同位素稀释-气相色谱-质谱法测定白酒中23种邻苯二甲酸酯类化合物

提出了同位素稀释-气相色谱-质谱法测定白酒中23种邻苯二甲酸酯类化合物含量的方法。样品用正己烷-乙酸乙酯(1+1)混合液提取后,经DB-5MS毛细管色谱柱分离,采用电子轰击离子源选择离子反应监测模式进行质谱测定,同位素内标法进行定量分析。23种邻苯二甲酸酯类化合物的线性范围在0.2~3.0mg·L-1之间,测定下限(10S/N)在0.05~0.1mg·kg-1之间。加标回收率在73.2%~122%之间,相对标准偏差(n=6)在0.49%~11%之间。     

气相色谱-串联质谱法测定生态纺织品中的邻苯二甲酸酯类

采用气相色谱-串联质谱法同时测定生态纺织品中的24种邻苯二甲酸酯类。样品经正己烷超声提取,提取液经ProElut PSX玻璃固相萃取柱净化,以丙酮-正己烷(15+85)混合液洗脱,洗脱液经氮气吹至近干后,用正己烷定容至1.0 mL。采用DB-5MS毛细管色谱柱分离,质谱分析中采用电子轰击离子源和选择反应监测模式。24种邻苯二甲酸酯类的质量浓度在一定范围内与峰面积呈线性关系,检出限(3S/N)在1.0~10 mg·kg~(-1)之间,测定下限(10S/N)在5.0~25 mg·kg~(-1)之间。加标回收率在81.3%~102%之间,测定值的相对标准偏差(n=6)在1.8%~6.6%之间。     

层析净化-气相色谱-质谱法测定烟叶中6种邻苯二甲酸酯

采用层析净化-气相色谱-质谱法测定烟叶中6种邻苯二甲酸酯的含量。烟叶样品经正己烷-丙酮(1+1)溶液超声提取,过硅胶层析柱,以正己烷-丙酮(9+1)混合液洗脱净化,在气相色谱分离中用DB-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。6种邻苯二甲酸酯的质量浓度均在0.02~10.0mg·L~(-1)范围内与其峰面积呈线性关系。方法用于烟叶样品分析,加标回收率在81.6%~107%之间,测定值的相对标准偏差(n=6)在3.2%~9.8%之间。     

气相色谱-质谱法测定酒中23种邻苯二甲酸酯残留量

应用气相色谱-质谱法测定酒中23种邻苯二甲酸酯残留量。样品在沸水浴中加热除去乙醇后用正己烷提取。离心分离后上清液经DB-5MS石英毛细管色谱柱分离,在选择离子检测模式下进行质谱测定。23种邻苯二甲酸酯的质量浓度均在0.1~10mg·L-1范围内与其峰面积呈线性关系,方法的测定下限(10S/N)为0.5mg·kg-1(DINP及DIDP)和0.1mg·kg-1(其余21种邻苯二甲酸酯)。以空白样品为基体进行加标回收试验,所得回收率在84.1%~100%之间。     

固相萃取-气相色谱-质谱法测定化妆品中20种邻苯二甲酸酯

提出了同时测定化妆品中20种邻苯二甲酸酯类化合物的固相萃取(SPE)-气相色谱-质谱法(GC-MS)。不含油脂和含油脂的化妆品样品分别以正己烷和乙腈为溶剂作超声固相萃取,使其所含邻苯二甲酸酯类化合物溶于有机相中。萃取液经Cleanert PAE30006-C柱净化,所得净化后溶液进行气相色谱-质谱(GC-MS)分析。质谱分析中采用电子轰击正离子模式(EI+)和选择离子监测(SIM)模式,用外标法定量。20种邻苯二甲酸脂类化合物的质量浓度在0.1~10mg·L~(-1)范围内与峰面积呈线性关系,检出限(3S/N)在0.13~1.04 mg·kg~(-1)之间,样品加标回收率在79.2%~123%之间,相对标准偏差(n=6)在1.7%~12%之间。     

气相色谱-质谱法测定洗涤用品中6种邻苯二甲酸酯

建立了测定洗涤用品中6种邻苯二甲酸酯的气相色谱-质谱法。样品经乙酸乙酯超声提取5min,提取液在HP-5MS毛细管色谱柱上分离,质谱分析中采用电子轰击离子源和选择离子监测模式,外标法定量。6种邻苯二甲酸酯的线性范围为1.0~20mg·L~(-1),方法的检出限(3S/N)均小于1.0mg·kg~(-1);样品中6种邻苯二甲酸酯的加标回收率在85.6%~113%之间,测定值的相对标准偏差(n=6)在2.2%~5.8%之间。     

气相色谱-质谱法测定酒中16种邻苯二甲酸酯

应用气相色谱-质谱法测定酒中16种邻苯二甲酸酯的含量。样品经乙酸乙酯提取,所得提取液用DB-5MS UI色谱柱分离,在全扫描/选择离子监测共用模式下测定。16种邻苯二甲酸酯的质量浓度均在0.5~10.0mg·L-1范围内与其峰面积呈线性关系,方法的检出限(3S/N)在0.01~0.10mg·L-1之间。日间加标回收率在83.7%~114%之间,日间相对标准偏差(n=6)在3.4%~9.8%之间;日内加标回收率在81.9%~113%之间,日内相对标准偏差(n=6)在1.5%~6.7%之间。     

气相色谱-串联质谱法同时测定烟用水基胶中15种邻苯二甲酸酯类化合物

采用气相色谱-串联质谱法同时测定烟用水基胶中15种邻苯二甲酸酯类化合物的含量。烟用水基胶样品0.300g经2mL水分散,用10mL正己烷萃取5min。在气相色谱分离中用DB-35MS色谱柱为固定相,在质谱分析中采用多反应监测模式。15种邻苯二甲酸酯类化合物的质量浓度均在0.05~5.0 mg·L~(-1)内与其对应的峰面积呈线性关系,方法的检出限(3S/N)为0.006~0.027μg·g~(-1)。在4,20,100μg·g~(-1)等3个浓度水平进行加标回收试验,回收率为87.8%~104%,测定值的相对标准偏差(n=6)为1.3%~6.1%。     

超高效液相色谱-串联质谱法测定食品包装材料中18种邻苯二甲酸酯的含量

采用超高效液相色谱-串联质谱法测定食品包装材料中18种邻苯二甲酸酯的含量。食品包装材料样品用正己烷提取,采用Aglient ZDRBAX RRHD Eclipse Plus C~(18)色谱柱(3.0mm×100mm,1.8μm),同时串联ZORBAX Eclipse Plus C~(18)富集柱(2.1mm×50mm,1.8μm),以不同体积比的0.1%(体积分数)甲酸水溶液和甲醇的混合液作为流动相梯度洗脱,采用电喷雾正离子源多反应监测模式检测。18种邻苯二甲酸酯的质量浓度均在0.050~5.0mg·L~(-1)范围内与其峰面积呈线性关系,方法的检出限(3S/N)在0.003~0.030mg·kg~(-1)之间。在0.1,1.0,10.0mg·kg~(-1)等3个浓度水平进行加标回收试验,回收率在87.5%~102%之间,测定值的相对标准偏差(n=6)在0.90%~3.9%之间。     

气相色谱-质谱法测定木塞中10种多氯苯酚的残留量

采用气相色谱-质谱法同时测定木塞中10种多氯苯酚的残留量。样品经甲醇萃取后,在碳酸钾溶液中用乙酸酐乙酰化后再用正己烷萃取,萃取液经DB-5MS毛细管色谱柱分离,质谱分析中选择电子轰击正离子源和选择离子监测模式。10种多氯苯酚的线性范围为1.0~100.0mg·L~(-1),检出限(3S/N)在0.03~0.21mg·kg~(-1)之间.加标回收率在88.4%~104%之间,测定值的相对标准偏差(n=6)在2.1%~4.6%之间。方法用于市售木塞中10种多氯苯酚的测定,检出率为77.8%。     

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%.     

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.     

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.     

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.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

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.