances in a single analytical protocol.     

<Emphasis Type="Italic">In-silico</Emphasis> Screening using Flexible Ligand Binding Pockets: A Molecular Dynamics-based Approach

Summary In-silico screening of flexible ligands against flexible ligand binding pockets (LBP) is an emerging approach in structure-based drug discovery. Here, we describe a molecular dynamics (MD) based docking approach to investigate the influence on the high-throughput in-silico screening of small molecules against flexible ligand binding pockets. In our approach, an ensemble of 51 energetically favorable structures of the LBP of human estrogen receptor α (hERα) were collected from 3 ns MD simulations. In-silico screening of 3500 endocrine disrupting compounds against these flexible ligand binding pockets resulted in thousands of ER–ligand complexes of which 582 compounds were unique. Detailed analysis of MD generated structures showed that only 17 of the LBP residues significantly contribute to the overall binding pocket flexibility. Using the flexible LBP conformations generated, we have identified 32 compounds that bind better to the flexible ligand-binding pockets compared to the crystal structure. These compounds, though chemically divergent, are structurally similar to the natural hormone. Our MD-based approach in conjunction with grid–based distributed computing could be applied routinely for in-silico screening of large databases against any given target.     

浅谈同煤集团环境监测站化学危险品的安全管理

介绍了化学危险品的危险特性以及实验室储存和使用中应注意的问题,通过分析,对实验室的管理和检测人员提出了工作中避免事故发生的要求.     

TG Evolved Gas Analysis Using ATD Sample Tubes

A new variation of off-line TG evolved gas analysis is reported here. Gas collection is done by inserting sample tubes filled with a suitable adsorbent, into the exhaust from the TG instrument. The following gas analysis is carried out by placing the sample tubes into a commercial thermal desorption unit which is coupled to a GC/MS. In this way, both a chromatographic separation of components as well as a mass spectral identification are obtained. Two examples from the analysis of production chemicals demonstrate the usefulness of this approach. This revised version was published online in July 2006 with corrections to the Cover Date.     

Catalytic applications of hydrotalcite-like materials and their derived forms

Hydrotalcite-like (HT-like) materials have been studied extensively in the last three decades. Although these materials initially perceived as potential anion exchangers, unrelenting efforts have also been attempted to use them as catalytic materials or as catalytic supports. There are varied ways by which one can use them for catalysis viz.; 1. Use them in as-synthesized form 2. Use them after calcining where the structural integrity of layered lattice is lost 3. Use the interlayer as functional spaces with moieties of catalytic interest 4. Use them after destruction or delamination and restructuring and 5. Use them as support or matrix. In this review, we are reporting the catalytic applications of HT-like materials and their derived forms carried out in our research group for the last 15 years in these various ways, covering reactions such as nitrous oxide decomposition, selective oxidation of organic compounds of industrial relevance and base-catalyzed isomerization of chemicals of perfumery interest. Although this review primarily focuses on our work, wherever applicable, related or relevant works from other groups are also presented to bestow comprehensiveness.     

Does bisphenol A bioaccumulate on zebrafish? Determination of tissue bisphenol A level

Bisphenol A (BPA) is a high-production-volume industrial chemical mainly used in the production of polycarbonates and epoxy resins utilized in the manufacture of containers, bottles, toys, and medical devices. It has systemic effects as an endocrine disruptor even at low doses. To analyze its quantity in biological materials, sensitive and reproducible methods have to be used. Different doses and duration (90 and 900 μg/L, 24 and 120 h, and 21 days) of BPA exposure to whole body zebrafish were analyzed after specific homogenization of tissue, and then a modified method HPLC was used. The mobile phase was acetonitrile and water using a gradient method of reversed-phase C18 column, and excitation = 227 nm/emission = 313 nm. The calibration curve for BPA using HPLC-fluorescence detection method was between a concentration range of 1 and 1000 ng/mL and linear, and r² = 0.999. The mean and standard error of mean values were 4.29 ± 1.05, 2.50 ± 0.92, and 2.53 ± 0.68 for control; 10.43 ± 2.61, 11.46 ± 3.24, and 8.55 ± 3.11 for BPA-90 μg/L; and 17.78 ± 4.39, 21.55 ± 4.37, and 25.32 ± 3.25 for BPA-900 μg/L (24 h, 120 h, and 21 days, respectively). Although some statistical significance among dose/time was observed between two different dose-treated groups, statistical significance was not found in dose/time results within the group. However, the positive result of BPA in the control group can be explained by low-dose, chronic exposure or prevalence of endocrine-disrupting chemicals.     

Integration of zeolite@metal–organic framework: a composite catalyst for isopropyl alcohol conversion to aromatics

In this study, a Zn-based metal-organic framework (MOF)-zeolite composite ZSM-5@IRMOF-1 was synthesized for the alternative production of BTX from isopropyl alcohol (IPA). Incorporation ensured the capacity to tune the Lewis acidity at a framework level and design accessible pore structures, making composites highly attractive to be used as catalysts. The combination of monodispersed HZSM-5 zeolites on and within acidic IRMOF-1 provided the highly selective production of lower aromatics from IPA. The interaction of IPA with catalysts was investigated at different temperatures in a fixed-bed continuous flow reactor. The obtained product was analyzed using a standard test method ASTM D6730 through gas chromatography-detail hydrocarbon analyser. The results indicated that the reaction between IPA and MOF-supported zeolite occurred without substantial participation of MOFs. The maximum aromatic (BTEX) selectivity of 38.2% was achieved among all hydrocarbons at 92.3% carbon conversion. In addition, the gas yield was <20% for this catalyst system. The appropriate density of Brønsted and Lewis acidic sites and hierarchical pore structures provided the composite catalyst with outstanding aromatic selectivity yield and high stability.     

Detection of multiple endocrine-disrupting chemicals in milk: Improved and safe high performance liquid chromatography tandem mass spectrometry method

Herein, an improved method for detecting the endocrine-disrupting chemicals in milk is presented, which is based on high performance liquid chromatography tandem mass spectrometry, coupled with a quick, effective, and safe method. The linearity of the proposed method was in the range of 0.05–100 μg/L, and all correlation coefficients were ≥0.9973. At three concentration levels, the spiked recoveries ranged from 77.7 to 107.5%, relative standard deviations ranged from 0.2 to 14.6%, limits of quantitation ranged from 0.1 to 40 μg/kg, limits of detection ranged from 0.03 to 13.3 μg/kg. The proposed method for the identification and quantitation of 26 endocrine disruptors present in milk is not only easy, fast, and cost-efficient but also provides a reference for the detection of various endocrine disruptors in milk and other dairy products.