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。     

液相色谱/串联质谱线性组合法测定动物组织中硝基呋喃代谢产物

研究了对动物组织中4种硝基呋喃类代谢产物AMOZ、AHD、SEM、AOZ的同位素稀释HPLC—MS／MS线性组合分析方法,以2-基苯甲醛作为衍生化试剂,AMOZ—d5、AOZ-4作内标,用乙酸乙脂提取,用自制的净化试剂净化,以乙腈-0．1％甲酸为流动相,采用梯度洗脱,可适应不同种类的动物组织样品前处理,15min可将4种代谢产物完全分离并测定。提出了HPLC—MS／MS多重反应监测线性组合法的原理并进行了验证,回收率为85％-118％;定量限（LOQ）为0．1μg／kg;检出限（LOD）为0．03μg／kg。     

高效液相色谱-串联质谱联用测定富含淀粉食品中丙烯酰胺

以甲基丙烯酰胺作为内标物,用高效液相色谱/串联质谱(HPLC/MS/MS)法测定食品中的丙烯酰胺.均质后的食品样品,加入正己烷经液-液分配去除脂肪,用蒸馏水提取丙烯酰胺,Carrez试剂净化提取样品,净化液经离心后过0.45 μm微孔滤膜,采用HPLC/MS/MS电喷雾电离(ESI),阳离子,多反应监测(MRM)模式检测,外标法定量.方法的线性范围为2～500 μg/L,线性相关系数为0.9997,检出限为2 μg/kg;高中低3个水平的加标回收率分别为99.4%、99.6%和98.4%;相对标准偏差(RSD)均小于7.8%.     

同位素稀释气相色谱串联质谱法测定海产品中的苯并（α）芘的残留量

采用同位素稀释法结合固相萃取净化,建立了海产品中苯并（α）芘残留的气相色谱串联质谱（6C—MS／MS）检测方法。样品经乙腈一丙酮（体积比6：4）溶液提取,硅胶固相萃取净化,苯并（μ）芘用GC—MS／MS测定,同位素D12-苯并芘内标法定量。方法的平均回收率为93％-98％,相对标准偏差为6.2％～12．2％（n=6）,定量限为0．2μg／kg。用该方法测定FAPAS烟熏鱼有证标准样品,测定值与标准值一致。     

大豆中6种磺酰脲类除草剂残留量的高效液相色谱-质谱法测定

建立了LC—MS选择离子监测(SIM)同时检测大豆中6种磺酰脲类除草剂残留量的方法。样品经乙腈提取，正己烷液-液分配，Florisil柱净化，然后采用HPIE—ESI( )-MS测定。6种磺酰脲类除草剂在25～1000μg／L范围内线性良好，相关系数为0．9996～0．99977在0．02～1．0mg／kg范围内，平均加标回收率在72％～99％之间，相对标准偏差为0．9％～7．7％。方法的检出限低于10μg／kg。     

多功能柱净化-高效液相色谱法同时检测小麦中雪腐镰刀菌烯醇和脱氧雪腐镰刀菌烯醇

建立了小麦中雪腐镰刀菌烯醇（NIV）和脱氧雪腐镰刀菌烯醇（DON）的高效液相色谱同时检测方法。样品采用乙腈-水（体积比85：15）混合溶剂进行提取．通过多功能净化柱（MFC）进行一次性净化，以C18柱为分离柱，水-乙腈-甲醇（体积比90：5：5）混合溶剂为流动相进行高效液相色谱分离和检测。在小麦样品中，本方法在0．2～5μg／g添加范围内的凹收率为87％～99％；相对标准偏差为1．5％～8．3％；DON和NIV的检出限分别为0．12和0、16μg／g（5／N=3）。     

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0．10μg/kg。在添加浓度0．5～5．0μg/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0．002～0．50mg／L范围内呈良好的线性关系，线性回归系数大于0．999。     

HPLC-APCl（＋）MS／MS分析动物源性食品中的硝基咪唑类药物残留量

运用高效液相色谱-大气压电离串联四极杆质谱（HPLC-APCI（＋）MS／MS）内标法分析动物源性食品中多种硝基咪唑类（nitroimidazoles）药物——甲硝唑（MNZ）、地美硝唑（DMZ）、替硝唑（TNZ）、洛硝唑（RNZ）的含量。样品添加氘代标示物HMMNI—D^3、IPZ—OH—D^3后，用乙腈提取，通过OASIS HLB C18 SPE柱净化，Waters Sunfire C18色谱柱分离，采用梯度洗脱，流动相为0．1％甲酸水溶液和0．1％甲酸乙腈溶液；大气压电离源正离子MRM模式检测：MNZ m／z 172．0／82．1，172．0／128．0；DMZ m／z 142．0／81．1，142．0／96．1；TNZ m／z 248．0／121．0，248．0／93．1；RNZ m／z 201．0／140．0，201．0／110．0；IPZ—OH—D^3m／z189．0／125．0，189．0／171．0；HMMNI—D^3m／z161．0／58．0，161．0／143．1。方法定量下限（LOQ，S／N〉10）0．2μg／kg，在质量浓度0．2—25．0μg/L范围内，峰面积与质量浓度成良好线性（r〉0．9991）。     

液相色谱-串联质谱法对动物源性食品中14种苯二氮革类药物及其代谢物残留量的同时检测

建立了液相色谱-串联质谱（LC—MS／MS）同时检测动物源性食品中14种苯二氮革类药物及其代谢物残留量的测定方法。在pH5．2乙酸铵缓冲溶液中药物残留经酶解后,用氨水调节pH值大于9．5。溶液经乙酸乙酯-异丙醇（体积比5：1）提取和阳离子交换柱（MCX）净化,并用多反应监测技术所确定的定性离子对检测物进行定性和同位素内标法定量。方法的定量下限为1．0μg／kg,线性范围为1．0～20．0μg/L,各基质的加标平均回收率为64％～117％,相对标准偏差为3．6％～12．3％。     

高效液相色谱/串联质谱法同时测定虾中氯霉素、甲砜霉素和氟甲砜霉素残留量

用高效液相色谱／串联质谱(LC／MS,／MS)同时测定虾中的氯霉素(CAP)、甲砜霉素(TAP)和氟甲砜霉素(FF)。均质后的虾样品,采用碱化乙酸乙酯提取。浓缩提取物经液．液分配(LLP)去除脂肪,C18固相萃取(SPE)柱净化后,采用LC／MS／MS电喷雾电离(ESI),负离子,多反应监测(MRM)模式检测,外标法定量。检出限为：氯霉素和氟甲砜霉素0．01ng/g;甲砜霉素为0．05ng／g。在添加浓度0．1～2．0ng/g范围内,氯霉素回收率为73．9％～96．0％;甲砜霉素回收率为78．6％～99．5％;氟甲砜霉素回收率为74．9％～103．7％;相对标准偏差(RSD)均小于6．4％。     

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.     

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.     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

Synthesis of pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.