高效液相色谱-串联质谱法检测羊奶中乙酰孕激素多残留研究

建立了高效液相色谱-串联质谱同时测定羊奶中醋酸氟孕酮、醋酸美仑孕酮、醋酸甲地孕酮、醋酸氯地孕酮4种乙酰孕激素的多残留检测方法.试样用乙腈提取,经冷冻离心除脂后,用C18固相萃取柱进一步净化,液相色谱分离,采用多反应监测正离子模式对4种乙酰孕激素进行同时定性定量分析,在0.5～20μg/L范围内,4种乙酰孕激素与其对应峰面积的线性关系良好,相关系数均不低子0.999 6.羊奶中醋酸氟孕酮、醋酸氯地孕酮的检出限为0.2 μg/kg,醋酸美仑孕酮、醋酸甲地孕酮的检出限为0.1μg/kg,定量下限均为0.5 μg/kg.在羊奶中添加0.5、1、2、10 μg/kg水平的药物进行加标回收试验,4种乙酰孕激素的平均回收率均在87％ ～ 96％之间,相对标准偏差为4.5％～9.1％.该方法灵敏、准确,适用于羊奶中乙酰孕激素残留的分析检测.     

高效液相色谱-串联质谱法同时检测鸡肉和鸡蛋中合成类固醇类激素和糖皮质激素

建立了鸡肉和鸡蛋中合成类固醇类激素(睾酮、甲基睾酮、群勃龙、勃地龙、诺龙、美雄酮、司坦唑醇、丙酸诺龙、丙酸睾酮及苯丙酸诺龙)和糖皮质类激素(泼尼松、泼尼松龙、地塞米松、氟氢可的松、甲基泼尼松、倍氯米松及氢化可的松)多残留的液相色谱-串联质谱(LC-MS/MS)检测方法.样品经乙腈超声提取,正己烷脱脂净化,以甲醇-甲酸水溶液为流动相,经C18柱分离后进行LC-MS/MS选择反应监测模式下的定性及定量分析.合成类固醇类激素采用正离子模式检测,糖皮质激素则采用负离子模式检测,正、负离子化模式一次进样同时检测.类固醇类和糖皮质类激素的定量检出限为0.5 μg/kg.在0.5、 1.0和5.0 μg/kg 3种浓度添加水平,上述激素的平均回收率为73.4%～108.9%;相对标准偏差为3.4%～13.4%.可实现样本灵敏、准确地定性定量分析.     

气相色谱-串联质谱法同时测定食品中18种邻苯二甲酸酯

建立了凝胶色谱(GPC)净化、气相色谱-串联质谱(GC-MS/MS)多反应监测模式同时测定油脂食品中18种邻苯二甲酸酯的方法.优化了前处理和分析条件,样品加标浓度在2 mg/kg时的回收率在80％～120％之间,相对标准偏差均小于10％,检出限为5 μg/kg,定量限为20 μg/kg,在20～1 000 μg/mL范围内,具有良好的线性关系,能够满足大量样品快速准确分析的需要.     

液相色谱-串联质谱法测定牛奶中6种甲状腺拮抗剂残留

建立了牛奶中甲巯咪唑、硫脲嘧啶、甲基硫氧嘧啶、丙基硫氧嘧啶、苯基硫氧嘧啶和2-巯基苯并咪唑6种甲状腺拮抗剂残留的液相色谱-串联质谱分析方法.样品经乙腈沉淀蛋白后,上清液以衍生剂4-碘苄溴在pH=8.0下衍生2h,衍生液调节至pH=3.0,以乙酸乙酯提取.溶剂挥干后以20％甲醇复溶,Oasis HLB固相萃取小柱净化,4 mL 50％甲醇-乙腈溶液洗脱,Luna C18色谱柱分离,乙腈和5 mmol/L乙酸铵溶液(含0.2％甲酸)进行梯度洗脱,电喷雾正离子模式电离(ESI+),多反应监测(MRM)模式检测,内标法定量.结果表明:牛奶中6种目标物在优化条件下分离良好,响应值高,峰形尖锐对称,在5 ～ 100 μg/kg范围内呈良好的线性关系,相关系数r2均大于0.99;检出限为0.14～0.32 μg/kg,定量限为0.48～1.1 μg/kg;10,20和50 μg/kg添加水平的平均回收率为82.8％～ 113.6％,相对标准偏差2.4％～14.3％.     

Determination of Chlormequat and Mepiquat Residues in Seeding Cultivation Using Accelerated Solvent Extraction- Solid-phase Extraction/Ultraperformance Liquid Chromatography- Tandem Mass Spectrometry

研究建立了一种加速溶剂萃取-固相萃取/超高效液相色谱-串联质谱法(SPE - UPLC - MS/MS)测定育苗基质中矮壮素和助状素的分析方法.样品采用快速溶剂萃取仪( ASE)提取,经CBA弱阳离子交换柱净化后,在亲水作用色谱柱上用SeQuant ZLC- HILIC MEKCK色谱柱进行分离;电喷雾正离子(ESI+)模式电离,多反应监测(MRM)模式检测.矮壮素和助状素的质量浓度在0.2～ 10 μg/kg范围内线性关系良好(r2＞0.999),在2、5、10 μg/kg加标水平的平均回收率分别为77％～ 106％和97％ ～111％,相对标准偏差(RSD)分别为7.3％ ～ 21.7％和5.6％～1 6.1％,检出限(LOD)均为0.02 μg/kg,定量下限(LOQ)均为0.1 μg/kg.该方法简便、快速、灵敏、准确,适合育苗基质中矮壮素和助状素残留的确证和定量测定.     

猪肉组织中阿维菌素类药物残留的高效液相色谱-串联质谱法测定

建立了以高效液相色谱-串联质谱同时检测猪肉中阿维菌素、多拉菌素及伊维菌素3种大环内酯类药物残留的分析方法.样品用乙腈提取,经C18柱净化后,高效液相色谱等度分离,采用多反应监测模式,对3种药物在猪肉组织中的残留同时进行定性、定量分析.3种药物在5 ～250 μg/L范围内线性良好(r0.999),在5、10、20 μg/kg添加水平下,3种药物的回收率在84% ～103%,相对标准偏差为1.4% ～12.9%.3种药物的检出限(S/N=3)均达0.5 μg/kg.     

QuEChERS-高效液相色谱-串联质谱法测定植物源食品中环磺酮残留

建立了高效液相色谱-串联质谱法(HPLC-MS/MS)测定植物源食品中环磺酮残留量的分析方法.样品经改进的QuEChERS方法一步完成萃取净化,经酸化乙腈(含0.1％(V/V)甲酸的乙腈)提取,经石墨化碳黑(GCB)净化,提取液经离心后直接过膜上机检测.HPLC-MS/MS方法以0.1％(V/V)甲酸-乙腈为流动相,在0.25 mL/min流速下梯度洗脱,采用C18色谱柱进行液相色谱分离,电喷雾正离子电离(ESI+),多重反应监测模式(MRM)检测,基质匹配外标法进行定量分析.结果表明,在10种基质(玉米、大米、小麦、葡萄、苹果、葡萄干、枸杞、西红柿、黄瓜、白菜)中,环磺酮在0.5 ～ 100.0 ng/mL范围内线性关系良好,相关系数均大干0.996;方法定量限(S/N≥10)为1.0 μg/kg;在1.0,2.0和10.0μg/kg添加水平下,环磺酮的平均回收率为82.0％ ～111.8％,相对标准偏差为3.0％～14.9％.本方法高效快捷,灵敏度、准确度和精密度均符合农药残留检测要求.     

超高效液相色谱-串联质谱联用法对水产品中亚甲基蓝及其代谢物残留的检测

建立了超高效液相色谱-串联质谱同时检测水产品中亚甲基蓝及其代谢物天青A、天青B、天青C残留的方法.试样中的残留药物采用离子对试剂提取,正己烷脱脂净化,超高效液相色谱-串联质谱法测定.对前处理及液相色谱分离条件进行了探讨与优化.4种分析物在0.25 ～50 μg/L范围内线性关系良好,相关系数均大于0.999,方法定量下限可达0.5 μg/kg.在0.5、1.0、5.0 μg/kg范围内,平均加标回收率为80% ～91%;相对标准偏差为6.38% ～9.41%.方法灵敏、稳定,可满足水产品中亚甲基蓝及其代谢物残留的检测与确证及对药物动力学研究的需要.     

同位素稀释液相色谱-串联质谱法测定动物性食品中的双酚A、壬基酚及辛基酚

建立了动物性食品肉、蛋和奶中双酚A、壬基酚和辛基酚的超高效液相色谱-串联质谱( UPLC-MS/MS)检测方法.比较了固相萃取法(SPE)和凝胶渗透色谱法(GPC)两种前处理技术,探讨了前处理过程中目标化合物背景污染的来源.最终采用乙酸乙酯-环己烷(1∶1,V/V)超声提取,经GPC净化后进行超高效液相色谱串联质谱分析.3种目标化合物的线性范围为0.25～1600 μg/L,相关系数R2＞ 0.999;对肉和鸡蛋样品,方法的定量限( LOQ)为0.2μg/kg;奶粉样品的LOQ为0.4 μg/kg.目标化合物在3个不同水平的加标回收率为85.9％～117.0％,RSD＜ 20％.应用本方法对市售动物性食品肉、蛋和奶进行了分析,壬基酚的检出率最高,含量为0.27～1357 μg/kg,此外还检出了双酚A.     

Determination of Four β2-Agonists Residues in Sausage by Matrix Solid-phase Dispersion and High Performance Liquid Chromatography- Tandem Mass Spectrometry

利用同位素稀释技术,建立了肉肠中4种β2-受体激动剂克伦特罗、莱克多巴胺、沙丁胺醇和特布他林的基质固相分散/高效液相色谱-串联质谱( MSPD/HPLC - MS/MS)分析方法.样品经C1s填料研磨,甲醇洗脱,提取物经酶解后,用MCX小柱净化,经高效液相色谱分离,在正离子多反应监测(MRM)模式下用电喷雾电离串联质谱测定,内标法定量.4种β2-受体激动剂在0.2～20.0 μg/L质量浓度范围内呈良好的线性关系,相关系数(r2)均大于0.990;沙丁胺醇和克伦特罗的检出限为0.10 μg/kg;莱克多巴胺和特布他林的检出限为0.15 μg/kg;方法的回收率为80％～ 109％,相对标准偏差小于10％.该方法简便快捷、灵敏度高,样品和溶剂用量少,可满足肉肠中4种β2-受体激动剂残留的快速检测.     

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.     

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.     

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.     

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.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.