超高效液相色谱法测定香型中性笔墨水中10种PAEs

建立超高效液相色谱–二极管阵列检测器测定香型中性笔墨水中邻苯二甲酸二甲酯(DMP)、邻苯二甲酸二乙酯(DEP)、邻苯二甲酸二正丙酯(DPP)、邻苯二甲酸丁基苄酯(BBP)、邻苯二甲酸二正丁酯(DBP)、邻苯二甲酸二正戊酯(DAP)、邻苯二甲酸二环己酯(DCHP)、邻苯二甲酸二正己酯(DHP)、邻苯二甲酸二(2-乙基己基)酯(DEHP)和邻苯二甲酸二正辛酯(DNOP)10种邻苯二甲酸酯(PAEs)的方法。样品采用甲醇涡旋超声提取,色谱柱为Waters ACQUITY UPLC BEH C_(18)柱(100 mm×2.1 mm,1.7μm),以乙腈–水为流动相进行梯度洗脱,用PDA检测器检测,10 min内完成10种邻苯二甲酸酯的检测。10种邻苯二甲酸酯的质量浓度在5.0~200.0 mg/L范围内与其色谱峰面积呈良好的线性关系,线性相关系数均大于0.999,检出限为3.2~4.0 mg/kg;在高低两个添加水平下,10种邻苯二甲酸酯的回收率为96.3%~104.1%,测定结果相对标准偏差为0.1%~2.9%(n=6)。该方法样品处理简单,提取效率高,分离效果好,且灵敏度高,能快速准确测定香型中性笔墨水中10种邻苯二甲酸酯。     

热解析低温等离子体电离源用于糯高粱中农药残留的快速筛查

本研究设计并搭建了一套热解析低温等离子体电离源(TD-LTP),与质谱联用实现了糯高粱中农药残留的快速和高灵敏检测.TD-LTP由热解析装置和低温等离子体放电源两部分组成,农药残留样品首先在热解析进样器内汽化,再由载气载带进入等离子体区域被电离.热解析进样器使LTP产生的气相等离子体与样品之间的气-固或气-液相互作用转变为气-气相互作用,大大提高了难挥发样品(如农药)的电离效率;电离源与质谱进样口之间采用同轴连接,提高了离子的利用率和传输效率.与传统的LTP电离源相比,TD-LTP电离源的灵敏度提高了8倍以上,稳定性提高了4倍.本研究对热解析低温等离子体电离源的各参数进行了优化,并与自制的矩形离子阱质谱相结合,研究了12种农药在该电离源下的特征离子.最后,将此电离源与商品化的三重四极杆质谱仪联用,对糯高粱样品中的12种农药残留进行了快速筛查,结果表明,本方法灵敏度高,可以满足食品安全国家标准规定的谷物中农药残留最大限量检测要求.     

固相萃取/高效液相色谱-串联质谱法测定罗非鱼中9种邻苯二甲酸酯

建立了罗非鱼中邻苯二甲酸二（2-甲氧基）乙酯（DMEP）、邻苯二甲酸二乙酯（DEP）、邻苯二甲酸丁基苄基酯（BBP）、邻苯二甲酸二（2-丁氧基）乙酯（DBEP）、邻苯二甲酸二戊酯（DPP）、邻苯二甲酸二（4-甲基-2-戊基）酯（BMPP）、邻苯二甲酸二己酯（DHXP）、邻苯二甲酸二（2-乙基）己酯（DEHP）、邻苯二甲酸二正辛酯（DNOP）共9种邻苯二甲酸酯（PAEs）的高效液相色谱-串联质谱测定方法。样品经乙酸乙酯提取后,经LC-Si固相萃取柱净化,以甲醇和甲酸-乙酸铵缓冲溶液为流动相,梯度洗脱,采用HPLC-MS/MS电喷雾正离子（ESI+）电离,多反应监测（MRM）模式检测,基质匹配外标法定量。9种PAEs在1.0~200.0 μg?L-1范围内均具有良好的线性关系,相关系数不低于0.991 8,平均加标回收率为75%~107%,批内、批间相对标准偏差分别在1.9%~11.8%和3.6%~13.1%之间。该方法具有简单、快速、灵敏度高和定性准确等优点,满足残留分析的要求。     

加速溶剂萃取-液相色谱-串联质谱法测定玩具中6种邻苯二甲酸酯增塑剂

建立了加速溶剂萃取-液相色谱-串联质谱法测定玩具中邻苯二甲酸二丁酯(DBP)、邻苯二甲酸丁苄酯(BBP)、邻苯二甲酸二(2-乙基)己酯(DEHP)、邻苯二甲酸二正辛酯(DNOP)、邻苯二甲酸二异壬酯(DINP)和邻苯二甲酸二异癸酯(DIDP)6种邻苯二甲酸酯类增塑剂的分析方法。采用加速溶剂萃取方式提取样品中6种增塑剂,二氯甲烷作溶剂,外标法定量,LC-MS/MS分析时间12 min。玩具中DBP、BBP、DEHP、DNOP、DINP和DIDP平均加标回收率92.7%～101.4%;平均相对标准偏差为3.3%～4.1%;检出限分别为50、10、40、40、90和100μg/kg。方法已经应用于玩具材料中上述6种增塑剂的测定。     

气相色谱-质谱法测定玩具中邻苯二甲酸酯类增塑剂

采用二氯甲烷作为萃取溶剂,超声提取塑料玩具和毛绒玩具中的6种增塑剂,提出了邻苯二甲酸二正丁酯(DBP)、邻苯二甲酸(2-乙基己基)酯(DEHP)、邻苯二甲酸二异壬酯(DINP)、邻苯二甲酸丁苄酯(BBP)、邻苯二甲酸二正辛酯(DNOP)和邻苯二甲酸二异癸酯(DIDP)等6种增塑剂的气相色谱-质谱分析方法。在选定的试验条件下,BBP、DBP、DEHP和DNOP可以完全分离,通过比较保留时间、色谱图和峰面积(m/z 149),可实现以上4种物质的定性和定量分析。而DIDP和DINP的峰重叠,需通过选择m/z293,307质谱峰进行定量分析。结果表明方法能够有效地检测出玩具中邻苯二甲酸酯类增塑剂的含量。     

气相色谱法测定邻苯二甲酸酯

建立了气相色谱分析邻苯二甲酸酯的方法.选择邻苯二甲酸二甲酯(DMP)、邻苯二甲酸二乙酯(DEP)、邻苯二甲酸二异丁酯(DIBP)、邻苯二甲酸二正丁酯(DBP)、邻苯二甲酸丁苄酯(BBP)、邻苯二甲酸二(2-乙基己基)酯(DEHP)、邻苯二甲酸二正辛酯(DOP)7种标物,对实验方法的准确程度进行了分析.7种标物的线性相关系数都能达到0.999以上,线性范围在0.01～1g/L之间;保留时间的相对标准偏差都在0.1%以内,峰面积的相对标准偏差在2%以内.     

基质固相分散-气相色谱/质谱法测定蔬菜中的邻苯二甲酸酯

利用基质固相分散-气相色谱/质谱法测定了蔬菜中的邻苯二甲酸二甲酯、邻苯二甲酸二乙酯、邻苯二甲酸二丁酯、邻苯二甲酸丁基苄基酯和邻苯二甲酸二异辛酯。蔬菜样品经弗罗里硅土和石墨化炭黑研磨均匀后,用乙酸乙酯淋洗净化,结果表明:上述5种邻苯二甲酸酯在0.05~10.00 mg/L 范围内具有良好的线性,样品的添加回收率为76%~90%,相对标准偏差为2%~7%,5种邻苯二甲酸酯的检出限为0.01~0.024 mg/kg。该方法操作简便、经济,分析速度快,适用于大批量样品的分析。     

淮安市不同水体中邻苯二甲酸酯的固相萃取-超高效液相色谱-串联质谱法测定及其污染特征研究

建立一种固相萃取(SPE)富集,超高效液相色谱-串联质谱法(UHPLC-MS/MS)检测水中6种痕量邻苯二甲酸酯类化合物[PAEs,包括邻苯二甲酸二(4-甲基-2-戊基)酯(BMPP)、邻苯二甲酸二己酯(DHXP)、邻苯二甲酸二环己酯(DCHP)、邻苯二甲酸二(2-丁氧基)乙酯(DBEP)、邻苯二甲酸二(2-乙基)己酯...     

气相色谱-质谱法快速测定南疆特色林果土壤中22种邻苯二甲酸酯类残留

建立了气相色谱-质谱法(GC-MS)测定南疆特色林果土壤中22种邻苯二甲酸酯类化合物残留的分析方法。样品经超声提取,离心分离,Al2O3小柱净化,进气相色谱-质谱检测。在该条件下,采用内标法定量,EI模式下,22种邻苯二甲酸酯在0.05~5mg/L范围内呈现良好的线性,检测限为0.4~10μg/kg,回收率为78.5%~108.2%。经过对南疆三个林果区的90个土壤样品分析,得出最主要的邻苯二甲酸酯类污染物为邻苯二甲酸二异丁酯,邻苯二甲酸二丁酯和邻苯二甲酸(2-乙基己)酯,部分达到了严重污染。所建立的方法准确度高,灵敏度好,适合土壤样品中邻苯二甲酸酯类物质的测定。     

固相萃取/高效液相色谱-串联质谱法测定罗非鱼中9种邻苯二甲酸酯

建立了罗非鱼中邻苯二甲酸二(2-甲氧基)乙酯(DMEP)、邻苯二甲酸二乙酯(DEP)、邻苯二甲酸丁基苄基酯(BBP)、邻苯二甲酸二(2-丁氧基)乙酯(DBEP)、邻苯二甲酸二戊酯(DPP)、邻苯二甲酸二(4-甲基-2-戊基)酯(BMPP)、邻苯二甲酸二己酯(DHXP)、邻苯二甲酸二(2-乙基)己酯(DEHP)、邻苯二甲酸二正辛酯(DNOP)共9种邻苯二甲酸酯(PAEs)的高效液相色谱-串联质谱测定方法。样品经乙酸乙酯提取后,经LC-Si固相萃取柱净化,以甲醇和甲酸-乙酸铵缓冲溶液为流动相,梯度洗脱,采用HPLC-MS/MS电喷雾正离子(ESI+)电离,多反应监测(MRM)模式检测,基质匹配外标法定量。9种PAEs在1.0～200.0μg.L-1范围内均具有良好的线性关系,相关系数不低于0.991 8,平均加标回收率为75%～107%,批内、批间相对标准偏差分别在1.9%～11.8%和3.6%～13.1%之间。该方法具有简单、快速、灵敏度高和定性准确等优点,满足残留分析的要求。     

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%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

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.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

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.