HPLC–ICP–MS法测定农田土壤中甲基汞和乙基汞

采用HPLC反相C18柱分离、ICP–MS检测,建立了农田土壤中甲基汞和乙基汞的分析方法。以0.5mol/L的硝酸溶液为浸提剂,超声波提取1 h,在优化的仪器条件下测定,甲基汞和乙基汞的质量浓度在0.1~50ng/m L范围内与谱线强度呈良好线性关系(r≥0.999),检出限分别为0.1,0.2 ng/m L;加标回收率分别为89.26%~94.26%,76.88%~79.27%;相对标准偏差分别为1.67%~2.38%,2.58%~3.84%(n=5)。该方法样品前处理简单、重现性好、检出限低、准确度高,适合于农田土壤中甲基汞和乙基汞的同时测定。     

顶空气相色谱法测定工作场所空气中的乙酸乙酯

采用顶空气相色谱法测定工作场所空气中的乙酸乙酯。气态乙酸乙酯用活性炭管吸附,二氯甲烷解吸,顶空进样,HP–FFAP毛细管柱分离,FID检测器测定,峰面积定量。乙酸乙酯的质量浓度在1.76~880.0μg/m L范围内与色谱峰面积呈良好的线性,相关系数r=0.999 4。不同浓度样品批内测定结果的相对标准偏差为1.34%~3.61%(n=7),批间测定结果的相对标准偏差为1.04%~4.78%(n=7),加标回收率为91.02%~100.29%,方法检出限为0.32μg/m L,解吸效率为91.28%~95.19%。对于100 mg活性炭,乙酸乙酯的穿透容大于2.2 mg,当其浓度在17.6~17 600 mg/m3时,采样效率为91.23%~97.40%,常温下可以保存10 d。该方法各项指标均达到《工作场所空气中有毒物质检测方法研制规范》的要求,适用于工作场所空气中乙酸乙酯的现场监测。     

Preparation of Janus Graphene Oxide (GO) Nanosheets Based on Electrostatic Assembly of GO Nanosheets and Polystyrene Microspheres

A facile and versatile method for the synthesis of Janus graphene oxide (GO) nanosheets with different structures is reported. Based on electrostatic assembly, Janus GO nanosheets can be easily functionalized with a template polymer or be defunctionalized by altering the ionic strength. By using this approach, Janus GO nanosheets are prepared successfully with hydrophobic polystyrene chains on one side and hydrophilic poly(2‐(dimethylamino)ethyl methacrylate) chains on the other side.

     

由α-氰基肉桂酸乙酯/N-溴代苯甲酰胺合成2-噁唑啉衍生物

作为重要的杂环化合物,合成新的2-噁唑啉衍生物以及发展其新的合成方法具有重要意义,为此以α-氰基肉桂酸乙酯衍生物为底物,以N-溴苯甲酰胺为反应试剂,在无水碳酸钠(相对于底物3为110%摩尔分数)促进下,在丙酮溶剂中,室温下,建立了合成相应2-噁唑啉衍生物的新方法,共合成了11个新化合物,其结构由核磁共振波谱仪(~1H NMR,~(13)C NMR)和高分辨质谱(HRMS)确认。结果显示,各种α-氰基肉桂酸乙酯衍生物(3a~3k)可被顺利的转化成相应的2-噁唑啉衍生物(5a~5k)。在室温下,丙酮作溶剂,以Na_2CO_3为促进剂时,相应产物的最高收率可达90%。不仅α-氰基肉桂酸乙酯衍生物(3)可被用作该反应的底物,而且α-乙氧甲酰基肉桂酸乙酯(6)也适用于该反应。实验结果还证明,除了N-溴代苯甲酰胺外,N-溴代对硝基苯甲酰胺(8)及N-溴代乙酰胺(9)也适用该反应,证明该方法具有广泛的适应性。根据实验结果,提出了可能的反应机理,该机理支持了形成2-噁唑啉衍生物的区域选择性。     

碳纳米管-聚丙烯酸乙酯复合乳液的制备及其润滑性能研究

采用乳液聚合方法合成了碳纳米管一聚丙烯酸乙酯(CNTs—PEA)复合乳液;采用JEM100XI型透射电子显微镜(TEM)观察了复合乳液的微观形貌;采用MQ-800型四球摩擦磨损试验机和MM-200型环一块摩擦磨损试验机考察了CNTs—PEA复合乳液作为水基润滑添加剂的摩擦学性能;并采用JSM-35型扫描电子显微镜(SEM)分析了磨斑表面．结果表明,CNTs—PEA复合乳液在极低浓度下即可有效地提高水基液的承载能力和抗磨性能．     

Experimental validation of an effective carbon number-based approach for the gas chromatography–mass spectrometry quantification of ‘compounds lacking authentic standards or surrogates’

For the quantitative analysis of ‘compounds lacking authentic standards or surrogates’ (CLASS) in environmental media, we previously introduced an effective carbon number (ECN) approach to develop an empirical equation for the prediction of their response factor (RF). In this research, a series of laboratory experiments were carried out to benchmark the reliability of an ECN approach for sorbent tube/thermal desorption/gas chromatography (GC)/mass spectrometry (MS) applications. First, the ECN values were determined using external calibration data from 25 reference volatile organic compounds (VOCs) using two MS dectectors (quadrupole (Q) and time-of-flight (TOF)). Then, a certified standard mixture of 54 VOCs was analyzed by each system as a simulated unknown sample. The analytical bias, assessed in terms of percentage difference (PD) between the certified and ECN-predicted mass values, averaged 19.2 ± 16.1% (TOF-MS) and 28.2 ± 27.6% (Q-MS). The bias using a more simplified carbon number (CN)-based prediction increased considerably, yielding 53.4 ± 53.3% (TOF-MS) and 61.7 ± 81.3% (Q-MS). However, the bias obtained using the ECN-based prediction decreased significantly to yield average PD values of 9.84 ± 7.28% (TOF-MS) and 16.8 ± 8.35% (Q-MS), if the comparison was limited to 26 (out of 54) VOCs with CN ≥ 4 (i.e., 25 aromatics and hexachlorobutadiene).     

Efficient Synthesis of Substituted Indene Derivatives

An efficient protocol for the synthesis of new functionalized indenes 3 was successfully realized. Thus the coupling reaction of allyl acetate 2 with Grignard reagents in the presence of a catalytic amount of LiCuBr₂ at low temperature afforded pure ethyl 1-alkyl-1H-indenes-2-carboxylate 3 in good yields.     

2-氰基-3-取代胺基-3-[2-(4-氟苯基)-乙胺基]丙烯酸乙酯类化合物的合成及生物活性研究

以氰基乙酸乙酯为原料,经与二硫化碳、硫酸二甲酯反应合成了2-氰基-3,3-二甲硫基丙烯酸乙酯(1),然后引入对氟苯乙胺得到化合物(3),其与脂肪胺反应合成了新型含对氟苯乙氨基的2-氰基丙烯酸乙酯类化合物5a～5h,其结构经元素分析,IR1H NMR和13C NMR等确证.初步生物活性试验表明,部分化合物具有一定抗烟草花叶病毒活性.     

凝胶渗透色谱对二次催化溶胶-凝胶法制备硅胶微球过程的监控

采用凝胶渗透色谱法(GPC),通过对二次催化溶胶-凝胶法制备硅胶微球原料硅酸乙酯 40(TES40)、中间产物聚硅酸乙酯(PES)分子量的在线测定,实现了对反应过程的监控.采用Shodex KF-802凝胶色谱柱,以四氢呋喃为流动相,流速0.5 mL/min,柱温40 ℃,采用示差折光检测器检测.校正曲线为1gMw= ...     

Synthesis and Crystal Structure of a Novel Ethyl 5-(4-(2-Phenylacetamido)phenyl)-1H-pyrazole-3-carboxylate as an Acrosin Inhibitor

The title compound (ethyl5-(4-(2-phenylacetamido)phenyl)-1H-pyrazole-3-carboxy- late, C20H19N3O3) was synthesized by the reaction of Claisen condensation, cyclization, reduction and acylation. The structure was characterized by X-ray diffraction, MS, NMR and IR. It belongs to the monoclinic system, space group C2/c with a = 22.723(9), b = 9.324(4), c = 18.890(8) , β = 114.259(6)°, V = 3649(3) 3, Dc = 1.272 Mg·m-3, Z = 8, Mr = 349.38, μ = 0.087 mm-1, F(000) = 1472, the final R = 0.0615 and wR = 0.1643. The biological test shows that the title compound has a moderate acrosin inhibition activity.