固相萃取-HPLC法测定蜂蜜中残留的10种磺胺类药物

研究了用固相萃取-高效液相色谱法同时测定蜂蜜中10种磺胺类药物残留量的方法。样品经三氯甲烷溶液提取,过Oasis HLB C18固相萃取柱净化,用乙腈洗脱10种磺胺,反相高效液相色谱-紫外检测器测定。检测波长为270nm,柱温45℃．流动相：磷酸水溶液-乙腈梯度洗脱．该方法前处理简单,梯度洗脱分离效果和重现性好,在0．010～1．0mg／kg添加水平,10种组分的回收率在86．5％～100．8％之间,室内相对标准偏差在3．5％～8．1％之间,线性范围为0．010～10μg／mL,检出限为0．005mg／kg。该方法快速、灵敏、专属,可用于食品中磺胺类药物残留量的常规检测。     

柱后衍生高效液相色谱法测定猪肉中的链霉素残留

猪肉样品经酸性氧化铝基质固相分散提取和C18固相萃取柱净化,链霉素残留液用甲醇从C18柱上洗脱,在氮吹仪上吹干,残渣用0.01 mol/L庚烷磺酸钠溶液溶解,用柱后衍生高效液相色谱法荧光检测,激发波长和发射波长分别为263、435 nm。该方法线性范围为10~200μg/kg,三个添加水平的回收率为77.4%~86.5%,测量结果的相对标准偏差为2.00%~3.53%(n=5),检出限为5μg/kg。     

液相色谱法测定环氧氯丙烷工业中间体中的己二酸

建立了液相色谱仪测定环氧氯丙烷工业中间体中己二酸含量的方法。样品采用甲醇-10mm01／L磷酸缓冲液（体积比5：95）溶液提取,C18固相萃取柱净化,紫外检测器检测,外标法定量。己二酸在100～2000mg／L范围内线性良好,相关系数大于0．9999,按10s／Ⅳ计算,己二酸定量限为25．0mg／kg。添加回收率为91．1％～112．2％．测定结果的相对标准偏差为4．7％～7．9％（n=5）。该方法简单快速,回收率高,重现性好,满足工业分析要求。     

固相萃取高效液相色谱法测定乳粉中苯并咪唑类药物残留

研究了乳粉中丙硫咪唑、噻苯咪唑、苯硫咪唑、噻苯咪唑酯、苯亚砜苯咪唑等五种苯并咪唑类药物液相色谱测定方法。乳粉中苯并咪唑类药物残留经碱性乙酸乙酯提取,Waters Oasis HLB固相萃取柱净化,以Cloversil C18柱为固定相,甲醇和0．02mol／LKH2P04为流动相,紫外检测器下测定。该法检出限为0．020mg／kg,添加标准0．10mg／kg的回收率为71％-90％。     

柱切换直接进样高效液相色谱法测定蜂蜜中3种抗生素的残留量

建立了柱切换反相高效液相色谱法直接进样分离、测定蜂蜜中3种四环素族抗生素(土霉素OTC、四环素TC、金霉素CTC)残留量的分析方法。方法包括：用缓冲溶液溶解样品、直接进样、二次蒸馏水作流动相在C18预柱上在线富集和净化，然后用柱切换阀将预柱与一个C18分析柱接通，草酸溶液-乙腈-甲醇作流动相、紫外检测器在350nm处检测。各组分回收率均大于85％；相对标准偏差小于10％；标准曲线的相关系数在0．9983～0．9991之间；最低检出浓度(≤0．02mg／kg)，满足欧盟和日本等国要求(0．05mg／kg)。     

高效液相色谱-荧光光度检测尿液中溴鼠灵

提出了高效液相色等荧光光度检测尿液中溴鼠录。尿液经磷酸酸化至pH2．0并在LC-18固相萃取小柱上富集、净化,分取10．0μL试样溶液进行高效液相色谱测定。用XDB C18柱（150mm×2．1mm,5μm）为固定相,以甲醇及稀乙酸溶液（2＋998）以88比12的比例混合后作为流动相,在激发波长为270nm,发射波长为376nm的条件下进行荧光光度检测。结果表明：溴鼠灵在0．05～10．0mg·L^-1范围内呈线性关系,方法的回收率在79．8％～97．0％之间,相对标准偏差在4．0％～4．9％之间,测定限为0．07mg·L^-1。     

高效液相色谱法对吗啡、杜冷丁、安定的同步测定

 利用高效液相色谱法同时分析测定了血液中吗啡、杜冷丁、安定的质量浓度。分析柱为C18,流动相为V（甲醇）：V（25mmol／LKH2PO4）＝90：10,检测波长为285nm。样品血液pH8．5～9．4时,用V（氯仿）：V（异丙醇）＝9：1溶液提取,以氮气吹干有机溶剂后用流动相溶解残渣进样分析。线性范围为0．05～50mg／L,最小检出质量浓度为0．05mg／L,日内与日间精密度CV＜6％。     

高效液相色谱同时测定鸡蛋中4种氟喹诺酮类药物残留

建立了固相萃取—反相高效液相色谱同时分析鸡蛋样品中4种氟喹诺酮类药物残留量的方法。对鸡蛋样品的提取及其在C18固相萃取柱上的净化条件进行了研究,采用高效液相色谱分离,荧光检测器检测(λex=280nm,λem=450nm),外标法定量。4种沙星标准曲线的线性回归系数均在0．9999以上,环丙沙星、恩诺沙星、沙拉沙星的线性范围为2．5～500μg／L;达诺沙星为0．5～100μg/L。鸡蛋样品中4种沙星的加标回收率为78．1％～95．7％;相对标准偏差为4．1％～16．2％。环丙沙星、恩诺沙星、沙拉沙星的最低检出限为10μg／kg;达诺沙星的最低检出限为2μg/kg。     

固相萃取/高效液相色谱法对饲料中阿散酸、硝苯砷酸和洛克沙砷的同时测定

采用强阴离子固相萃取柱净化样品,建立了固相萃耳更／高效液相色谱法同时测定饲料中的阿散酸、硝苯砷酸和洛克沙砷的分析方法。研究了固相萃取吸附条件、洗脱条件,并对提取剂进行了优化。阿散酸、硝苯砷酸和洛克沙砷的定量线性范围为0．5～50mg／L,线性相关系数均大于0．999;检出限阿散酸为0．095mg／kg、硝苯砷酸为0．18mg／kg、洛克沙砷为0．19mg／kg;保留时间的相对标准偏差（RSD）不大于0．51％。样品中3个添加水平的平均回收率为阿散酸80％～83％,RSD为1．0％～3．8％;硝苯砷酸76％～81％,RSD为1．2％～4．6％;洛克沙砷74％～84％,RSD为1．4％-5．5％。     

高效液相色谱法测定火腿肠中的诱惑红

火腿肠经脱脂后，用乙醇-氨-水溶液提取色素，溶液经浓缩后，在酸性条件下用聚酰胺吸附，在碱性条件下解吸附，定容制成水溶液。以C18柱分离，用二极管阵列检测器检测，采用反相高效液相色谱法测定火腿肠中的食用合成色素诱惑红，回收率为85、8％～93．7％，测定结果的相对标准偏差为1．25％～2．39％，线性范围为1～100mg／L，检出限为0．5mg／kg。     

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.     

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.     

Copper-catalyzed multicomponent reactions of 2-iodoanilines,benzylamines, and elemental sulfur toward 2-arylbenzothiazoles

A relatively cheap copper salt-catalyzed, three-component approach providing 2-arylbenzothiazoles in good to excellent yields from readily available 2-iodoanilines, benzylamines, and sulfur powder is reported. This methodology allows preparation of various classes of 2-arylbenzothiazoles and provides a general, reliable approach.