固相萃取-气相色谱质谱测定动物组织中氯霉素的残留量

对鸡肉、猪肉、猪肝、鸭肝等动物组织样品中的氯霉素残留的检测方法进行了研究。用乙酸乙酯和磷酸盐缓冲溶液提取动物组织中的氯霉素残留,用硅胶和C18固相萃取柱对乙酸乙酯提取物进行净化和富集。净化后的提取物用BSTFA衍生化和气相色谱-质谱-负化学电离源选择离子定量检测(选择离子为376,378,466,468,470)。通过对提取、净化富集条件的优化,建立了动物组织中氯霉素残留量的检测方法。该方法对不同基体样品的加标回收率为80％～100％之间;相对标准偏差小于20％;方法的检出限为0．1μg／kg。     

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％。     

荧光衍生化法测定牛奶中氯霉素残留的研究

研究氯霉素荧光衍生化反应的实验条件，建立荧光分光光度法测定牛奶中氯霉素残留的新方法。牛奶中的氯霉素，用乙酸乙酯超声提取3次，浓缩，盐水溶解，正己烷脱脂，再经乙酸乙酯反萃取，氮气吹干，经还原，用荧光胺衍生化测定。氯霉素衍生化产物质量浓度在12．5～500ng／mL范围内，相对荧光强度与质量浓度关系为F=1．44 0.1424ρ，r^2=0．9998。加标回收率为81％～87％，相对标准偏差为3．9％～8．4％。本方法牛奶中氯霉素可达2．5ng/mL。     

采用液相色谱-串联质谱同时检测动物源性食品中胺苯醇类药物及其代谢产物

建立了采用液相色谱-串联质谱(LC-MS/MS)同时测定动物源食品中氯霉素、甲砜霉素、氟苯尼考以及氟苯尼考胺残留量的方法。三类胺苯醇类药物及其代谢物用氨化乙酸乙酯(97+3v/v)提取,C18小柱净化;其中氯霉素、甲砜霉素、氟苯尼考用内标法定量,氟苯尼考与氟苯尼考胺用外表法定量。方法的定量测定低限氯霉素为0.1μg/kg,甲氟霉素、氟苯尼考胺为1.00g/kg,各基质的加标平均回收率在73.8%～120.5%之间,相对标准偏差≤25%。     

凝胶渗透色谱净化一气相色谱分离同时测定糙米中50种有机磷农药残留

研究了同时检测糙米中50种有机磷农药残留的方法。用乙酸乙酯提取，凝胶渗透色谱净化，环己烷-二氯甲烷(50：50，V/V)作为流动相，气相色谱-氮磷检测器检测。方法检出限为0．001～0．089mg／kg；相对标准偏差为1．7％～18．9％；40多种农药平均回收率在70％～120％。     

UPLC-MS-MS法快速测定含乳冷冻饮品中氯霉素残留量

建立了UPLC-MS-MS法测定含乳冷冻饮品中氯霉素的含量。样品经高氯酸沉淀蛋白,乙酸乙酯提取,浓缩干燥,流动相溶解,正己烷脱脂后,采用ACQUITYUPLCBHEC18色谱柱分离,以1％甲酸水溶液一乙腈为流动相进行梯度洗脱,利用电喷雾质谱负离子监测模式对氯霉素进行检测。氯霉素浓度在0．1～100．0ng／mL范围内与色谱峰面积呈良好的线性,线性相关系数r=0．9986。加标回收率为81．5％～103．4％,测定结果的相对标准偏差为1．72％-3,18％（n=5）,以3倍信噪比计算方法的检出限为0．1μg／kg。     

高效液相色谱串联质谱测定蜂蜜、蜂王浆中氯霉素残留

前处理方法包括添加同位素内标氯霉素-d5和采用10％偏磷酸沉淀蜂王浆产品中的蛋白质,上清液经乙酸乙酯提取,自制硅胶柱和Oasis小柱净化。净化后的提取溶液用高效液相色谱-电喷雾电离质谱检测,多反应监测3对离子（321．0／256．9、321．0／194．0、321．0／175．8）。该方法对不同基质样品的加标回收率为91％-107％;相对标准偏差小于10％;蜂蜜和蜂王浆的方法检出限分别为0．1μg／kg和0．2μg／kg。     

同位素稀释液相色谱-串联质谱法准确测定猪肉中的氯霉素

建立了同位素稀释质谱测定猪肉中氯霉素残留的方法,对影响溶剂提取、萃取净化、液相色谱-质谱检测方法准确度的因素进行了量化与优化。猪肉样品经液氮冷冻粉碎,加入氯霉素-D5同位素内标和0.1 mol/L醋酸钠缓冲溶液(pH 5),用乙酸乙酯提取4次,正己烷脱脂,HLB固相萃取小柱净化后采用负离子多反应监测模式下的液相色谱-质谱技术检测。方法的线性范围为0.01～0.5 ng/g,相关系数r2大于0.999;检出限和定量限分别为0.004 ng/g和0.02 ng/g;在0.02 ng/g和1.0 ng/g加标水平的回收率(n=3)分别为95.2%～109.1%和99.7%～102.5%;日内和日间相对标准偏差均小于2%。研究了氯霉素及氯霉素-D5的基体效应,测得不同流动相和稀释溶剂组成时基体效应因子k的范围在0.950～1.015之间。研究结果对同位素稀释质谱痕量残留检测结果准确度的控制、方法的建立与验证具有参考意义。     

高效液相色谱串联质谱法同时测定饲料中氯霉素、甲砜霉素与氟甲砜霉素残留

以D5-氯霉素为内标,建立了高效液相色谱-电喷雾串联质谱测定饲料预混料、配合饲料中氯霉素、甲砜霉素与氟甲砜霉素含量的方法.样品磨碎后,采用乙酸乙酯提取,离心后上清液于45℃下氮气吹干,溶解残渣并用正己烷液液萃取净化处理,经C18固相萃取净化后,通过Agilent Eclipse C18(150 mm ×4.6 mm,5μ nn)色谱柱以甲醇-0.1％甲酸作流动相梯度洗脱分离,采用电喷雾电离(ESI)、多反应监测(MRM)负离子扫描方式进行定性与定量分析.方法的检出限(LOD)为0.5μg/L,定量下限(LOQ)为1.0 μg/L,待测物与内标物定量离子的峰面积比值与待测物的质量浓度在0.5～10.0 μg/L范围内呈良好线性关系,相关系数(r2)不低于0.9990.在0.5～2.0 μg/kg范围内,3个水平的加标回收率为78％～107％,相对标准偏差(RSDs,n=6)均小于10％.     

超高效液相色谱-串联四极杆质谱法测定水产品中氯霉素残留量

建立超高效液相色谱-串联四极杆质谱法测定水产品中氯霉素残留量的方法。样品均质后经乙酸乙酯提取,正己烷脱脂(或用固相萃取柱净化),超高效液相色谱分离,串联四级杆质谱检测,同位素内标法定量。方法在0.05～1.0μg/kg的添加范围内的平均回收率为84.9%～103.3%,相对标准偏差为3.2%～5.2%,定量检测限为0.02μg/kg。方法适用于各种水产品基质的氯霉素残留检测。     

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.     

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.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.