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-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%。     

同位素稀释内标-气相色谱-质谱法测定植物油中16种邻苯二甲酸酯的含量

植物油样品0.400 0g,加混合内标溶液20μL混匀,经乙腈4mL超声提取15min。离心后,提取液经活化的SILICA/PSA混合玻璃固相萃取柱净化。净化液经氮气吹干后,残渣用正己烷溶解并稀释至1.0mL。待测液采用DB-5MS UI色谱柱进行气相色谱分离,采用电子轰击离子源和选择离子监测模式进行质谱分析,同位素内标法定量。16种邻苯二甲酸酯类化合物的线性范围均在0.01~1.00mg·L~(-1)之间,检出限(3S/N)在0.003 0~0.035mg·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81.7%~113%之间,测定值的相对标准偏差(n=6)在2.8%~11%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-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。     

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。     

超声萃取分离-气相色谱-质谱法测定土壤中的3种酰胺类化合物含量

采用超声萃取-气相色谱-质谱法测定土壤中N,N-二甲基甲酰胺、N,N-二甲基乙酰胺和N,N-二甲基丙烯酰胺等3种酰胺类化合物的含量。样品经丙酮超声提取,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和选择离子监测模式。3种酰胺类化合物的质量浓度均在0.05~20.0mg·L~(-1)范围内与其峰面积呈线性关系,方法的检出限(3S/N)在0.5~1.5mg·kg~(-1)之间。加标回收率在85.3%~110%之间,测定值的相对标准偏差(n=7)在1.5%~5.3%之间。     

气相色谱-质谱法测定汽油中8种醚类和苯胺类添加剂

采用气相色谱-质谱法同时测定汽油8种醚类和苯胺类化合物。采用强极性离子液体色谱柱(SLB-1L 111毛细管色谱柱)分离样品,质谱中选择电喷雾离子源-选择离子监测模式,以苯乙酮为内标物进行定量分析。8种化合物的质量分数在10~10 000 mg·kg-1范围内与其峰面积呈线性关系,检出限(3S/N)在0.2~2.0 mg·kg-1之间。加标回收率在91.2%~111%之间,测定值的相对标准偏差(n=7)在0.18%~3.0%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%.     

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.     

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.     

Knoevenagel condensation catalyzed by novel Nmm-based ionic liquids in water

A series of novel N-methyl morpholine (Nmm) based ionic liquids with 1,2-propanediol group were synthesized and used as catalysts for Knoevenagel condensation at room temperature in water. Under the effect of the catalyst, various aldehydes or aliphatic ketones could react with a wide range of activated methylene compounds well, including malononitrile, alkyl cyanoacetate, cyanoacetamide, β-diketone, barbituric acid, 2-arylacetonitrile and thiazolidinedione. Furthermore, most of the products could be separated just by filtrating and washing with water. Additionally, the catalyst is recyclable and applicable for the large-scale synthesis.     

Construction of polyheterocyclic spirotetrahydrothiophene derivatives via sulfa-Michael/aldol cascade reaction

A series of polyheterocyclic spirotetrahydrothiophene derivatives were obtained in moderate to excellent yields via a catalyst-free sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 under mild conditions. We also present the first asymmetric sulfa-Michael/aldol cascade reaction of chalcones 1 and commercially available 1,4-dithiane-2,5-diol 2 with moderate to good enantioselectivities catalyzed by readily available chiral phase-transfer catalysts (PTCs).     

Suzuki-Miyaura reactions of the soluble guanylate cyclase inhibitor NS2028: a non-product specific route to C-8 substituted analogues

Both soluble guanylate cyclase (sGC) inhibitors ODQ 1 and NS2028 2 are synthesized via improved protocols. In the former case treating 3,4-dihydroquinoxalin-2(1H)-one oxime 8, which can be prepared in two steps from 1,2-benzenediamine, with 1,1′-carbonyldiimidazole (CDI) gives the dihydro-ODQ 10 that in the presence of KMnO₄ oxidises to give ODQ 1 in an overall yield of 46% starting from 1,2-benzenediamine. In the latter case, the synthesis affords NS2028 2 from 2-amino-4-bromophenol 3 in three steps with an overall yield of 85% and avoids the need for chromatography. Furthermore, Suzuki-Miyaura reaction conditions are described that enable the preparation of 8-aryl and 8-heteroaryl derivatives of NS2028 directly from NS2028 2. Finally, demethylation of the 8-(methoxyphenyl) substituted analogues afforded the 8-(hydroxyphenyl) derivatives 40-42. All new products are fully characterised.