超高效液相色谱-串联质谱法测定水产品中三聚氰胺残留量

建立超高效液相色谱-串联质谱(UPLC-MS/MS)快速测定水产品中三聚氰胺残留的方法.采用ACQUITY UPLC BEH HILIC色谱柱(100 mm×2.1 mm, 1.7 μm),流动相为乙腈-0.5 mmol/L乙酸铵溶液(0.1%甲酸),流速为0.3 mL/min.采用电喷雾质谱检测,以正离子模式5 min完成质谱分析.实验结果表明,三聚氰胺在水产品中的检测限为0.05 mg/kg,在0.05～0.50 mg/kg添加水平时的加标回收率为63%～90%,测定结果的相对标准偏差均小于7.2%(n=6).     

色谱-质谱联用技术测定化妆品中25种邻苯二甲酸酯

建立了乳液、霜、水以及油类化妆品中25种邻苯二甲酸酯类化合物的气相色谱-质谱和液相色谱-质谱测定方法。不同基质样品经不同方法净化处理后,采用气相色谱-质谱或液相色谱-质谱进行测定。气相色谱-质谱法采用DB-5MS毛细管色谱柱(30 m,250 mm×0.25μm),程序升温,选择离子模式同时测定21种邻苯二甲酸酯类化合物。液相色谱-质谱采用MN EC-C18色谱柱(4.6×100 mm,2.7μm),以甲醇和0.1%甲酸为流动相,梯度洗脱,流速0.7 mL/min,采用电喷雾电离(ESI+),多反应监测(MRM)模式同时测定24种邻苯二甲酸酯类化合物。25种邻苯二甲酸酯类化合物的线性关系良好,相关系数均大于0.999,回收率实验结果为89.3%~105.6%,RSD为0.4%~4.0%,检出限均小于0.3 mg/kg。方法适用于化妆品中邻苯二甲酸酯类化合物的全面筛查。     

气相色谱-负化学电离质谱测定蔬菜中啶虫丙醚的残留量

建立以固相萃取净化和气相色谱-负化学质谱(GC/NCI/MS)技术快速测定蔬菜中啶虫丙醚残留量的方法。经乙腈提取,共提物中的基体杂质经PSA/SAX固相萃取柱去除,用负化学源质谱检测,灵敏度选择性高于气相色谱-电子轰击源质谱。目标农药的平均回收率为87.0%～91.0%,平均相对标准偏差为6.45%～6.80%(n=7),方法的检出限为1μg/kg。     

快速溶剂萃取-气相色谱/质谱联用测定塑料桌布中的邻苯二甲酸酯

采用快速溶剂萃取-气相色谱/质谱联用法(ASE-GC/MS)和超声波萃取-气相色谱/质谱联用法(USE-GC/MS)测定了塑料桌布中的邻苯二甲酸酯.结果表明:ASE-GC/MS的测量精度优于USE-GC/MS,后者测量值大约为前者的五分之四;ASE-GC/MS的回收率为89.0%～95.5%,相对标准偏差为4.3%～1...     

柱前衍生高效液相色谱-质谱法测定水稻中尼克烟酰胺含量

建立了柱前衍生高效液相色谱-质谱联用(HPLC-MS)测定水稻中尼克烟酰胺含量的方法.样品中尼克烟酰胺经水提取后,与9-芴甲基氯甲酸酯(FMOC-Cl)衍生,采用液相色谱质谱联用仪测定.系统研究了衍生剂浓度和衍生介质等条件对衍生效率的影响.通过优化流动相酸度和梯度洗脱等条件,提高了方法灵敏度.尼克烟酰胺在0.1～5.0 mg/L范围内呈良好的线性关系(r=0.9983),对水稻的根、茎、叶及大米的标准加入实验表明,方法的添加回收率在72.0%～89.2%之间; 相对标准偏差为2.3%～9.6%; 方法检出限为0.05 mg/kg.方法简便、准确可靠,可以满足水稻中生理水平尼克烟酰胺的定性定量分析.     

气质联用法测定复合食品包装袋中的二氨基甲苯

建立复合食品包装袋中二氨基甲苯气相色谱一质谱测定方法.样品用4%乙酸提取,加三氟乙酸酐进行衍生化,用气相色谱-质谱联用仪测定.二氨基甲苯含量在0. 002～0. 05μg/mL范围内与离子蜂面积呈良好的线性关系,相关系数r=0. 9998,检出限低于0. 0004 mg/L.测定结果的相对标准偏差为2. 98%～5. 50%(n=6),加标回收率为82%～92%.该方法快速、灵敏、测定结果准确.     

高效液相色谱-串联质谱法测定猪尿中秋水仙碱

提出了猪尿中秋水仙碱的液相色谱-串联质谱检测方法。采用pH8.0磷酸盐缓冲溶液碱化5mL尿样,用乙酸乙酯提取两次,合并提取液,于40℃吹氮蒸干,用2 mL流动相溶解残渣。在色谱分离中选用Sunfire C_(18)色谱柱,流动相为甲醇-2mmol·L~(-1)乙酸铵溶液(含0.1%甲酸)混合溶液(40+60),流量为0.2mL·min,进样量为10μL。质谱测定中采用电喷雾正离子模式离子化、多反应监测模式测定秋水仙碱,外标法定量。猪尿中秋水仙碱在1～50μg·L~(-1)内呈线性,测定下限(10S/N)为0.2μg·L~(-1),方法的回收率为90%～100%,相对标准偏差(n=6)小于9.0%。     

固相萃取-液相色谱-串联质谱法测定水果和土壤中四螨嗪残留量

建立了水果和土壤样品中四螨嗪的液相色谱-电喷雾串联质谱检测方法。水果或土壤样品用丙酮提取,经弗罗里硅土柱净化,以Agilent ZORBAX SB-C18色谱柱分离,以电喷雾电离串联质谱正离子多反应监测模式进行测定。对四螨嗪在水果和土壤中在4个不同添加水平下的回收率进行了测定,结果表明,四螨嗪在柑橘(全果)中的添加回收率为86.9%～93.1%(RSD为7.4%～9.4%),在苹果中的添加回收率为84.1%～95.1%(RSD为5.9%～9.7%),在葡萄中的添加回收率为88.8%～93.7%(RSD为8.0%～10.1%),在梨中的添加回收率为88.6%～96.1%(RSD为7.0%～10.2%),在土壤中的添加回收率为83.0%～96.8%(RSD 6.7%～12%)。该方法满足农药残留检测要求,适用于水果和土壤中四螨嗪残留的检测。     

固相萃取-液相色谱-串联质谱法同时测定尿液中9种多环芳烃代谢物

建立了固相萃取-液相色谱-串联质谱同时测定尿中2-羟基萘、1-羟基萘、2-羟基芴、3-羟基菲、1-羟基芘等9种多环芳烃代谢物的液相色谱-串联质谱测定方法。尿样中结合态的多环芳烃代谢物在β-葡萄糖苷酸酶-芳基硫酸酯酶缓冲液(pH 5.0)作用下,于37℃水浴中避光水解4 h后,以C18固相萃取小柱富集、净化,以甲醇洗脱,采用Waters Symmetry C18色谱柱,流动相为乙腈-0.2%氨水(72∶27,V/V)等度淋洗分离后进入质谱测定。在喷雾电压4 kV,毛细管温度300℃下,以3-羟基菲13C为内标,采用SRM模式负离子扫描方式测定,内标法定量。9种多环芳烃代谢物在尿中的线性范围为0.90～100μg/L;相关系数为0.9970～0.9990;回收率为79.0%～119.8%;相对标准偏差为4.3%～12.4%;检出限为0.04～0.90μg/L;结果表明,本方法可用于尿中9种多环芳烃代谢物的测定。     

全自动在线顶空固相微萃取-气相色谱-串联质谱法测定鱼塘投毒案件水样中硫丹和硫丹硫酸酯

鱼塘水样采用全自动在线顶空固相微萃取进行萃取:萃取温度为75℃;萃取时间为60min;氯化钠加入量为0.3kg·L~(-1);样品体积为2.0mL。采用气相色谱-串联质谱法测定水样中硫丹(α-硫丹、β-硫丹)和硫丹硫酸酯的含量,在气相色谱分离中采用DB-5ms毛细管色谱柱,在串联质谱分析中采用多反应监测模式。α-硫丹、β-硫丹和硫丹硫酸酯的质量浓度在一定范围内与其对应的峰面积呈线性关系,检出限(3S/N)为0.001～0.015μg·L~(-1),测定下限(10S/N)为0.003～0.050μg·L~(-1)。以空白水样为基体进行加标回收试验,所得回收率为83.6%～117%,测定值的日内相对标准偏差(n=6)为2.2%～18%,日间相对标准偏差(n=3)为4.2%～18%。     

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.