固相萃取富集-高效液相色谱法测定环境水中多菌灵和噻菌灵

建立了以固相萃取技术富集，高效液相色谱法进行分离和检测多菌灵和噻菌灵2种杀菌剂的方法。环境水中的多菌灵和噻菌灵用3M Empore 6mL C18 Cartridge进行固相萃取。以Hypersil ODS柱为分析柱，优化得到高效液相色谱分离条件：流动相为甲醇-水(50：50，V/V)；流速为0．7mL／min；柱温为55℃；在286nm波长下检测，检出限为0．05mg／L。本法操作简便，灵敏，回收率高。     

固相萃取富集高效液相色谱法测定苯氧乙酸和2，4—二氢苯氧乙酸

建立了以固相萃取技术进行富集,高效液相色谱法进行分离和检测苯氧乙酸和2,4－二氯苯氧乙酸的方法。环境水中的苯氧乙酸和2,4－二氯苯氧乙酸用Sep-Pak C18 Cartridge进行固相萃取。液相色谱的条件是：Shim-Pack CLC ODS柱为分析柱;甲醇－水（9：1,V／V）为流动相;流速为1mL/min;在UV－275nm波长下进行检测。本法具有良好的灵敏度和重现性。     

固相萃取富集高效液相色谱法测定苯氧乙酸和2,4-二氯苯氧乙酸

建立了以固相萃取技术进行富集 ,高效液相色谱法进行分离和检测苯氧乙酸和 2 ,4 二氯苯氧乙酸的方法。环境水中的苯氧乙酸和 2 ,4 二氯苯氧乙酸用Sep PakC18Cartridge进行固相萃取。液相色谱的条件是 :Shim PackCLCODS柱为分析柱 ;甲醇 水 (9∶1,V/V)为流动相 ;流速为 1mL/min ;在UV 2 75nm波长下进行检测。本法具有良好的灵敏度和重现性     

在线固相萃取/高效液相色谱法测定环境水样中的4种痕量邻苯二甲酸酯

建立了一种在线固相萃取/高效液相色谱测定水样中4种痕量邻苯二甲酸酯(邻苯二甲酸甲酯、邻苯二甲酸乙酯、邻苯二甲酸丁酯和邻苯二甲酸(2-乙基)己酯)的新方法.样品由外加泵注入一根固相萃取小柱上进行富集,再将富集柱切换至高效液相色谱系统中,将富集在固相萃取小柱的邻苯二甲酸酯洗脱至分析柱进行分析.在线固相萃取柱为IonPac(...     

环境水中甲基对硫磷、对硫磷和辛硫磷农药残留的SPE-HPLC分析

采用离线固相萃取 (SPE)富集 -高效液相色谱(HPLC)分离和紫外分光光度法检测 ,对环境水中甲基对硫磷、对硫磷和辛硫磷3种有机磷农药进行分析;固相萃取用C18 萃取柱 ,用甲醇洗脱 ,高效液相色谱分离以Shim_PackCLCODS柱(150mm×4.6mmid,5μm)为分离柱 ,流动相为甲醇 -水(体积比70∶30) ,紫外检测波长为280nm;该法稳定可靠 ,回收率高     

高效液相色谱-质谱法分析测定水中氨基甲酸酯

采用固相萃取-高效液相色谱-质谱法（LC／MS）检测研究了水中氨基甲酸酯农药残留。水样用固相萃取富集净化,环己烷＋乙酸乙酯（1＋1）洗脱;以甲醇-10mmol／L乙酸铵为梯度流动相,Symmetry C18柱高效液相色谱分离。电喷雾正离子模式,选择质子化氨基甲酸酯分子离子[M＋H]^＋为定量离子进行MS测定。结果表明,6种氨基甲酸酯组分的平均加标回收率为73．5％～89．8％;相对标准偏差为4．50％～12．6％;水样浓缩至1／2500后的检出限为0．8～3．2ng／L。本法具有非常高的选择性、灵敏度和准确度,完全能满足水中痕量氨基甲酸酯农残的高灵敏分析。     

固相萃取富集-高效液相色谱分离和测定邻甲苯胺和邻硝基甲苯

建立了以固相萃取技术进行富集 ,高效液相色谱进行分离和检测邻甲苯胺和邻硝基甲苯的方法。污染水中的邻甲苯胺和邻硝基甲苯采用Sep pakC1 8萃取柱进行固相萃取。色谱分离条件是 :Shim PackCLCODS(1 5 0mm× 4 .6mmid ,5 μm)柱为分析柱 ,甲醇 水 =60∶4 0 (V V)为流动相 ,流速为 1 .0mL min,邻甲苯胺和邻硝基甲苯的紫外检测波长分别为 2 3 0nm和 2 5 4nm ,本法具有良好的灵敏度和重现性。     

流动注射在线预富集-高效液相色谱法测定水中的4-壬基酚和双酚A

建立了以香烟过滤嘴作吸附剂,在线固相萃取(SPE)与高效液相色谱(HPLC)联用测定水中双酚A(bisphenol A,BPA)和4-壬基酚(4-nonylphenol,4-NP)的方法。对于高效液相(HPLC)在线固相萃取而言,采用内置香烟过滤嘴的预富集圆形柱来代替传统的高效液相仪中的注射管进样环用于在线固相萃取。通过流动注射仪将样品分析物负载加入到预富集柱中,随后采用V(甲醇):V(H2O)=93:7混合液为洗脱剂对富集的样品分析物进行洗脱。采用Eclipse XDB-C18色谱柱,V(甲醇):V(H2O)=93:7混合液为流动相,流速为1.0mL/min,紫外检测波长为227nm,保留时间定性,外标法定量。双酚A在0.005～0.8mg/L、4-壬基酚在0.04～8.0mg/L范围内,两者峰面积与浓度呈线性关系,相关系数分别为0.9985和0.9983,检出限(S/N=3)分别为2.1和10.0μg/L,富集倍数分别为816和346倍。对标准混合物(BPA:0.2mg/L;4-NP:2.0mg/L)重复测量11次的相对标准偏差为2.3%和1.5%。本方法用于当地河流水样中BPA和4-NP的测定,回收率为93.2%～105.4%。     

在线固相萃取富集高效液相色谱法测定水中有机锡化合物

建立了在线固相萃取富集-反相高效液相色谱测定水样中四苯基锡(TrPhT)、四乙基锡(TrET)、四丁基锡(TrBT)的方法。使用C18柱作为在线固相萃取富集柱,以C8反相柱作为分离柱,V(甲醇)∶V(H2O)=90∶10)(内含0.05%三氟乙酸)作为流动相在线分离有机锡化合物。3种有机锡化合物TrPhT、TrET、TrBT的检出限分别为1.7、7.3、7.3μg/L。3种有机锡化合物的回收率在80.8%~90.1%之间,测定的相对标准偏差在2.9%~9.3%之间。用建立的方法测定水中有机锡化合物得到了满意的结果。     

固相萃取-高效液相色谱法同时测定水中的16种苯脲除草剂(英文)

 建立了固相萃取 高效液相色谱 (SPE HPLC)同时测定水中 16种苯脲除草剂的方法。HPLC采用Lichrospher 10 0RP 18e柱 ,紫外检测波长为 2 40nm ,流动相为乙腈水溶液 ,流速为 1mL/min ,采用梯度洗脱方式。HPLC分析时间少于 2 0min。水中的除草剂用C18柱固相萃取富集 10 0 0倍。在优化的条件下 ,各成分的添加回收率为 87 8%～ 10 3 7%。     

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.