超声萃取-免疫亲和柱净化-柱后光化学衍生高效液相色谱法同时测定蜂房药材中4种黄曲霉毒素

建立超声萃取-免疫亲和柱净化-柱后光化学衍生高效液相色谱同时测定蜂房药材中黄曲霉毒素B1、黄曲霉毒素B2、黄曲霉毒素G1、黄曲霉毒素G2含量的分析方法。样品经粉碎，过孔径为120μm筛后，采用70%甲醇溶液超声处理30 min，经免疫亲和柱净化、高效液相色谱分离、光化学柱后衍生，通过荧光检测器测定4种黄曲霉毒素的含量。黄曲霉毒素B1的线性范围为0.010 4～0.052 0 ng，相关系数为0.999 9；黄曲霉毒素B2的线性范围为0.003 8～0.019 0 ng，相关系数为0.999 8；黄曲霉毒素G1的线性范围为0.010 8～0.054 0 ng，相关系数为0.999 8；黄曲霉毒素G2的线性范围为0.003 8～0.019 0 ng，相关系数为0.999 8。4种黄曲霉毒素检出限分别为0.42、0.15、0.43、0.15μg/kg，测定结果的相对标准偏差不大于2.5%(n=6)，样品加标回收率为92.9%～96.9%。该方法操作简便，灵敏度高，可用于蜂房中黄曲霉毒素含量的测定。     

固相萃取净化/超高效液相色谱-串联质谱法测定养殖环境中地西泮及其代谢物

建立了固相萃取净化/超高效液相色谱-串联质谱(SPE/UPLC-MS/MS)同时测定养殖水和沉积物样品中地西泮及其3种代谢物的分析方法。水样经0.45μm玻璃纤维膜过滤,沉积物采用1%氨水-乙酸乙酯提取后,均通过混合型阳离子交换固相萃取(MCX SPE)柱富集净化。目标物用5%氨水-乙腈溶液洗脱后吹干,1 mL 40%乙腈水溶液溶解残渣,UPLC-MS/MS测定。经Phenomenex Kinetex C₁₈(100 mm×2.1 mm,1.7μm)色谱柱分离,乙腈和0.1%甲酸水溶液为流动相进行梯度洗脱。采用电喷雾正离子电离,多反应监测(MRM)模式下测定,内标法定量。4种目标物在0.1～100μg/L范围内的线性关系良好,相关系数(r²)大于0.999。水体和沉积物中的方法检出限分别为1.0～2.0 ng/L和0.02～0.05μg/kg,定量下限分别为2.0～5.0 ng/L和0.05～0.1μg/kg;平均加标回收率为90.2%～115%,相对标准偏差(RSD,n=6)为2.1%～9.6%。该方法灵敏度高,实用性强,可满足养殖环境中地...     

高效液相色谱-三重四极杆串联质谱测定谷物中T-2毒素和HT-2毒素

建立了快速分析谷物样品中T-2毒素和HT-2毒素的高效液相色谱-三重四极杆串联质谱( HPLC-MS/MS)分析方法.样品经乙腈-水(80:20,V/V)混合溶剂提取,免疫亲和柱净化后,采用HPLC-MS/MS测定.T-2毒素和HT-2毒素的检测线性范围均为0.20 ～20.00 μg/kg,定量下限为0.20 μg/...     

液相色谱-串联质谱法测定虾饲料中7种真菌毒素

建立了虾饲料中黄曲霉毒素B_1(AFB_1)、黄曲霉毒素M_1(AFM_1)、T-2毒素(T-2)、HT-2毒素(HT-2)、脱氧雪腐镰刀菌烯醇(DON)、赭曲霉毒素A(OTA)和玉米赤霉烯酮(ZEN)的液相色谱-串联质谱(LC-MS/MS)同时检测方法。样品中加入15 mL乙腈-水(体积比4∶1)和10 mL乙腈饱和正己烷,涡旋混匀,超声提取,MycoSpin~(TM)400多毒素净化柱净化后上机测定。采用Hypersil Gold (150 mm×2.1 mm,5μm)色谱柱进行分离,以甲醇-水(含0.03%氨水)为流动相梯度洗脱,在电喷雾电离模式下正、负离子同时扫描检测,基质匹配外标法定量。在优化条件下,7种真菌毒素的线性相关系数(r~2)均大于0.991,检出限为1.83～12.63μg/kg。在高、中、低3个加标水平下,各目标毒素的回收率为87.5%～116%,相对标准偏差为2.4%～18%。该法可为水产饲料中多种真菌毒素的同时检测提供参考。     

超高效液相色谱法快速测定发酵茶叶中的黄曲霉毒素

建立了用超高效液相色谱/紫外检测器测定发酵茶叶中黄曲霉毒素B1、B2、G1和G2的方法.用CH2Q2提取黄曲霉毒素,提取液经浓缩后,用LC-CN固相萃取小柱净化,超高效液相色谱测定.在浓度范围20～200μg/L(B1、G1),15～120μg/L(B2、G2)内具有良好的线性相关关系.黄曲霉毒素的回收率为81.4%～92.3%,相对标准偏差RSD 1.6%～4.2%.检出限为0.32μg/kg(B1、G1),0.18μg/kg(B2、G2)(S/N=3).     

免疫亲和柱净化、在线电化学衍生化高效液相色谱法检测花生中的黄曲霉毒素

 采用免疫亲和柱净化、在线电化学衍生化高效液相色谱法测定了花生中黄曲霉毒素（AFT）B 1,B2,G1和G2。以体积分数为80%的甲醇提取样品中的AFT,经免疫亲和柱净化洗脱 后,以Kobra Cell装置在线衍生,反相HPLC分离定量。4种毒素的分离在13 min内完成,检 出限均达到0.1 μg/kg。5次测定花生样品的RSD值为9.2%～15%;样品添加标样0.5 ～9.0 μg/kg,回收率为74.8%～97.3%。     

超高效液相色谱-串联质谱法测定牛奶中黄曲霉毒素M1

提出了超高效液相色谱-串联质谱法测定牛奶中黄曲霉毒素M₁含量的方法。样品经免疫亲和柱净化,用乙腈洗脱下来。以ACQUITY UPLC BEH C₁₈柱（2.1 mm×50mm,1.7μm）为分离柱,乙腈和水为流动相梯度淋洗,用串联质谱测定。采用电喷雾电离正离子模式进行多反应监测。黄曲霉毒素M₁的质量浓度在0.1～16.0μg·L^-1范围内与其峰面积呈线性关系,检出限（3S/N）为0.001 5μg·kg^-1,测定下限（10S/N）为0.005μg·kg^-1。方法用于分析牛奶样品,测得回收率在89.5%～101.5%之间,测定值的相对标准偏差（n=6）在2.8%～9.5%之间。     

Qu ECh ERS/LC-MS/MS法测定食品中7种真菌毒素

建立了食品中常见的黄曲霉毒素B1(AFB1)、黄曲霉毒素B2(AFB2)、黄曲霉毒素G1(AFG1)、黄曲霉毒素G2(AFG2)、赭曲霉毒素A(OTA)、赭曲霉毒素B(OTB)和赭曲霉毒素C(OTC) 7种真菌毒素的QuEChERS前处理净化结合液相色谱-串联质谱(LC-MS/MS)检测方法。样品用甲酸-乙腈(10∶90)进行酸化稀释,离心后取上清液经吸附净化剂(1. 2 g MgSO4+0. 25 g C18+0. 4 g PSA+0. 25 g Al-N)富集净化,过滤后采用LC-MS/MS在多反应监测(MRM)模式下测定。7种真菌毒素在各自范围内线性良好,相关系数(r)均不小于0. 999。在最佳条件下,方法的定量下限(LOQ)为0. 25~5. 0μg/kg,7种毒素的相对标准偏差(RSD,n=6)为1. 1%~7. 7%,平均回收率为71. 5%~119%。该方法操作方便、灵敏度高、重现性好,能满足大批量食品中上述7种真菌毒素残留的检测要求。     

复合免疫亲和柱净化-液相色谱-串联质谱法测定动物源食品中6种黄曲霉毒素和6种玉米赤霉醇类真菌毒素残留量

建立了动物源食品(猪肉、鱼肉、猪肝)中6种黄曲霉毒素(AFB1、AFB2、AFG1、AFG2、AFM1和 AFM2)和6种玉米赤霉醇类真菌毒素(α-玉米赤霉醇、β-玉米赤霉醇、α-玉米赤霉烯醇、β-玉米赤霉烯醇、玉米赤霉酮和玉米赤霉烯酮)残留量的复合免疫亲和柱净化-高效液相色谱-串联质谱(HPLC-MS/ MS)检测方法。样品经β-葡萄糖苷酸/硫酸酯复合酶酶解后,用甲醇-乙腈(20∶80, V/ V)提取,提取液经玻璃纤维滤纸过滤,滤液用PBS 溶液稀释,复合免疫亲和柱富集和净化后,采用 HPLC-MS/ MS 法分析。12种目标分析物中 AFB2和 AFG2的线性范围为0.03~6.0μg/ L,其余目标分析物的线性范围为0.05~20μg/ L,线性相关系数均大于0.999,检出限在0.01~0.03μg/ kg 范围内,定量限在0.04~0.09μg/ kg 范围内。分别以0.5,1.0和5.0μg/ kg 添加浓度水平进行方法学验证,平均回收率为73.6%~98.4%,相对标准偏差(RSD)为1.9%~11.2%。本方法简便、灵敏,能够满足动物源食品中痕量黄曲霉毒素和玉米赤霉醇类真菌毒素残留的测定要求。     

农产品与饲料中T-2毒素免疫亲和柱净化-液相色谱串联质谱检测技术研究

利用T-2毒素单克隆抗体2G7和CNBr活化的Sepharose 4B研制出T-2免疫亲和柱,考察了T-2免疫亲和柱的最佳应用条件。利用免疫亲和柱,建立了农产品与饲料中T-2毒素免疫亲和柱净化/液相色谱-串联质谱(IAC/LC-MS/MS)确证性检测技术,并考察该方法的准确度和精密度。结果表明,T-2毒素在0.5~500.0 ng/g范围内线性关系良好,相关系数为0.999 7,检出限为0.05 ng/g,定量下限为0.17 ng/g。大米、玉米、饲料样品在T-2毒素10,50,100 ng/g的加标水平下,回收率为92.9%~109.7%,相对标准偏差为2.1%~8.3%。对市售36份农产品与饲料样品进行测定,检测结果的相对标准偏差均小于10.0%。     

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%.     

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.     

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.