双酚A分子印迹材料的制备及其识别特性研究

以双酚A为模板分子,α-甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,偶氮二异丁腈为引发剂制备了双酚A印迹聚合物。采用动态和静态两种方法研究了该印迹材料对双酚A的结合性能与分子识别特性。印迹材料对模板分子双酚A具有良好的特异性识别作用,经过Scatchard模型分析,双酚A印迹聚合物上有两类不同性质的结合位点,两种结合位点的解离常数分别为1.36和44.78 m L/g,对双酚A的最大表观吸附量分别为24.56μmol/g和312.6μmol/g。将该聚合物应用于固相萃取中,以食品包装材料为样品的加标回收实验表明,此印迹材料可以对痕量双酚A进行富集分离测定,且可重复使用。     

液相色谱-串联质谱法同时测定纺织品和食品包装材料中的壬基酚、辛基酚和双酚A

建立了纺织品和食品包装材料中壬基酚、辛基酚和双酚A的液相色谱-串联质谱分析方法。不同类型的纺织品和食品包装材料样品采用加速溶剂萃取法,以无水乙醇为提取剂,在10.3 MPa和120℃下静态循环提取2次,提取液经Supelclean Envi-Carb石墨化碳黑固相萃取柱净化,收集甲醇-二氯甲烷(1∶4,V/V)洗脱液,采用Waters XBridge C18色谱柱,以甲醇-0.1%氨水溶液为流动相,梯度洗脱分离后,在LC/MS/MS多反应监测模式下进行定性与定量分析。壬基酚、辛基酚和双酚A的方法检出限为0.5μg/kg,在0.5～10μg/kg的3个添加水平范围内,纺织品样品的平均回收率为86.9%～92.5%,相对标准偏差均小于9.1%;食品包装材料样品的平均回收率为87.8%～93.0%,相对标准偏差均小于8.8%。本方法准确、快速、灵敏度高,可用于纺织品和食品包装材料的实际检验。     

荧光法测定食品包装材料中的双酚A

建立了用β-环糊精包被双酚A,使荧光强度增强,从而定量检测食品包装材料中双酚A含量的方法。在pH=4,波长λex／λem=282／318nm时,检出限为0．2μg／L,线性范围为1—10μg／L,回收率为98％～102％。本法检测灵敏、准确、快速简便。     

液相色谱-三重四极杆质谱同时测定食品接触材料中双酚A、双酚F与双酚S的迁移量

采用液相色谱-三重四极杆质谱(LC-MS/MS)建立了食品接触材料中双酚A、双酚F和双酚S化合物的同时测定方法。双酚A、双酚F和双酚S在样品中通过与食品模拟物在一定温度、时间接触的状态下迁移到食品模拟物中,以C18色谱柱进行分离,甲醇-氨水为流动相洗脱,采用电喷雾离子源(ESI),多反应监测(MRM)负离子模式进行扫描,同位素内标法定量。结果表明,双酚A、双酚F和双酚S的色谱分离良好,双酚A和双酚F在1~50μg/L质量浓度范围内与其峰面积均呈线性关系,BPS在0.1~50μg/L质量浓度范围内与其峰面积呈线性关系。BPA和BPF的最低检出限为0.3μg/L,BPS的最低检出限为0.05μg/L。加标回收率为83.6%~102.6%,相对标准偏差(RSD)为3.5%~8.9%。该方法快速可靠、准确简便,适用于食品接触材料中双酚A、双酚F和双酚S化合物的检测。     

化学计量学优化-分散液液微萃取-荧光分析法测定食品接触物中双酚A的迁移量

建立了分散液液微萃取-荧光分析法测定双酚A的方法,并对塑料水杯和塑料袋中双酚A的迁移量进行测定。经Plackett-Burman设计筛选影响因素后,利用中心复合表面设计确定了最佳萃取条件。利用全因子设计确定荧光测定条件为:0.2 mol/L HCl,4×10-4mol/Lβ-环糊精。在水、10%乙醇条件下,方法线性范围1～50μg/L(r=0.999),检出限为0.53μg/L;在3%乙酸条件下,线性范围为1～60μg/L(r=0.997),检出限为0.85μg/L。方法回收率为95.4%～111.2%,相对标准偏差(n=6)为13%～16%。所测样品在室温水中双酚A迁移量低于检出限,在沸水、3%乙酸及10%乙醇中均有不同程度迁移。     

固相萃取/超高效液相色谱-串联质谱法测定尿液中6种双酚类及烷基酚类物质

建立了超高效液相色谱-串联质谱测定人体尿液中双酚A(BPA)、双酚F(BPF)、四氯双酚A(TCBPA)、四溴双酚A(TBBPA)、壬基酚(NP)、4-正辛基苯酚(4-n-OP)的检测方法。尿液样品通过酶解和固相萃取法进行前处理,采用Acquity UPLC HSS T3色谱柱(2.1 mm×100 mm,1.8μm)分离,负离子电喷雾多反应监测模式检测,同位素内标法定量。6种待测物在0.5~50μg/L范围内线性关系良好,相关系数均大于0.995,检出限为0.05~0.60μg/L,定量下限为0.17~2.00μg/L,2、10、50μg/L加标水平下的回收率为81.4%~112%,相对标准偏差(RSD,n=6)为6.8%~30%。应用此方法测定160份人体尿液样品,双酚A的检出率为93.8%,检出范围为0.24~29.54μg/L,其余目标物未检出。该方法操作简便、重现性好、定量准确,适用于人体尿液中双酚类及烷基酚类物质的测定。     

高效液相色谱法对纺织品和食品包装材料中的壬基酚、辛基酚和双酚A的同时测定

建立了高效液相色谱-二极管阵列检测器(DAD)/荧光检测器(FLD)串联技术同时测定纺织品和食品包装材料中壬基酚、辛基酚和双酚A的方法.实验样品采用加速溶剂萃取法,以无水乙醇为提取溶剂,在10.3 MPa和120 ℃下静态循环提取2次,提取液经Supelclean Envi-Carb石墨化碳黑固相萃取柱净化,以Agilent Zorbax SB-Phenyl(250 mm×4.6 mm,5 μm)色谱柱分离后用DAD-FLD串联法进行检测.壬基酚、辛基酚和双酚A的DAD检测波长为225 nm;荧光激发波长为227 nm,发射波长为315 nm.在25、50、500 μg/kg的添加水平下,纺织品样品和食品包装材料样品的平均回收率均为93% ～98%,相对标准偏差分别为2.8% ～7.0%和2.9% ～6.9%.方法准确、简便、快速,可用于纺织品和食品包装材料的实际检验工作.     

单扫示波极谱法测定食品包装材料中双酚A的研究

研究发现，在0.12mol/L Na2HPO4-KH2PO4(pH7.5)底液中，双酚A于峰电位（Ep)-1.0V(vs.SCE)处产生灵敏的极谱还原波，该波的二阶导数峰电流（ip)与双酚A浓度在2.0-10.0mg/L范围内呈良好的线性关系，检出限为1.0mg/L，萃取后测定，检出限为0.1mg/L。本法操作简便、快速、准确。用于食品包装材料中双酚A含量的测定，结果令人满意。     

三相中空纤维膜液相微萃取-高效液相色谱法测定水中痕量双酚A

建立了三相中空纤维膜液相微萃取-高效液相色谱(HF-LPME-HPLC)方法,用于分析测定水中痕量双酚A的含量.设计了三相中空纤维膜液相微萃取系统,优化的HP-LPME最佳萃取条件为:萃取剂为正辛醇,接受相NaOH浓度为0.09 mol/L,样品溶液pH=4.0,NaC1加入量为30 g/L,搅拌速度为900 r/min,萃取时间为60 min.萃取后取20 μL接受相进行色谱分析.在最佳萃取条件下,方法的线性范围为0.5～200 μg/L(r＞ 0.999),检出限(信噪比为3)为0.2 μg/L;富集因子为241;方法RSD＜3.2％ (n=3).在实际环境水样中添加5,20和50μg/L的双酚A标准物质,加标平均回收率为92.8％～101.9％.表明本方法可用于水中痕量双酚A的快速准确测定.     

高效液相色谱-串联质谱法测定食品包装材料中全氟辛烷磺酰基化合物(PFOS)

建立了用高效液相色谱-串联质谱(HPLC/MS/MS)结合快速溶剂萃取测定食品包装材料中全氟辛烷磺酰基化合物(PFOS)的方法。采用乙腈溶剂,快速溶剂提取食品包装材料中的PFOS,提取液经0.2μm有机滤膜过滤后,以V(乙腈)∶V(10 mmol/L乙酸铵溶液)=80∶20为流动相,经HPLC分离后用多级反应监测(MRM)方式测定。用两个子离子的相对丰度定性,外标法定量。PFOS在0.002~0.1μg/mL范围内线性良好(R2=0.998),回收率为93.8%~101%,精密度RSD为1.6%~3.1%,方法检出限为0.4μg/m2(S/N≥10),满足欧盟法规对食品包装材料中PFOS的限量检测要求。方法可用于食品包装材料中PFOS的检测。     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Copper catalyzed/mediated synthetic methodology for ebselen and related isoselenazolones

Scope of the copper catalyzed/mediated selenium-nitrogen coupling reaction has been studied for the synthesis of isoselenazolones. It is noticed that the 2-chloro, 2-bromo-, and 2-iodo-aryl amides substrates can be exploited in the selenium-nitrogen coupling reaction by employing 25-100 mol % of CuI/1,10-phenanthroline (L) and potassium carbonate as a base in DMF. Furthermore, electron rich 2-chloro-arylamides also underwent selenium-nitrogen coupling reaction to give biologically important selenium-nitrogen heterocycles. Also, copper-catalyzed selenium-nitrogen coupling reaction has been meticulously applied for the synthesis of diaryl diselenides having methoxy, amine, and amide functionality from respective aryl iodides in the presence of stoichiometric amount of succinimide as an external Se-N coupling partner.