超声提取-气相色谱法测定纺织品中三氯生

建立了一种气相色谱-电子捕获检测(GC-ECD)法测定纺织品中的三氯生,以二氯甲烷为提取溶剂,超声提取纺织品中的三氯生,并对提取条件进行了优化.该方法简便快速、灵敏度高,检出限(S/N=3)为5μg/L,平均回收率为99.11％～100.71％,相对标准偏差(RSD)为3.92％～6.85％.采用该方法对实际样品进行了...     

稳定同位素稀释液质串联法测定抗菌纺织品中3种含氯防霉抗菌

建立了抗菌纺织品中三氯生、三氯卡班以及五氯酚等3种含氯抗菌剂的同位素稀释-液相色谱串联质谱的分析方法。样品用甲醇超声提取,聚酰胺粉净化。以水/乙腈为流动相,采用梯度洗脱,在Waters Acquity UPLC BEH C18色谱柱(2.1 mm×100 mm,1.7μm)上进行分离,以多反应监测负离子模式进行检测,内标法定量。三氯生和五氯酚在0.5~100.0μg/L,三氯卡班在0.1~50.0μg/L范围内具有良好的线性,样品的回收率为80.0%~110.0%,相对标准偏差(RSD)为1.6%~5.4%,方法的定量限为0.1~0.5μg/kg,检出限为0.03~0.16μg/kg。方法前处理简单,试剂可用于纺织品中三氯生、三氯卡班和五氯酚的含量检测。     

高效液相色谱法测定抗菌乳膏中的三氯生

建立高效液相色谱测定抗菌乳膏中三氯生的分析方法。以甲醇–水(90∶10)为萃取剂对样品中的待测物进行超声提取,上清液离心过滤后,经Hypersil ODS2 C18色谱柱分离,以甲醇–水(80∶20)为流动相,用紫外检测器测定,外标法定量。三氯生的质量浓度在10~110 mg/L范围内与色谱峰呈良好的线性关系,线性相关系数(r2)为0.999 6,在3个不同加标水平下,加标回收率为93.0%~100.3%,测定结果的相对标准偏差在1.2%~9.1%(n=6)之间。该方法满足抗菌乳膏中三氯生快速检测的要求。     

亲水作用液相色谱-串联质谱测定水产品中的消毒剂残留

首次建立了水产品中消毒剂二氯异氰尿酸和三氯异氰尿酸总残留量以及三氯生残留量的液相色谱-串联质谱(LC-MS/MS)同时测定方法。水产样品用乙腈-5%氨水(体积比30∶70)提取,HyperSep RetainAX SPE固相萃取小柱净化,采用亲水作用色谱柱SeQuant ZIC-HILIC分离,以(0.1%甲酸+10 mmol/L乙酸铵)水溶液-乙腈体系为流动相进行梯度洗脱,在电喷雾负离子模式下以多反应监测(MRM)方式检测。结果表明,在0.042～2.4 mg/L质量浓度范围内线性良好,相关系数大于0.99,在3个不同加标水平下,平均回收率为68%～96%,相对标准偏差(RSD)为5.9%～10.9%,检出限(LOD,S/N=3)和定量下限(LOQ,S/N=10)分别为0.015、0.05 mg/kg。实际样品测定表明,该方法适用于各种水产品中三氯生、二氯异氰尿酸和三氯异氰尿酸消毒剂残留量的测定。     

牙膏中三氯生的高效液相色谱法检测

利用甲醇超声提取牙膏样品中的三氯生,采用高效液相色谱法(紫外检测器)测定了其含量;探讨了最佳提取和色谱检测条件.结果表明,该方法对牙膏中三氯生的检出限为1.0μg/g,在三氯生浓度10.5～210mg/L范围内线性关系良好,相关系数R=0.999 98;样品加标回收率为99.81%～103.33%,相对标准偏差为0.03%.该方法具有简便、快速、准确、灵敏的优点,适用于牙膏中三氯生的测定.     

微波辅助萃取/气相色谱法测定抗菌纺织品中的三氯生

以二氯甲烷为萃取溶剂,采用微波辅助萃取技术萃取抗菌纺织品中的三氯生,建立了一种气相色谱-电子捕获检测器(GC-ECD)方法对纺织品中的三氯生进行了测定。 对于阳性样品,采用GC/MS技术进行确认。 该方法简单快速、灵敏度高,检出限为1 μg/kg(S/N=3),回收率为90%~106%,RSD均小于6%。 采用该方法对市售的抗菌纺织品进行测定,结果显示,部分市售抗菌纺织品中含有高浓度的三氯生。     

高效液相色谱法同时测定纺织品中四氯苯酚同分异构体及五氯苯酚和邻苯基苯酚

建立了高效液相色谱法同时测定纺织品中四氯苯酚同分异构体(2,3,4,5-TeCP、2,3,4,6-TeCP、2,3,5,6-TeCP)及五氯苯酚(PCP)和邻苯基苯酚(OPP)的分析方法。样品经甲醇超声提取、浓缩后,采用Symmetry C18色谱柱,以甲醇-10mmol/L乙酸铵溶液为流动相,梯度洗脱,二极管阵列检测器210nm检测。结果表明:三种TeCP同分异构体及PCP、OPP在0.1~20mg/L范围内具有良好的线性关系,相关系数为0.9994~0.9998,样品加标回收率为87.2%~109%,相对标准偏差为0.92%~4.50%,方法的最低检测浓度分别为0.05、0.10、0.05、0.05、0.05mg/kg。该方法高效、简便、准确可靠,可实现现行法规所要求的纺织品中苯酚类物质的同时测定。     

固相萃取/超高效液相色谱法测定纺织品中14种紫外吸收剂

建立了固相萃取(SPE)净化,超高效液相色谱(UPLC)同时测定纺织品中14种二苯甲酮类(BPs)和苯并三唑类(BZTs)紫外吸收剂的分析方法。样品以甲醇-四氢呋喃超声提取,提取液经ENVI-Carb固相萃取柱净化后,在C18色谱柱和乙腈-0.1%甲酸水流动相下梯度洗脱分离,二极管阵列检测器测定。结果表明,14种紫外吸收剂在0.1~50 mg/L浓度范围内线性关系良好,相关系数均大于0.999;方法检出限为1~5mg/kg;阴性涤纶和腈纶样品在3个加标水平下的平均回收率(n=6)为81.5%~99.1%,相对标准偏差(RSD)为2.8%~7.5%。该方法简单快速,回收率和精密度良好,适用于纺织品中14种紫外吸收剂的同时测定。     

高效液相色谱法测定纺织品中1-甲基-2-吡咯烷酮的含量

建立了纺织品中1-甲基-2-吡咯烷酮(N-Methylpyrrolidone,NMP)的高效液相色谱检测方法。样品经超声提取,采用ZORBAX SB-C18色谱柱分离,流动相为乙腈-水(30/70,V/V),检测波长210nm。结果表明,在0.4~48mg/L范围内,NMP的响应峰面积与其质量浓度呈良好的线性关系,相关系数r=0.9997,检测限(S/N=3)为0.2mg/kg,定量限(S/N=10)为0.4mg/kg,平均回收率为80.6%~108.6%。方法具有较高的灵敏度,可简便、快速地测定纺织品中NMP的含量。     

LTQ-Orbitrap组合式高分辨质谱测定纺织品中的15种邻苯二甲酸酯

建立了线性离子阱-静电场轨道肼高分辨质谱(LTQ-Orbitrap)快速同时测定纺织品中15种邻苯二甲酸酯残留的方法,并根据精确地分子离子峰和子离子峰进行定性和确证.样品经甲醇提取,用Agilent Eclipse XDB-C18色谱柱(3.5×100mm,3.5μm),以甲醇-5mmol/L乙酸铵(含0.1%甲酸,V/V)溶液为流动相,FT正离子扫描模式进行质谱检测,外标法定量.结果表明,该方法在0.05~5.0 mg/L范围内线性关系良好(r≥0.99),检出限为2.0mg/kg.按照建立的方法进行了2.0、5.0和10.0mg/kg 3个添加水平的15种邻苯二甲酸酯的加标回收试验,回收率为81.3%~103.2%,相对标准偏差为5.7%~12.9%.本文利用LTQ-Orbitrap高分辨质谱配合全自动筛选应用软件ToxID可以对大量数据文件进行高通量分析的特点,建立了纺织品中15种邻苯二甲酸酯残留的快速筛选和确证方法.     

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%.     

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.     

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.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

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.