液相色谱–串联质谱法测定水果及其制品中氯吡脲残留量

建立了液相色谱–三重四极杆串联质谱测定水果及其制品中氯吡脲的方法。样品经乙腈提取,氨基固相萃取小柱净化后,用ZORBAX Extend-C18柱(150 mm×2.1 mm,5μm)分离,以甲醇–水为流动相等度洗脱,采用多反应监测正离子模式检测,外标法定量。氯吡脲的质量浓度在4.0~200.0 ng/m L范围内线性良好,相关系数大于0.999,在5.0,10.0,20.0μg/kg 3个添加水平下,氯吡脲的平均加标回收率为86%~92%,测定结果的相对标准偏差为5.3%~7.6%(n=5),方法定量下限为2.0μg/kg。方法灵敏度高,操作简便,定量准确,可满足梨、柑桔、黄桃等水果及其罐头制品中氯吡脲残留的检测与确证需要。     

同位素稀释高效液相色谱-串联质谱法测定面粉及面制品中的联二脲

建立了面粉及其制品中联二脲的同位素稀释高效液相色谱-串联质谱检测方法。采用纯水超声提取,含油脂的样品加正己烷脱脂,所得样液进行高效液相色谱-串联质谱测定。以乙腈与纯水为流动相,梯度洗脱,经Waters XBridge BEH Amide(3.5μm,4.6 mm×150 mm)色谱柱分离,MS/MS采用电喷雾电离正离子(ESI+),多反应监测(MRM)模式检测,同位素内标法定量。方法的线性范围为0.2~100μg/L,相关系数为0.999 9;在面粉、馒头、面包、油条和面条5种基质中的平均加标回收率为82.0%~113.6%,相对标准偏差(RSD)为2.1%~9.3%;方法定量下限(LOQ)为20μg/kg。应用该方法对136份市售的面粉及面制品进行检测,在42份样品中检出联二脲,检出率为30.88%。其中面粉检出4份,含量为43.7~564μg/kg;馒头未检出;面条检出2份,分别为70.8μg/kg与9 840μg/kg;油条检出1份,含量为2 480μg/kg;面包表层检出15份,含量为27.4~8 730μg/kg;面包内芯检出20份,含量为64.3~18 100μg/kg。该方法操作简单、灵敏快速、准确可靠,适用于面粉及其制品中联二脲的测定。     

超声萃取/气相色谱-质谱联用法同时测定皮革及其制品中21种有害有机溶剂的残留量

建立了气相色谱-质谱/选择离子监测方法,对皮革及其制品中21种有害有机溶剂的残留量进行了同时测定。该方法以乙酸乙酯为萃取溶剂,45℃下超声萃取皮革及其制品中残留的有害有机溶剂,萃取液经固相萃取柱净化后进行气相色谱-质谱/选择离子监测法分析,外标法定量。结果表明,在信噪比(S/N)为10的条件下,乙二醇二丁醚(EGDBE)、三乙二醇二甲醚(TEGDME)、二乙二醇单丁醚(DEGBE)和三乙二醇单乙醚(TEGEE)的定量下限均为50μg/kg,N-甲基乙酰胺(MA)和N-甲基甲酰胺(MF)的定量下限均为150μg/kg,甲酰胺的定量下限为300μg/kg,其余14种组分的定量下限均为100μg/kg。在3个不同加标水平下,方法的平均加标回收率为82.1%~94.9%,相对标准偏差(RSD,n=9)为1.6%~4.8%。该方法简单快捷,灵敏度高,可用于皮革及其制品中有害有机溶剂残留量的测定。     

固相萃取/~(18)O标记高氯酸根稀释高效液相色谱-串联质谱法测定水果中的高氯酸盐

建立了水果中高氯酸盐的高效液相色谱-串联质谱分析检测方法。样品采用1%乙酸提取,C18固相萃取柱净化,Waters IC-Pak Anion HR(4.6 mm×75 mm)色谱柱洗脱,流动相为乙腈-100 mmol/L乙酸铵溶液(体积比60∶40),流速0.7 m L/min;液相色谱-三重四极杆质谱联用技术-电喷雾负离子监测模式检测,采用18O标记高氯酸根离子作为内标进行基质校正,内标法定量。结果表明:高氯酸盐在0.1~10.0μg/L范围内线性关系良好,定量下限为1.0μg/kg;在1.0,2.0,10μg/kg 3个加标水平下的回收率为92.5%~110%,相对标准偏差(RSD)为1.4%~5.4%。实际样品检测表明该方法准确可靠,适合于水果中高氯酸盐的测定。     

固相萃取/液相色谱-串联质谱法测定果蔬中草铵膦的残留量

建立了果蔬中草铵膦残留量的液相色谱-串联质谱(LC-MS/MS)分析方法。样品经水提取、二氯甲烷除去脂溶性杂质,强阳离子固相萃取小柱净化,9-芴甲基氯甲酸酯(FMOC-Cl)衍生后,以C18色谱柱(4.6 mm×50 mm,1.8μm)进行分离,5 mmol/L乙酸铵水溶液(含0.1%甲酸)-乙腈(含0.1%甲酸)作为流动相梯度洗脱,电喷雾正离子模式电离(ESI+),多反应监测模式(MRM)检测,内标法定量。方法在0~200μg/L浓度范围内线性关系良好,相关系数(r2)大于0.995。方法检出限为10μg/kg,定量下限为20μg/kg。在不同食品基质中,草铵膦在20,200,500μg/kg加标水平下的平均回收率为80.8%~102.2%,相对标准偏差(RSD)为1.8%~7.9%。该法采用同位素内标定量,有效地消除了样品基质效应,灵敏度高、准确度好,适用于果蔬中草铵膦残留量的监控测定。     

高效液相色谱测定浓缩苹果汁展青霉素的残留量

报道采用高效液相色谱(HPLC)法分析浓缩苹果汁中展青霉素的含量。果汁样品先经纯水稀释,再用乙酸乙酯提取,通过净化、浓缩,用甲醇/水(1∶1,V/V)定容后,进行HPLC检测。色谱柱为资生堂MG-ⅡC18柱,采用等度洗脱,流动相为甲醇、水、乙酸-乙酸钠盐缓冲液(pH=4.6);采用可变波长检测器(VWD)在276 nm波长检测。展青霉素在0.02~1.0μg/mL范围内与其峰面积呈良好的线性关系,其相关系数(R2)为0.9965。果汁样品中不同水平标准加入回收率在69.82±1.64%~87.54±3.61%范围;展青霉素在样品中残留量检测的定量限为50μg/L。     

高效液相色谱-电喷雾串联质谱法同时测定水产品中硝基咪唑类化合物及其代谢物残留

建立了高效液相色谱-电喷雾串联质谱(HPLC-ESI MS/MS)快速测定水产品中硝基咪唑类兽药甲硝哒唑(MNZ)、洛硝哒唑(RNZ)、迪美硝唑(DMZ)及其代谢物羟基甲硝唑(MNZOH)、羟基二甲硝咪唑(HMMNI)残留量的分析方法。样品在弱碱性条件下(磷酸二氢钠缓冲液,p H 8.0)经甲醇-丙酮(3∶1)混合液提取,乙酸乙酯萃取和乙腈正己烷分配脱脂净化;以0.1%甲酸水溶液和0.1%甲酸乙腈溶液为流动相,梯度洗脱,Agilent ZORBAX SB C18RRHD(100 mm×2.1 mm,1.8μm)色谱柱分离;多反应监测正离子模式扫描,同位素稀释内标法定量。结果表明,5种目标分析物在0.25~50μg/L范围内线性关系良好,相关系数为0.998 6~0.999 7;定量下限(S/N≥10)均可达到0.1μg/kg。各基质在0.1,0.5,10.0μg/kg加标水平的回收率为70.7%~105.1%,相对标准偏差为1.7%~8.1%。该方法操作快速、高效、定量重复性好,适用于水产品中硝基咪唑类药物残留的检测。     

同位素稀释/液相色谱-串联质谱测定婴幼儿配方奶粉中脂溶性维生素

采用液相色谱-串联质谱(LC-MS/MS)结合同位素稀释定量方法,建立了婴幼儿配方奶粉中维生素A、维生素D_2、维生素D_3、维生素E和维生素K15种脂溶性维生素同时测定的分析方法。样品经脂肪酶酶解,氢氧化钾-乙醇皂化,石油醚提取,乙醇定容,经BEH C18色谱柱(100 mm×2.1 mm,1.7μm)分离后,以甲醇(甲酸0.02%)-0.1%甲酸溶液为流动相,0.4 m L/min梯度洗脱,采用大气压化学电离,正离子多反应监测模式测定。5种脂溶性维生素在一定浓度范围内具有良好的线性关系,相关系数(r2)大于0.99,加标回收率为83.8%~113.7%,相对标准偏差(RSD,n=6)为1.2%~10.1%,定量下限(LOQ)为0.5~10μg/100g。该方法简便、快速、灵敏、准确,可满足配方奶粉中脂溶性维生素的检测要求。     

亲水相互作用色谱-串联质谱法同时测定动物组织中金刚烷胺与利巴韦林

采用亲水相互作用色谱-串联质谱技术,建立了同时测定动物组织中金刚烷胺和利巴韦林的方法。样品加入同位素内标,采用20 g/L三氯乙酸提取,经磷酸酯酶酶解,PBA固相萃取小柱净化后,采用HILIC色谱柱(100 mm×2.1 mm,3μm)分离,以5 mmol/L乙酸铵水溶液(含0.1%甲酸)-乙腈为流动相梯度洗脱,采用电喷雾离子源串联质谱,在正离子扫描方式下以多反应监测(MRM)模式检测,内标法定量。在优化条件下,金刚烷胺和利巴韦林在0.5~5.0μg/L质量浓度范围内线性关系良好,定量下限分别为1.0μg/kg和2.0μg/kg。在鸡肉和鸡肝样品中,金刚烷胺和利巴韦林在3个加标水平(分别为1.0、2.0、5.0μg/kg和2.0、5.0、10.0μg/kg)下的平均回收率为89.2%~109%,相对标准偏差为2.0%~9.3%。该方法准确可靠、方便快捷,适用于动物组织中金刚烷胺和利巴韦林的同时定量分析。     

固相萃取/液相色谱-串联质谱法同时测定面膜类化妆品中非法添加的53种糖皮质激素

建立了固相萃取/液相色谱-串联质谱法(SPE/LC-MS/MS)同时测定面膜类化妆品中53种糖皮质激素的方法。样品经水分散后,加入甲醇涡旋提取,提取液用水稀释后,采用Cleanert PEP(60 mg,3 m L)固相萃取小柱净化。待测物经Waters CORTECS C18+(100 mm×2.1 mm,2.7μm)色谱柱分离,在电喷雾离子源的正离子模式下以动态多反应监测(DMRM)模式采集数据并作定性筛查和定量分析。53种药物在相应的浓度范围内线性关系良好,相关系数均大于0.99,在3个不同浓度加标水平下,平均回收率为66.8%~106.3%,相对标准偏差(RSD)为3.9%~13.2%,检出限(LOD,S/N≥3)和定量下限(LOQ,S/N≥10)分别为3μg/kg及10μg/kg。该方法操作简便、定性可靠、定量准确、灵敏度高,适用于化妆品中非法添加糖皮质激素的定性确证和准确定量。     

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.     

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.     

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.     

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.