气相色谱-质谱法选择离子存储检测模式测定皮革和纺织品中富马酸二甲酯

提出了用气相色谱-质谱法选择离子存储检测模式测定皮革和纺织品中富马酸二甲酯的方法。试样经乙酸乙酯提取后,在40℃真空旋转蒸发器中浓缩至2.0 mL。用乙酸乙酯稀释定容至50 mL,离心后取1 mL上清液过中性氧化铝固相萃取小柱净化,用乙酸乙酯淋洗定容至2 mL,通过VF-5ms色谱柱分离,采用离子阱的选择离子存储检测模式,结合保留时间、特征离子的相对丰度比及谱库检索信息对富马酸二甲酯进行定性检测,用外标法进行定量分析。富马酸二甲酯质量浓度在0.01~50.0 mg.L-1内与峰面积呈线性关系,检出限(3S/N)为0.02 mg.kg-1。用标准加入法做回收试验,测得平均回收率在80%~92%之间,相对标准偏差(n=6)小于5.5%。     

气相色谱-质谱联用法测定包装膜和包装袋中富马酸二甲酯残留量

提出了气相色谱-质谱联用法测定包装膜和包装袋中富马酸二甲酯残留量的方法。样品中富马酸二甲酯用乙酸乙酯萃取,经针式过滤头净化,采用HP-5MS毛细管色谱柱(30 m×0.25 mm,0.25μm)进行分离。采用气相色谱-质谱电子电离源和全扫描监测模式进行测定。富马酸二甲酯的质量浓度在0.5~100.0 mg.L-1浓度范围与其对应的峰面积呈线性关系,测定下限(10S/N)为0.1 mg.kg-1。在5.0,10.0,20.0,30.0,40.0,50.0 mg.kg-16个添加水平下,富马酸二甲酯的回收率在95.0%~102.5%之间,相对标准偏差(n=6)小于6%。     

气相色谱-质谱法测定家具及纺织品中富马酸酯类防腐剂

提出了气相色谱法测定家具和纺织品中富马酸二甲酯、富马酸二乙酯、富马酸单乙酯3种防腐剂。样品用乙酸乙酯超声提取后,30℃旋转蒸发器中浓缩至2 mL。用乙酸乙酯稀释定容至5.0 mL,通过DB-FFAP色谱柱分离,采用选择离子监测模式进行测定。富马酸二甲酯和富马酸二乙酯的的线性范围为0.05~5.00 mg.L-1、富马酸单乙酯的的线性范围为0.10~10.0 mg.L-1,测定下限(10S/N)依次为0.01,0.01,0.02 mg.kg-1。以家具和纺织品样品为基体,在3个浓度水平下进行回收试验,3种防腐剂的回收率均大于80%,相对标准偏差(n=6)均小于5.0%。     

气相色谱-质谱法测定食品接触材料聚对苯二甲酸乙二醇酯塑料中间苯二甲基异氰酸酯的残留量北大核心CSCD

采用气相色谱-质谱法测定食品接触材料聚对苯二甲酸乙二醇酯塑料中间苯二甲基异氰酸酯的残留量。样品1.000g经5 mL乙酸乙酯超声提取25 min,上清液用乙酸乙酯定容至10mL后,经0.45μm有机系微孔滤膜过滤。在气相色谱分离中采用HP-5MS石英毛细管色谱柱,在质谱分析中采用全扫描和选择离子监测模式。间苯二甲基异氰酸酯的质量浓度在0.05～5.0mg·L^(-1)内与其对应的峰面积呈线性关系,测定下限(10S/N)为0.05mg·kg^(-1)。以空白样品为基体进行加标回收试验,所得回收率为79.2%～93.4%,测定值的相对标准偏差(n=7)为0.83%～4.5%。     

固相萃取-气相色谱-质谱法同时测定植物油中7种邻苯二甲酸酯

采用气相色谱-质谱法测定植物油中7种邻苯二甲酸酯类增塑剂的含量。样品用正己烷溶解后,经Cleanert PAE固相萃取柱净化,采用正己烷-乙酸乙酯(1+1)混合溶液洗脱,洗脱液用氮气吹至近干,乙腈定容后,在DB-5毛细管色谱柱上分离,质谱中选择电子轰击离子源-选择离子监测模式。7种邻苯二甲酸酯的质量浓度在0.1~5.0 mg·L-1范围内呈线性,检出限(3S/N)为0.02 mg·kg-1。加标回收率在80.0%~120%之间,测定值的相对标准偏差(n=6)在1.1%~5.4%之间。     

气相色谱-串联质谱法测定皮革和纺织品中的富马酸二甲酯

建立了气相色谱-串联质谱(GC-MS/MS)准确、快速测定皮革和纺织品中富马酸二甲酯(DMF)的分析方法。样品经乙酸乙酯提取、浓缩及固相萃取柱净化处理,通过VF-5ms色谱柱分离、串联质谱对DMF进行定性和定量分析。实验结果表明: 优化样品预处理条件、固相萃取条件、质谱分析条件后,该方法可进一步消除杂质干扰,结果准确可靠,灵敏度、精密度、线性关系良好,回收率较高。3种浓度水平的加标回收率(n=6)保持在84%～93%之间,相对标准偏差小于7.2%;DMF在8种皮革和纺织品中的检出限 (S/N=3)为0.012～0.039 mg/kg, 0.05～100 mg/L质量浓度范围内线性相关系数为0.9990,适用于皮革和纺织品中DMF的日常检测。     

糕点中富马酸二甲酯的毛细管气相色谱快速测定

建立了糕点中富马酸二甲酯的毛细管气相色谱快速检测方法.富马酸二甲酯易溶于三氯甲烷,通过超声波提取,用三氯甲烷提取糕点中的富马酸二甲酯,用毛细管气相色谱测定.方法的最低检出限为2.00mg/kg,标准曲线的线性范围:10～500μg/mL,相关系数r为0.999 99,样品加标回收率为93.0%～109.0%,相对标准偏差RSD为1.30%～1.90%.结果表明方法操作简便、快速、回收率高、精密度好,可用于糕点中富马酸二甲酯含量的快速测定.     

快速溶剂萃取-气相色谱-串联质谱法测定血中12种催眠类药物

提出了气相色谱-串联质谱法测定血液中12种催眠类药物含量的方法。样品以乙酸乙酯-环己烷-丙酮(2+2+1)混合液为萃取剂,使用氧化铝吸附剂达到在线净化的效果,经快速溶剂萃取仪提取后,提取液用氮气吹干,用甲醇0.5mL溶解,通过VF-5MS色谱柱分离,采用电子轰击离子源多反应监测模式进行测定。12种催眠类药物的质量浓度与其峰面积均在50.0~1 000μg·L-1之间呈线性关系,测定下限(10S/N)在0.02~4.7μg·L-1之间。加标回收率在65.4%~98.2%之间,测定值的相对标准偏差在0.9%~14.8%之间。     

气相色谱-质谱法测定陈皮及其制品中的三氯杀螨醇和拟除虫菊酯残留量

样品2.000 0g,加水2mL或4mL浸润,再加入乙酸乙酯-正己烷(1+1)混合液5mL,超声5min,提取2次。合并的提取液吹干,残渣用乙酸乙酯-正己烷(1+1)混合液2mL溶解,经被氧化的改性多壁碳纳米管净化后,其中的三氯杀螨醇和8种拟除虫菊酯农药采用气相色谱-质谱法测定。以Rtx-1701毛细管色谱柱为固定相进行气相色谱分离。质谱分析中采用选择离子监测模式,外标法定量。9种农药的质量浓度在0.010~1.0mg·L~(-1)内与其峰面积呈线性关系,检出限(3S/N)在3.5~6.0μg·kg~(-1)之间。按标准加入法在3个浓度水平上进行回收试验,回收率在84.8%~105%之间,测定值的相对标准偏差(n=6)在3.1%~8.2%之间。     

高效液相色谱法测定海洋涂料中敌草隆和吡啶硫酮铜

提出了高效液相色谱法同时测定海洋涂料中的敌草隆和吡啶硫酮铜含量的方法。海洋涂料样品(0.020 0g)用乙酸乙酯(10mL)超声提取10min。分取1.0mL上清液,加入1mL乙腈混匀后进行色谱分离。以Agilent ZORBAX Eclipse XDB-C18色谱柱为固定相,用乙腈和水以不同比例混合的溶液为流动相进行梯度洗脱,用二极管阵列检测器测定。敌草隆和吡啶硫酮铜的线性范围分别为0.15~800,0.20~200 mg·L-1,检出限(3S/N)为8.0 mg·kg-1(敌草隆)和12.0mg·kg-1(吡啶硫酮铜)。以空白样品为基体在3个浓度水平上进行加标回收试验,所得回收率在90.0%~95.0%之间,测定值的相对标准偏差(n=6)在1.7%~3.4%之间。     

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%.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

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.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

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.     

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.