加速溶剂萃取-气相色谱-质谱法测定塑料中7种有机磷酸酯阻燃剂和增塑剂

建立了一种加速溶剂萃取-气相色谱-质谱法测定塑料中三-(2-氯乙基)磷酸酯(TCEP)、三-(2-氯丙基)磷酸酯(TCPP)、三-(2,3-二氯丙基)磷酸酯(TDCP)、磷酸三苯酯(TPh P)、三-(邻甲苯基)磷酸酯(To CP)、三-(间甲苯基)磷酸酯(Tm CP)和三-(对甲苯基)磷酸酯(Tp CP)7种有机磷酸酯阻燃剂和增塑剂的分析方法。以甲苯为溶剂,采用加速溶剂萃取方式提取样品中7种有机磷酸酯阻燃剂和增塑剂,外标法定量,GC-MS分析。TCEP,TCPP,TDCP,TPh P,To CP,Tm CP和Tp CP的线性范围均为0.5~10 mg/L(R2≥0.998),检出限(S/N3)分别为0.1,0.035,0.045,0.1,0.1,0.1和0.1 mg/kg。塑料制品中TCEP,TCPP,TDCP,TPh P,To CP,Tm CP和Tp CP在3个添加浓度水平的加标回收率范围在85.4%~110.6%;相对标准偏差(RSD,n=5)小于5.0%。方法已应用于塑料制品中上述7种有机磷酸酯阻燃剂和增塑剂的测定。     

气相色谱-质谱法测定聚氨酯泡沫中3种阻燃剂

提出了气相色谱-质谱法测定聚氨酯泡沫中的三(1,3-二氯异丙基)磷酸酯、三(2-氯乙基)磷酸酯和三(2-氯丙基)磷酸酯等3种阻燃剂含量的方法。聚氨酯泡沫样品用丙酮进行索氏抽提,在气相色谱分离中用HP-5MS毛细管柱为固定相,在质谱分析中采用选择离子监测模式。3种阻燃剂在一定的质量浓度范围内与其峰面积呈线性关系,方法的检出限(3S/N)在0.4~1.5mg·kg-1之间,测定下限(10S/N)在1.3~5.0mg·kg-1之间。以空白样品为基体进行加标回收试验,所得回收率在84.2%~93.6%之间,测定值的相对标准偏差(n=6)在0.62%~3.3%之间。     

气相色谱-质谱法测定塑料中7种有机磷酸酯阻燃剂的含量

样品0.100 0 g置于微波萃取管中,加入乙腈15 mL,涡流振荡2 min,微波萃取20 min,冷却至室温后,收集上清液。再加入乙腈10 mL涡流振荡2 min,合并上清液。所得萃取液蒸发至近干,再用氮气吹干,用10 mL丙酮稀释。以DB-5MS色谱柱为固定相,采用气相色谱-质谱法测定上述溶液中三(2-氯乙基)磷酸酯、三(1,3-二氯丙基)磷酸酯、三(2-氯异丙基)磷酸酯、磷酸三苯酯、磷酸三对甲苯酯、磷酸三间甲苯酯和磷酸三邻甲苯酯等7种有机磷酸酯阻燃剂的含量。质谱分析中采用选择离子监测(SIM)模式。7种有机磷酸酯阻燃剂的线性范围均为1.00~100 mg·L~(-1),测定下限(10S/N)为0.28~1.00 mg·L~(-1)。按标准加入法进行回收试验,回收率在85.9%~95.2%之间,相对标准偏差(n=9)均小于8.0%。     

气相色谱-质谱法测定塑料中7种有机磷酸酯阻燃剂的含量北大核心CSCD

样品0.100 0 g置于微波萃取管中,加入乙腈15 mL,涡流振荡2 min,微波萃取20 min,冷却至室温后,收集上清液。再加入乙腈10 mL涡流振荡2 min,合并上清液。所得萃取液蒸发至近干,再用氮气吹干,用10 mL丙酮稀释。以DB-5MS色谱柱为固定相,采用气相色谱-质谱法测定上述溶液中三(2-氯乙基)磷酸酯、三(1,3-二氯丙基)磷酸酯、三(2-氯异丙基)磷酸酯、磷酸三苯酯、磷酸三对甲苯酯、磷酸三间甲苯酯和磷酸三邻甲苯酯等7种有机磷酸酯阻燃剂的含量。质谱分析中采用选择离子监测(SIM)模式。7种有机磷酸酯阻燃剂的线性范围均为1.00~100 mg·L^(-1),测定下限(10S/N)为0.28~1.00 mg·L^(-1)。按标准加入法进行回收试验,回收率在85.9%~95.2%之间,相对标准偏差(n=9)均小于8.0%。     

GC–MS法测定塑料及其制品中三(2-氯乙基)磷酸酯

采用气相色谱–质谱联用法检测塑料及其制品中阻燃剂三(2-氯乙基)磷酸酯的含量。样品采用微波萃取,萃取温度为100℃,时间为10 min,浓缩样品溶液至近干后定容至1 m L,用0.45μm滤膜过滤,采用气相色谱–质谱联用仪进行定性定量分析。三(2-氯乙基)磷酸酯的质量浓度在0.1~10.0μg/mL范围内与色谱峰面积呈良好的线性,线性相关系数为0.999 8,检出限为0.02 mg/kg。空白样品加标回收率为85.1%~94.6%,测定结果的相对标准偏差在1.60%~4.15%(n=7)之间。该方法准确度高,重现性好,可作为塑料及其制品中三(2-氯乙基)磷酸酯的检测方法。     

控温超声提取-气相色谱-三重四级杆质谱测定大气细颗粒物(PM2.5)中的多环芳烃

建立了控温超声提取-气相色谱三重四级杆质谱测定大气细颗粒物(PM2.5)中多环芳烃(Polycyclic aromatic hydrocarbon,PAHs)的分析方法。PM2.5中的PAHs用二氯甲烷-正己烷(2∶1,V/V)控温超声提取3次,每次提取20 min,气相色谱-串联质谱分析,得到16种PAHs和6种替代物的标准曲线线性关系良好,相关系数均大于0.99,16种PAHs的检出限范围为0.013~0.12μg/L。实验中还观察到PAHs在空白滤膜中有微量存在,回收率实验中得到6种替代物的回收率在58.7%~108.2%之间,16种PAHs的空白滤膜加标的平均回收率在88.3%~104.0%之间,相对标准偏差均低于9.0%,实际滤膜加标的平均回收率在77.3%~98.7%之间,相对标准偏差均低于6.0%,本方法能够满足实际大气样品的测定。     

同时加速溶剂萃取/气相色谱-质谱法测定植物中13种有机磷酸酯

建立了同时加速溶剂萃取和净化、气相色谱-离子阱二级质谱检测植物中13种有机磷酸酯阻燃剂/增塑剂的分析方法。样品放入以硅胶和活性炭作为在线净化填料的萃取池中,在萃取溶剂为正己烷-丙酮(1∶1,体积比)、萃取温度100℃、静态萃取时间10 min、循环2次的条件下进行加速溶剂萃取,萃取液浓缩后经DB-5MS(30 m×0.25 mm×0.25μm)气相色谱柱分离,选择反应监测模式(SRM)检测,以保留时间和特征离子对定性,内标法定量。结果表明,该方法具有较好的准确度和精密度,13种有机磷酸酯在3个加标水平下的回收率为76.9%~113.0%,相对标准偏差为2.0%~14.6%,方法检出限为0.79~2.27 ng/g,方法定量下限为2.65~7.59 ng/g。该方法简便、快速、准确,可用于植物中13种有机磷酸酯的测定。     

预浓缩-气相色谱-质谱法测定大气中34种挥发性有机物含量

采用预浓缩-气相色谱-质谱法测定大气中34种挥发性有机物的含量。采用苏玛罐采集大气样品,通过预浓缩系统富集浓缩,在气相色谱分离中用DB-624色谱柱为固定相,在质谱分析中采用全扫描模式。34种挥发性有机物的线性范围均为0.5~40nL·L-1,方法的检出限在0.01~0.14μg·m-3之间。回收率在86.7%~98.7%之间,测定值的相对标准偏差(n=6)在2.5%~8.6%之间。     

同位素内标-气相色谱-质谱联用法测定食品接触材料中的有机磷酸酯

建立了同位素内标-气相色谱-质谱(GC-MS)联用法测定食品接触材料中3种有机磷酸酯含量。样品中加入3种有机磷酸酯对应的同位素标记物,以丙酮作提取剂超声提取,采用优化后的GC-MS条件进行分析,以同位素为内标,在选择离子监测(SIM)模式下进行定量分析。结果表明,3种有机磷酸酯在0.0005～50 mg/L浓度范围内线性关系良好,相关系数r均大于0.999,方法检出限(LODs)为0.0017～0.039 mg/kg,定量限(LOQs)为0.0057～0.13 mg/kg,回收率在87.9%～113.0%,相对标准偏差在2.4%～7.8%之间。该方法样品前处理简单,灵敏度、准确度高,可用于食品接触材料中有机磷酸酯的日常检测。     

固相萃取-气相色谱/质谱联用法测定儿童手推车中3种有机磷酸酯阻燃剂

有机磷酸酯是一类重要的磷系阻燃剂,由于其具有类似持久性有机污染物(persistent organic pollutants, POPs)的性质,欧美等国家已纷纷设立相关法规限制其在儿童用品中的使用。目前国际和国内均未有儿童手推车中有机磷酸酯阻燃剂的检测标准。本文建立了儿童手推车中3种有机磷酸酯阻燃剂的超声萃取-弗罗里硅土固相萃取柱净化-气相色谱/质谱检测方法。该方法的加标回收率为89.5%~107.3%,检出限(3S/N)为0.01 mg/kg,定量限(10S/N)为0.1 mg/kg,能较好地排除基质干扰,适用于儿童手推车软垫材料中3种有机磷酸酯的定性和定量分析。37个样品的分析结果表明,磷酸三(2-氯丙基)酯(TCPP)的检出率为81.1%,含量范围为1.0~15312.8 mg/kg,依据欧盟玩具新指令2014/79/EU, TCPP超标(> 5 mg/kg)率为32.4%;其中2个样品中还检出了磷酸三(2-氯乙基)酯(TCEP)和磷酸三(1,3-二氯-2-丙基)酯(TDCP),含量范围为6.2~44.1 mg/kg,均已超标。可见,市场上的儿童手推车存在较高的有机磷酸酯阻燃剂暴露风险。     

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.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.