毛细管气相色谱法测定中药中有机磷农药残留量

建立了中药中多种有机磷农药残留量的毛细管气相色谱测定方法。样品以丙酮-石油醚混合溶剂为提取剂,超声提取后,用固相吸附层析柱(装填4g弗罗里硅土和2g中性氧化铝)净化,采用GC—FPD法同时测定中药中多种有机磷农药残留量。方法检出限为0．011～0．015μg／mL,回收率为85．5％～107．8％。该法简便、准确,能满足实际样品分析。     

加速溶剂萃取-气相色谱串联质谱法检测沉积物中痕量增塑剂

研究了加速溶剂萃取(ASE)对沉积物中邻苯二甲酸酯类(PAEs)物质的提取效果,建立了快速溶剂萃取/气相色谱-质谱联用(GC/MS)检测沉积物中16种邻苯二甲酸酯类物质的方法。用正己烷和二氯甲烷混合溶剂作为提取溶剂,加速溶剂萃取法萃取沉积物中16种PAEs,再用Florisil层析柱净化,最后用GC/MS对净化后提取液中的PAEs进行定量分析。结果表明:当萃取剂为二氯甲烷-正己烷(1∶1,V/V),萃取温度为80℃时,萃取效率最高,16种PAEs的回收率稳定在81.2%～128.5%之间,相关系数≥0.99,检出限为0.12～0.98 ng/g,相对标准偏差为1.1%～10.8%。加速溶剂萃取法与传统索氏提取法相比,既提高了萃取效率同时又减少了有机萃取溶剂的用量。在检测实际样品时,同时加入3种内标指示剂对方法的性能进行了验证,3种内标的回收率分别为106.0%±18.8%,87.4%±10.8%和81.4%±14.5%,样品中16种PAEs的检出率为100%。前处理方法处理简单,定性与定量分析准确可靠。     

气相色谱/气质联用分析食品及环境基质中特丁硫磷残留量

建立在食品及环境样品中特丁硫磷残留量的气相色谱检测及气质联用确证法。样品采用乙酸乙酯提取、活性炭-酸性氧化铝复合小柱净化,丙酮-正己烷混合溶液（体积比为1：9）洗脱,样液浓缩后经GC—FPD检测．外标法定量,GC—MS定性。GC—FPD法分析时,特丁硫磷在不同样品、不同水平的加标回收率为74．5％～103．3％．RSD为2．1％～11．7％（n=5）,方法的检出限为0．001mg／kg.气质联用法确证时,特丁硫磷的SIM离子为186、231（Q,100）、288.     

复合层析柱净化-气相色谱-负化学源质谱法测定海洋沉积物中多溴联苯醚

采用去活硅胶-酸化硅胶-去活硅胶-弗罗里硅土-无水硫酸钠填装的复合层析柱，结合气相色谱-负化学源质谱法(GC-NCI/MS)对海洋沉积物样品中的13种多溴联苯醚(PBDEs)进行分析检测。样品用正己烷-二氯甲烷(3∶1, v/v)混合溶剂进行超声提取，提取液经复合层析柱净化及正己烷-二氯甲烷(3∶1, v/v)混合溶剂洗脱后，利用GC-NCI/MS的选择离子监测(SIM)模式分析测定13种PBDEs。对比分析了复合层析柱中不同填料、不同洗脱剂以及不同洗脱体积对PBDEs净化效果的影响，并对GC-NCI/MS分析条件进行优化处理。最终13种PBDEs在0.1～20μg/L内线性关系良好，相关系数(r²)>0.995(BED-209,r²>0.99),定量限(S/N=10)为0.002～0.126μg/kg。以海洋沉积物样品为基质，13种PBDEs在0.2、1.0、4.0μg/kg 3个加标水平下的平均回收率分别为85.3%～101.3%、84.8%～113.6%、86.3%～94.7%,相对标准偏差分别为4.4%～14.0%、0.4...     

同位素稀释气相色谱串联质谱法测定海产品中的苯并（α）芘的残留量

采用同位素稀释法结合固相萃取净化,建立了海产品中苯并（α）芘残留的气相色谱串联质谱（6C—MS／MS）检测方法。样品经乙腈一丙酮（体积比6：4）溶液提取,硅胶固相萃取净化,苯并（μ）芘用GC—MS／MS测定,同位素D12-苯并芘内标法定量。方法的平均回收率为93％-98％,相对标准偏差为6.2％～12．2％（n=6）,定量限为0．2μg／kg。用该方法测定FAPAS烟熏鱼有证标准样品,测定值与标准值一致。     

林蛙油中农药残留的GC-MS/MS检测方法

首次建立了林蛙油中15种农药（p,p′DDE,O,p′-DDD,o p′-DDT,p,p′-DDT,BHC（α、β、γ、δ）,异丙威,甲拌磷,六氯苯,百菌清,皮蝇磷,倍硫磷,甲氰菊酯）的GC—MS／MS残留检测方法。样品用乙酸乙酯提取、Florisil层析柱净化后,经GC—MS／MS检测,用外标法定量。15种农药在0．050～10．0mg／L范围内,线性关系良好,相关系数r≥0．996。当添加量在0．050—2．00mg／kg间,平均加标回收率为81％～117％,RSD为2．4％-18．2％,方法的检出限为0．050mg／kg。该方法准确、灵敏,适用于农药残留的分析。     

超声萃取-高效液相色谱法测定沉积物中多环芳烃

提出了高效液相色谱法测定沉积物中多环芳烃(PAH′s)含量的方法。样品中多环芳烃用正己烷-丙酮(1+1)混合溶液超声提取,离心分离后,所得萃取液经蒸发浓缩,然后过装有1g无水硫酸钠和2g硅胶的层析柱净化。以Varian PAHs色谱柱为分离柱,不同比例配成的甲醇和水为流动相梯度洗脱,用荧光检测器检测。方法的检出限(3S/N)在0.34～1.52ng.g-1之间。方法用于沉积物中多环芳烃的测定,测定结果的相对标准偏差(n=5)在3.2%～10.6%之间。用标准加入法测定方法的回收率,结果在57.1%～103.4%之间     

水和生物样品中痕量多氯联苯的分析方法研究

建立了一种水和生物体中痕量多氯联苯的提取、分离以及定性定量分析的新方法。本方法利用超声提取或液液萃取进行提取、硫酸硅胶柱和弗罗里土柱进行净化和分离,毛细管气相色谱进行分析,并优化了硫酸硅胶柱和弗罗里土柱净化分离多氯联苯的条件。水中痕量多氯联苯同类物的平均回收率为82％～115％;检出限为0．009—15．3ng/L,生物样品中痕量多氯联苯同类物的平均回收率75％～135％;检出限为0．02～96．9ng／g;相对标准偏差（RSD）均小于6．9％。方法用于实际水样和生物样品中痕量多氯联苯的分析,取得满意结果。     

超声萃取-气相色谱-质谱联用测定海洋沉积物中39种多溴联苯醚残留

建立了超声萃取-气相色谱-质谱法测定海洋沉积物中39种多溴联苯醚残留的分析方法.样品用V(正己烷):V(二氯甲烷) =1:1混合溶液提取,超声(控制水浴温度为25 ℃)提取60 min,采用硅胶和氧化铝净化,负化学离子源-气相色谱-质谱法进行检测,39种组分图谱在49 min 内能得到很好的分离. 39种混合样品的检出限为0.003～0.10 μg/kg; 加标回收率为66.2%～118.6%;相对标准偏差为0.8%～18.2%.用于实际样品分析,结果令人满意.     

多功能柱净化-高效液相色谱法检测谷物中的玉米赤霉烯酮

建立了玉米和小麦中玉米赤霉烯酮（ZEN）的多功能柱净化-高效液相色谱检测方法。样品经乙腈-水混合溶剂（V（乙腈）：V（水）=84：16）提取,通过多功能净化柱（MFC）进行一次性净化,以Symmetry^R C18柱为分离柱,甲醇-水（V（甲醇）：V（水）=68：32）为流动相进行高效液相色谱分离和检测。玉米赤霉烯酮的质量浓度在0．01～4．0μg／mL范围内呈良好线性,相关系数为0．9996。检出限为0．04μg／g,在0、04—5．0mg／kg添加范围内的回收率为87．5％～98．6％,相对标准偏差为1．5％～8．3％。     

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.