毛细管电泳法测定猪体组织中甜中甜菜碱含量

建立了毛细管电泳法快速测定猪体组织中甜菜碱含量的方法。甜菜碱首先转化为苯甲酰甲基酯后直接上样测定。pH为3.0的磷酸缓冲溶液使甜菜碱酯化物和甜菜碱结构类似物酯化物之间以及酯化物和酯化剂之间都能很好地分离,这也省去了反应混合液的前处理。该法标准曲线的线性范围为4-600mg/L,相关系数r为0.9999,最低检测限为1mg/L,相对标准偏差为2.2%-4.7%,标准加入回收率为95.9%-98.4%。     

抗坏血酸紫外褪色分光光度法测水中余氯

建立了抗坏血酸紫外褪色分光光度法测定水中余氯的新方法. 在pH 2～6介质中, 选择248 nm作为测定波长, 氯质量浓度在0～4.0 mg/L范围服从比尔定律. 回归方程为： ρ=10.109A＋0.0005 （mg/L）, 检出限0.02 mg/L, 水中常见的离子不干扰测定. 该法用于自来水、游泳池水等样品中余氯浓度的测定, 快速简便, 加标回收率在98%～104%之间.     

UPLC-MS/MS法同时检测葡萄和土壤中2种甲氧基丙烯酸酯类杀菌剂残留

采用改进的QuEChERS方法,结合UPLC-MS/MS,建立了葡萄和土壤中同时测定嘧菌酯和吡唑醚菌酯残留快速分析方法。葡萄样品采用乙腈提取,无水MgSO4+乙二胺-N-丙基硅烷+C_(18)固相分散剂净化,土壤样品采用乙腈提取,无水MgSO_4+C_(18)固相分散剂净化,UPLC BEH C_(18)色谱柱分离,三重四极杆电喷雾质谱检测。在质量浓度0. 01～5. 0 mg/L范围内,葡萄和土壤基质中两种杀菌剂的浓度与峰面积之间具有良好的相关性,相关系数均大于0. 99;在葡萄和土壤中添加0. 1～5. 0 mg/kg的嘧菌酯与吡唑醚菌酯,回收率为88. 1%～109. 2%,相对标准偏差为1. 4%～6. 4%。该方法适用于葡萄中和土壤中同时快速检测嘧菌酯和吡唑醚菌酯残留。     

离子色谱法同时测定果汁中20种有机胺、生物胺和阳离子

建立了梯度淋洗-电导抑制-离子色谱法测定果汁中20种有机胺、生物胺和阳离子的方法,通过对流速、色谱柱温度、p H等因素的考察,探索出了适合20种组分测定的多级梯度淋洗条件。结果表明,当流速为0. 25 mL/min,pH在3. 5～4. 5,柱温在40℃时,20种组分在0. 05～2. 00 mg/L浓度范围内具有良好的线性关系(R 0. 99)。20种组分检出限(S/N=3)在0. 0006～0. 0503 mg/L之间;在0. 10,0. 20,1. 00 mg/L 3个添加浓度水平下,回收率为78. 4%～108. 9%,相对标准偏差(RSDs)在2. 1%～7. 3%之间。该方法适用于果汁中20种有机胺、生物胺和阳离子的分析测定。     

气动雾化进样-微波等离子体炬原子发射光谱法测定催化剂中铜和钠

研究了用微波等离子体炬原子发射光谱法(MPT-AES)测定催化剂中铜和钠含量的方法. 考察了测定铜和钠的实验参数, 选择了测定的最佳条件, 并考察了共存离子的干扰情况. 催化剂使用压力溶弹处理, 并用标准加入法来消除基体干扰. 实验结果表明, 铜和钠的检出限分别为2.0、 4.2 μg/L, 方法的RSD均小于2.2%, 线性范围分别为0.01～12.0 mg/L和0.02～8.0 mg/L. 样品测定的RSD均小于2.9%, 加标回收率均在96.1%～102%之间.     

固相萃取-反相高效液相色谱法测定水中的邻苯二甲酸酯

建立了固相萃取-反相高效液相色谱法检测水中3种邻苯二甲酸酯类物质邻苯二甲酸二甲酯、邻苯二甲酸二(2-乙基己基)酯、邻苯二甲酸二正辛酯的方法. 考察了固相萃取柱、洗脱溶剂、洗脱体积、上样速度以及洗脱速度对萃取效率的影响. 通过综合分析, 选定SupelcleanLC-18 SPE Tube固相萃取柱, 甲醇为洗脱剂, 洗脱体积2 mL, 上样速度为4 mL/min, 洗脱速度为1 mL/min. 在此萃取条件下, 萃取回收率在83.4%～121.2%之间. 邻苯二甲酸二甲酯、邻苯二甲酸二(2-乙基己基)酯、邻苯二甲酸二正辛酯质量浓度在2～100 mg/L之间均为线性. 经萃取后, 方法的最低检出限分别为邻苯二甲酸二甲酯0.06 μg/L, 邻苯二甲酸二(2-乙基己基)酯0.16 μg/L, 邻苯二甲酸二正辛酯0.08 μg/L. 方法的精密度在10%～15%之间. 应用该方法测定自来水中酞酸酯类化合物的含量, 加标回收率为83.6%～110.2%.     

气相色谱法分离和测定环境空气中的丙烯酸乙酯和甲基丙烯酸甲酯

用活性炭吸附环境空气中的丙烯酸乙酯和甲基丙烯酸甲酯 ,经二硫化碳 (CS2 )解吸后用气相色谱法测定 .在填充 2 .5 %DNP + 2 .5 %Bentone 34/ChromosorbWHPDMCS的玻璃色谱柱 (长 2m内径 3mm)上 ,丙烯酸乙酯与甲基丙烯酸甲酯及干扰物之间能较好地分离 .方法的回收率 :丙烯酸乙酯为 86.4%～ 1 0 3.0 % ,甲基丙烯酸甲酯为 86.3 %～ 1 0 1 .2 % ,变异系数 :丙烯酸乙酯为 4.1 %～ 4.4% ,甲基丙烯酸甲酯为 4.4%～ 4.9% ,当采样体积为 2 0L ,解吸液体积为 2 .0 0mL ,进样 2 μL时 ,丙烯酸乙酯和甲基丙烯酸甲酯的最低检测浓度分别为 0 .0 2mg/m3和 0 .0 1mg/m3.     

非水溶剂中微量溶解氧的测定

利用分子氧对联吡啶钌的荧光有淬灭作用的特点,建立了一种灵敏的测定非水体系中微量溶解氧的方法.以甲基三甲氧基硅烷(MTMS)和四乙氧基硅烷(TEOS)为共聚前驱体,以联吡啶钌为荧光指示剂制备了新的有机改性溶胶-凝胶氧敏感膜,并将该膜用于有机体系中溶解氧的测定,响应时间小于30 s.对1,3-丁二醇,丙二醇,丙三醇,PEG-400中溶解氧的测定线性范围分别为0～73.6 mg/L,0～116.4 mg/L,0～205.7 mg/L,0～165.0 mg/L;RSD(n=6)分别为3.5%.5.4%,2.8%和1.0%.该法可用于有机溶剂中溶解氧的测定.     

协同催化-溶剂萃取光度法测定血清中的唾液酸

利用Cu2+和Cr3+的协同催化作用,促进间苯二酚与唾液酸的显色,再用乙酸丁酯-正丁醇萃取有色物质,变换波长至625nm处测定血清中的唾液酸含量.建立了血清中唾液酸测定的新方法.方法的线性范围为0～1000mg/L,检出限为2.1 mg/L,相对标准偏差为1.59%～2.11%,回收率为96.2%～101.2%,糖类及抗坏血酸等物质对测定的干扰＜2%.该法简便、快速、灵敏、准确,可用于临床体液中唾液酸的测定.     

萃淋树脂分离-全差示光度法测定环境水样中铬Ⅲ和铬Ⅵ

用CL TBP萃淋树脂分离富集Cr 和Cr 、对氨基二甲基苯胺做显色剂 ,采用全差示光度法测定环境水样中的Cr 和Cr 。方法的表观摩尔吸收系数为 3.42× 10 5L·mol- 1 ·cm- 1 ,线性范围为 0～ 0 .16mg/L ,线性方程为A =6 .7C +0 .0 0 1,(C :mg L) ,r =0 .9996 ,Cr 和Cr 的检测限分别为 8和 6 μg L。测定Cr 和Cr 分别为 18.7和 31.6 μg L ,其相对标准偏差分别为 3.1%(n =6 )和 2 .4%(n =6 )。Cr 和Cr 的标准加入回收率为 93.3%～ 10 2 .3%。用本法测定环境水样中Cr 和Cr ,结果满意。     

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.