气相色谱-质谱法测定肝脏组织中盐酸克伦特罗和盐酸菜克多巴胺

建立了同时测定动物肝组织中盐酸克伦特罗和盐酸莱克多巴胺残留量的固相萃取-气相色谱-质谱分析方法。动物肝组织样品在碱化的条件下用乙酸乙酯和异丙醇混合溶剂提取，提取液浓缩后用乙酸乙酯溶解，然后再用稀盐酸反萃取去除脂肪，调pH值后经SCX固相萃取（SPE）柱净化，洗脱液经氮气吹干后经双三甲基硅基三氟乙酰氨（BSTFA）衍生，采用选择离子模式（盐酸克伦特罗：86、212、262、277，盐酸莱克多巴胺：163、192、234、250）进行测定，外标法定量。盐酸克伦特罗和盐酸莱克多巴胺的检出限分别为0．30和1．00μg／kg。盐酸克伦特罗添加浓度在1．0～5．0μg／kg范围内，添加回收率为77．4％～88．3％；相对标准偏差（RSD）为3．1％～5．1％；盐酸莱克多巴胺添加浓度在4．0～20．0μg／kg，添加回收率为69．8％～82．1％；相对标准偏差（RSD）为3．5％～4．9％；衍生物的峰面积与被测物浓度分别在0．003～1．00mg／L和0．012～4．00mg／L范围内呈良好的线性关系，线性回归系数均大于0．999。     

固相萃取-气相色谱-质谱法测定猪组织中沙丁胺醇残留量

建立了动物组织中沙丁胺醇残留量固相萃取-气相色谱-质谱分析方法.动物组织样品经过葡萄糖醛甙酶酶解后调节pH至9.5,然后用异丙醇/乙酸乙酯混合溶剂液液分配去除杂质,旋转浓缩后用乙酸铵缓冲溶液溶解经SCX固相萃取(SPE)柱净化,洗脱液经氮气吹干后用双三甲基硅基三氟乙酰氨(BSTFA)衍生,采用选择离子模式(86、350、369、440)进行测定,外标法定量.检出限为0.10 μg/kg.在添加浓度0.5～5.0 μg/kg范围内,平均添加回收率在66.4%～82.4%,相对标准偏差(批内)(CV)在3.5%～5.9%之间;批间(CV)在2.2%～4.8%之间.衍生物的峰面积与样品浓度在0.002～0.50 mg/L范围内呈良好的线性关系,线性回归系数大于0.999.     

反相高效液相色谱／质谱法同时测定鸡肉中5种喹诺酮药物残留

采用反相高效液相色谱／四级杆串联质谱（RP-HPLC／MS／MS）同时测定鸡肉中的5种喹诺酮药物（quinolones，QNs）。均质后的鸡肉样品采用磷酸盐缓冲溶液和乙腈的混和溶液提取。提取液经正己烷液-液分配（LLP）去除脂肪后，用C18固相萃取（SPE）柱净化，氨化甲醇洗脱，洗脱液用氮气吹干，流动相定容后，分析物采用LC／MS／MS电喷雾电离（ESI），正离子，多反应监测（MRM）模式检测，外标法定量。在添加浓度2．5～10μg/kg范围内，5种QNs的回收率在79．8％～95．1％之间；相对标准偏差（RSD）均小于11．7％。环丙沙星、丹诺沙星、恩诺沙星检出限（LOD）为0．5μg／kg，沙托沙星为1．0μg／kg，氟甲喹为0．1μg／kg。     

固相萃取-气相色谱法测定动物组织中盐酸克伦特罗残留量

建立了固相萃取-气相色谱分析动物组织中盐酸克伦特罗残留量的方法．采用固相萃取,分离富集动物组织中的盐酸克伦特罗．肉样的加标回收率在70％～80％;最低检出限为1μg／kg．盐酸克伦特罗的硅烷化衍生产物,采用气相色谱(ECD检测器)检测,其衍生物的峰面积与样品浓度在0．005～1．0μg／mL范围内呈良好的线性关系,线性回归系数大于0．999．     

气相色谱-负化学源质谱联用法测定菊酯类农药

通过固相萃取-气相色谱-负化学离子源质谱技术建立了11种拟除虫菊酯类农药残留的检测方法，并应用于茶叶农残检测。样品经乙酸乙酯提取后，用串联的活性炭和中性氧化铝固相萃取柱选择性地富集茶叶中待测组分，再由气相色谱-负化学离子源质谱分时段选择离子监测技术进行测定。方法简单快速，一次进样就能得到11种菊酯残留结果；准确度和精密度高，在0．016μg／kg、0．032μg／kg和0．064μg／kg3个添加水平下的回收率在70％～110％之间，CV≤7．4％；选择性好，消除了色素和其它杂质干扰；灵敏度高，检出限低，除了氯菊酯为10μg／kg外，其它菊酯检出限都在μg/∥kg级，七氟菊酯则达到了0．02μg／kg。     

固相萃取-液相色谱／串联质谱法测定黄酒中的甜蜜素

建立了黄酒中甜蜜素残留的固相萃取-液相色谱／串联质谱法（SPE—LC／MS／MS）测定方法。黄酒样品用水稀释后,弱阴离子（WAX）固相萃取小柱净化,氨化甲醇洗脱。采用HypersilGold C18色谱柱（150mm×2．1mm,5μm）,乙腈-0．1％甲酸水溶液为流动相,以电喷雾离子源负离子模式（MRM）定性、定量测定甜蜜素。甜蜜素在10～500μg／L范围内峰面积与质量浓度呈线性关系,相关系数为0．9995。取有代表性的阴性样品进行添加回收试验,在0．5—5．0mg／L范围内,回收率为81．1％-88．2％,相对标准偏差为3．65％～5．21％,方法的定量检测限为0．5mg／L。该方法净化效果好,检测灵敏度高,能同时完成黄酒中甜蜜素的定量和定性分析。     

植物油中苯并芘含量测定研究

为建立固相萃取-液相色谱法测定植物油中苯并芘的检验方法,将植物油中的苯并芘用中性氧化铝固相萃取小柱萃取和净化后用反相色谱柱分离,荧光检测器进行了检测。结果表明,苯并芘质量浓度在0．001～0．1μg／mL范围内与峰面积具有良好的线性关系,相关系数r=0．9999,检测限为0．4μg／kg,回收率在88．1％～94．2％之间,RSD为2．42％,操作简便,对样液的净化效果好,结果准确可靠。     

同位素稀释高效液相色谱串联质谱法测定猪肝中地塞米松和倍他米松残留量

建立了同位素稀释高效液相色谱串联质谱法测定猪肝中地塞米松和倍他米松残留量的分析方法。样品经酶解后用乙腈提取,再经C18固相萃取和碳酸钠溶液液液萃取净化,净化后的样品经氮气吹干后用流动相溶解。采用Hypercarb C18柱,以乙腈-水-甲酸(95∶5∶0.5,V/V)混合溶液为流动相,进行高效液相色谱串联质谱分析,同位素内标法定量分析。地塞米松和倍他米松的检出限为别为0.12和0.14μg/kg,定量限分别为0.42和0.47μg/kg。在添加浓度0.75～2.0μg/kg范围内,平均添加回收率为97.3%～111%,批内和批间相对标准偏差(RSD)分别为1.85%～5.65%和2.78%～7.98%。待测物定量离子对峰面积与内标物峰面积比值与标样浓度在10～500μg/L范围内呈良好的线性关系,线性回归系数大于0.9997。     

高效液相色谱法测定鸡蛋中呋喃唑酮的残留量

采用基体固相扩散和固相萃取相结合的技术,对鸡蛋中呋喃唑酮残留进行了提取和净化处理,建立了高效液相色谱法检测鸡蛋中呋喃唑酮残留量的方法。对呋喃唑酮在C18固定相和硅胶固相萃取柱上的保留行为进行了研究。采用液相色谱分离,外标法定量,呋喃唑酮标准溶液的峰面积与样品浓度在5μg／L～2．5mg／L范围内呈良好的线性关系,线性回归系数大于0．9999。鸡蛋样品中呋喃唑酮不同加入量的平均回收率在80．2％～91．1％;相对标准偏差在2．0％～9．5％;最低检出限为10μg／kg。分析方法具有良好的重现性．批内、批间定量结果的相对标准偏差均小于10％。     

固相微萃取-高效液相色谱联用测定环境水样中双酚A的自由溶解态浓度

应用可忽略耗损固相微萃取与高效液相色谱联用技术测定了环境水样中双酚A的自由溶解态浓度。为了获得高的灵敏度并减小环境因素（如温度和搅拌等）的影响,采用商品化固相微萃取纤维CW／TPR进行平衡采样。在环境水样常见pH（5～8）、缓冲容量（5～200mmol／L）和盐度（0～500mmol／L）条件下,4h可以达到萃取平衡。100mL样品足以避免样品耗损。以配制在250mmol／L NaCl和125mmol／L磷酸盐溶液（pH6．4）中的双酚A标准溶液进行校准,可以将缓冲液（0～200mmol／L）、盐度（0～500mmol／L）和pH（5．7～8．5）的影响控制在15％偏差范围以内。如需更准确的测定,也可以对样品pH值的影响加以校正。pH为6．4时,方法的线性范围为0．1～250μg／L,检出限为0．03μg／L,相对标准偏差（5μg/L,n=3）为1．1％。采用本方法测定了污水处理厂排水口的双酚A的自由溶解态浓度。     

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.