柱前衍生高效液相色谱法同时测定水性涂料中6种醛类化合物

建立了柱前衍生高效液相色谱同时测定水性涂料中甲醛、乙醛、丙醛、苯甲醛、正戊醛和对甲基苯甲醛等6种醛类化合物的方法。样品经水超声提取后,与2,4-二硝基苯肼乙腈溶液在酸性条件下衍生,再经0.45 μm针式过滤器过滤后进样分析。系统考察了酸度调节剂、pH值、反应温度、时间等因素对衍生反应的影响,优化的反应条件为：以稀释后的盐酸溶液作为酸度调节剂,缓冲溶液pH=3,反应温度为60 ℃,反应时间为30 min。在此条件下,于0.08~2.0 mg/L浓度范围内,6种醛类化合物呈良好的线性关系;检出限为0.05~2.50 mg/kg;在2.0、4.0、6.0 mg/kg 3个水平下的加标回收率为87.0%~112.8%;RSD为1.12%~9.54%。结果表明,本方法具有较宽的线性范围,良好的精密度和准确度,适用于水性涂料中6种醛类化合物的同时测定。     

气相色谱-质谱法测定白酒中邻苯二甲酸酯

建立了白酒中15种邻苯二甲酸酯类化合物(PAEs)残留量的气相色谱-电子轰击离子源质谱(GC-EI/MS)测定方法。样品通过旋转蒸发除乙醇,正己烷超声提取,LC-Si SPE小柱净化,氮吹浓缩后进行气相色谱-质谱法分析。结果表明:该方法具有良好的线性关系,相关系数(r2)大于0.998,平均加标回收率为85.3%~103.1%,相对标准偏差为3.8%~8.8%,15种邻苯二甲酸酯(PAEs)的方法检出限(MDL)为0.011~0.041mg/L。该方法具有简单、快速、灵敏度高和定性定量准确等优点,满足各类白酒样品的分析要求。     

在线式红外分光测油仪的校准

建立在线式红外分光测油仪的校准方法。在线式红外分光测油仪的校准主要包括绝缘电阻、示值误差、重复性、漂移和最小检出浓度等项目。通过分析实验数据,测量范围不大于10 mg/L时,示值误差不超过±0.8 mg/L;测量范围大于10 mg/L时,示值相对误差不超过±8%;重复性不大于2%;零点漂移不超过±0.5 mg/L,示值漂移不超过±5%;最小检出浓度不大于0.5 mg/L,仪器的计量性能正常。据此对影响仪器性能的各个参数进行全面评价,确认各项指标控制在合理范围内。该校准方法切实可行,可用于在线式红外分光测油仪的校准。     

GC-MS法测定白酒中邻苯二甲酸酯残留量

采用正己烷提取白酒中的16种邻苯二甲酸酯类增塑剂,建立了气相色谱-质谱联用法测定白酒中污染物邻苯二甲酸酯类增塑剂残留量的检测方法。该方法对白酒中16种邻苯二甲酸酯化合物的检测限为0.05 mg/kg,方法的检测浓度线性范围为0.5~5.0 mg/L,样品的加标回收率为80.0%~95.0%,测定结果的相对标准偏差为2.1%~7.0%(n=6)。该方法可以满足白酒中污染物邻苯二甲酸酯检测的需要。     

气相色谱–质谱法测定白酒中的邻苯二甲酸酯类

采用气相色谱–质谱法对常见名贵白酒中的16种邻苯二甲酸酯类含量进行测定。将样品提取、净化后,经气相色谱–质谱联用仪进行分离测定。采用特征选择离子检测扫描(SIM),以色谱保留时间和色谱碎片的丰度比定性,以峰面积外标法定量。16种邻苯二甲酸酯类物质的含量与色谱峰面积在0~2.0μg/m L范围内线性良好,线性相关系数均在0.995以上,方法检出限为0.05 mg/L。16种邻苯二甲酸酯含量测定结果的相对标准偏差均小于10%(n=6),加标回收率为91.21%~105.22%。该方法样品前处理简单,灵敏度高,适用于同时定性及定量检测白酒中16种邻苯二甲酸酯。     

离子色谱-串联质谱法检测酒类产品中10种有机酸

建立了一种离子色谱-串联质谱(IC-MS/MS)测定白酒、黄酒、干红葡萄酒3种酒类样品中10种有机酸含量的方法。白酒样品氮吹后,经去离子水稀释,用IC-MS/MS分析检测;干红葡萄酒样品和黄酒样品,对比不同固相萃取小柱净化能力,最终选择石墨化炭黑固相萃取小柱进行净化,经去离子水稀释,用IC-MS/MS分析检测。选用高容量、强亲水性的Dionex IonPac^TM AS11-HC型阴离子分析柱进行分离,以淋洗液自动发生器在线产生的KOH水溶液为淋洗液,进行梯度淋洗。淋洗液经抑制器抑制后直接进入电喷雾电离串联质谱(ESI-MS/MS),采用负离子模式电离,多反应监测(MRM)模式检测,外标法定量。在该实验条件下:草酸、富马酸、马来酸、苹果酸、酒石酸、柠檬酸、奎尼酸和乌头酸在0.05~2 mg/L范围内线性关系良好;琥珀酸在0.05~5 mg/L范围内线性关系良好;乳酸在0.05~10 mg/L范围内线性关系良好(相关系数r²>0.99)。10种有机酸的检出限(S/N=3)在1.0~8.0 μg/L范围内,定量限(S/N=10)在3.5~26.5 μg/L范围内,在3个不同浓度的添加水平下,平均回收率在83.0%~112.1%之间,相对标准偏差≤9.1%,满足检测要求。该方法前处理简单,不使用有机溶剂,不需进行衍生化处理,测定快速、准确,灵敏度高,适用于3种酒类样品中10种有机酸的定量分析,为酒类食品的风味及品质测定提供方法支持。     

全自动红外测油仪的研制

研制新型全自动红外测油仪。通过对进样系统、萃取系统、吸附过滤系统和检测系统自动化和集成化设计,实现了对水中油分的全自动检测。仪器的测量范围为0～200 mg/L。自动进样器取样体积误差在1%以内,仪器示值误差在样品浓度不大于10 mg/L时为0.1 mg/L,样品浓度大于10 mg/L时为0.9%,仪器重复性为0.2%(n=6),零点漂移为–0.1 mg/L,示值漂移为0.6%,最小检出浓度为0.1 mg/L,两种水样测量结果的相对标准偏差分别为1.28%和0.91%(n=11),加标回收率分别为96.8%和96.1%,检出限为0.006 mg/L。该仪器测量准确,性能稳定,能够降低工作强度,提高工作效率,减少有机物危害,为环境监测提供有效保障。     

酒精度对高效液相色谱-荧光法分析白酒中氨基甲酸乙酯含量的影响

分析酒精度对高效液相色谱-荧光（HPLC-FLD）法测定白酒中氨基甲酸乙酯（EC）含量的影响,建立了快速检测白酒中EC含量的HPLC-FLD分析方法。通过比较不同酒精度下同一EC含量的峰面积,研究酒精度对EC含量测定的影响。结果表明,在5%~65%（v/v）酒精度范围内,酒精度与EC含量（峰面积）具有良好的线性关系,相关系数R²大于0.98,同时建立了不同酒精度间EC含量换算的相对校正系数。该方法在10~500 μg/L范围内呈良好的线性关系,R²大于0.9999,定量限为10 μg/L,加标回收率为98.9%~108.2%,相对标准偏差为0.6%~4.9%。评价了HPLC-FLD法的可靠性,将该方法与GC-MS方法比较,结果显示两种方法无明显差异。该方法简单、灵敏、准确,适用于白酒中EC含量的快速测定,具有较好的实际应用价值。     

气相色谱-质谱法同时测定蔗汁中的莠去津与莠灭净残留量

建立了气相色谱-质谱法(GC-MS/SIM)同时测定蔗汁样品中莠去津和莠灭净的方法,并优化了样品前处理和色谱条件.在优化条件下,两种除草剂在0.00-0.60 mg/L范围内线性关系良好,方法的检出限(S/N=3)均为0.001 mg/L.在加标水平为0.050-0.100 mg/L时,两种除草剂的回收率在93%-10...     

GC–MS法测定白酒中邻苯二甲酸二丁酯和邻苯二甲酸二(2-乙基)己酯

采用正己烷提取白酒中的邻苯二甲酸二丁酯(DBP)、邻苯二甲酸二(2-乙基)己酯(DEHP),建立了气相色谱–质谱法测定白酒中DBP,DEHP残留量的检测方法。对氮吹、水浴、盐析和直接提取4种方法的提取效率进行考察,选择氮吹法处理样品。在0.20~20 mg/L范围内DBP,DEHP的质量浓度分别与色谱峰面积呈良好的线性关系,线性相关系数分别为0.999 3,0.999 8。方法的定量限(S/N=10)为0.04 mg/kg,加标回收率在82.0%~92.5%之间,测定结果的相对标准偏差为1.91%~4.83%(n=6)。该方法适合白酒中DBP,DEHP残留量的日常检测。     

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.     

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.     

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.     

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.