高效液相色谱-串联质谱法测定蜂蜡中硝基呋喃类代谢物

建立了高效液相色谱-串联质谱检测蜂蜡中呋喃唑酮代谢物(AOZ)、呋喃它酮代谢物(AMOZ)、呋喃西林代谢物(SEM)、呋喃妥因代谢物(AHD)残留的分析方法。试样采用正己烷预溶解,酸性水溶液中衍生化,经HLB固相萃取小柱净化,用Agilent Eclipse Plus-C18柱(100 mm×2.1 mm,3.5μm)分离,电喷雾离子源正离子(ESI+)、多反应监测(MRM)模式串联质谱进行测定。结果表明,4种硝基呋喃类代谢物在0.5~10 ng/m L范围内均具有较好的线性关系,相关系数大于0.995。在0.5,1.0和2.0μg/kg添加水平下,样品中4种硝基呋喃类代谢物的回收率在71.8%~119.0%之间,相对标准偏差(RSD,n=6)均小于10%,方法定量限(S/N10)为0.5μg/kg。方法适用于日常蜂蜡样品中4种硝基呋喃类代谢物残留的定性、定量分析。     

LC-MS/MS检测蜂胶中硝基呋喃类代谢物的残留

建立了蜂胶中硝基呋喃类代谢物液相色谱-串联质谱检测方法。样品经固相萃取、衍生、乙酸乙酯提取后进行质谱分析。在1.0、2.0、5.0μg/kg 3个添加水平下,硝基呋喃类代谢物的平均回收率为92.6%～99.3%,日内相对标准偏差小于10%,日间相对标准偏差小于15%。在0.5～20 ng/mL范围内呈良好的线性(r>0.99),检测限为0.25μg/kg,定量限为1.0μg/kg。方法适用于蜂胶中硝基呋喃类代谢物的分析确证。     

超声辅助衍生-液相色谱/串联质谱法快速测定养殖水体中硝基呋喃类代谢物的残留量

建立了超声辅助衍生结合液相色谱/串联质谱(UAD-LC-MS/MS)快速测定水产养殖水体中4种硝基呋喃代谢物的方法。实验对比了超声辅助衍生和传统振荡衍生的效果,优化了色谱质谱条件以及衍生时间。水样经超声辅助的方式衍生,以2-硝基苯甲醛为衍生化试剂,再经乙酸乙酯提取,在正离子模式下以电喷雾电离串联质谱进行测定,内标法定量。在优化的实验条件下,4种代谢物在0.5~50 ng/m L范围内线性良好,相关系数0.998,方法检出限为0.02 ng/m L,定量限为0.05 ng/m L。在0.1,0.5和5 ng/m L的添加水平下,4种代谢物的平均回收率处于91.9%~104%之间,相对标准偏差(RSDs)处于2.1%~8.1%之间。测定了12份养殖水体中4种硝基呋喃代谢物的残留量,其中2份样本中检出呋喃西林代谢物氨基脲。方法可以准确测定养殖水体中硝基呋喃代谢物的残留量。     

HPLC–MS/MS法测定南美白对虾苗中硝基呋喃类代谢物残留

研究了南美白对虾苗中4种硝基呋喃代谢物呋喃唑酮代谢物(AOZ)、呋喃它酮代谢物(AMOZ)、呋喃妥因代谢物(AHD)、呋喃西林代谢物(SEM)的高效液相色谱–串联质谱(HPLC–MS/MS)测定方法。以水解衍生并添加4种同位素内标的方法对样品进行处理,补偿了衍生化效率,提高了定量的准确性。实验结果表明,AOZ,AMOZ的检出限为0.10μg/kg,SEM,AHD的检出限为0.25μg/kg;AOZ,AMOZ的定量下限为0.40μg/kg,SEM,AHD的定量下限为0.50μg/kg。方法加标回收率在88.2%~97.6%之间,相对标准偏差在4.6%~8.1%(n=6)之间。该法检测灵敏度高,测量结果的精密度和准确度满足药物残留检测要求。     

海产品中硝基呋喃类原药的超高效液相色谱串联质谱测定

研究了海产品中4种硝基呋喃类原药(呋喃唑酮、呋喃妥因、呋喃西林、呋喃它酮)的固相萃取/超高效液相色谱串联质谱分析方法。样品用甲醇-偏磷酸(4∶6)溶液提取,经HLB柱净化,以甲醇和5 mmol/L乙酸铵溶液为流动相,经ACQUITYTMBEH C18柱分离后,在UPLC-MS/MS多反应监测模式下进行定性定量分析。其中呋喃唑酮和呋喃它酮采用正离子扫描方式,呋喃西林和呋喃妥因采用负离子扫描方式进行质谱分析。呋喃唑酮和呋喃它酮的检出限为0.15μg/kg、定量下限为0.5μg/kg,呋喃西林和呋喃妥因的检出限为0.3μg/kg、定量下限为1.0μg/kg。在0.50~10.0μg/kg添加水平下,4种硝基呋喃原药的平均加标回收率为75%~98%,相对标准偏差均小于11%。     

高效液相色谱-串联质谱联用测定蜂王浆中的四种硝基呋喃类药物的代谢物

报道了高效液相色谱-串联质谱联用测定蜂王浆中呋喃唑酮、呋喃西林、呋喃妥因和呋喃它酮4种硝基呋喃类药物的代谢物残留的方法。以三氯乙酸作为蜂王浆的蛋白质沉淀剂,同时提供衍生化反应所需的酸性环境;使用4种同位素内标,补偿了衍生化效率、衍生后样品溶液的pH值及光照对定量结果所产生的影响,极大地提高了定量的准确性。实验结果表明,呋喃它酮代谢物的检测下限可以达到0.03 μg/kg,其他3种硝基呋喃类药物的代谢物的检测下限可以达到0.05 μg/kg（S/N大于5）;呋喃它酮代谢物的定量下限可以达到0.20 μg/kg,其他3种硝基呋喃类药物的代谢物的定量下限可以达到0.25 μg/kg（S/N大于10）;线性范围为0.4~20 ng/mL,添加回收率为97.7%~104.8%(内标校正),相对标准偏差（RSD）为2.7%~9.7%。     

液液萃取柱-液相色谱-串联质谱法测定乳制品中硝基呋喃类代谢物残留

采用液液萃取柱-超高效液相色谱-串联质谱技术建立了乳制品中硝基呋喃类代谢物的快速测定方法。硝基呋喃类代谢物衍生化反应后,利用EXtrelut NT液液萃取小柱进行净化富集,采用正离子多反应监测模式,内标法定量。硝基呋喃类代谢物在0.10~10.0μg/L范围内线性关系良好,检出限为0.04~0.10μg/kg,回收率范围为71.5%~109.4%,相对标准偏差(RSD)范围4.6%~9.8%。方法适用于乳制品中硝基呋喃类代谢物的快速检测。     

高效液相色谱-串联质谱法快速检测海参中硝基呋喃代谢物前处理方案的探讨

利用高效液相色谱-串联质谱(HPLC-MS/MS)联合改进的QuEChERS建立了同时测定活海参中硝基呋喃类药物的代谢物氨基脲、1-氨基乙内酰脲、3-氨基-2-唑烷基酮、5-甲基吗啉-3-氨基-2-唑烷基酮的方法。样品经盐酸水解,2-硝基苯甲醛衍生,37℃水浴16 h,调节至pH 7.0~7.5,QuEChERS提取净化,氮吹至干后,用20%乙腈水定容,经C18色谱柱分离,以乙腈-0.1%甲酸溶液为流动相进行梯度洗脱,用HPLC-MS/MS以多反应监测模式进行检测。结果表明,该方法的线性范围为1.0~10μg/L,4种代谢物的相关系数均不小于0.999,检出限和定量下限分别为0.15μg/kg和0.5μg/kg,在0.5,1.0,2.0,5.0μg/kg的加标水平下,回收率为88.0%~109.6%,相对标准偏差(RSD)为3.8%~11.0%。用此方法对大连地区200批海参进行检测,合格率为95%。该方法前处理操作简便,省时,溶剂消耗量小,可作为同时分析活海参中4种硝基呋喃类药物代谢物残留量的有效手段。     

高效液相色谱法检测水产品中硝基呋喃类代谢物残留量

建立了水产品中硝基呋喃类代谢物残留量测定的样品处理方法和高效液相色谱分析方法.样品经酸解、2.氯苯甲醛衍生后用乙酸乙酯萃取、SPE柱净化,经高效液相-紫外检测器测定.本方法4种硝基呋喃类代谢物的定量限均为1.0μg/kg,在5.0～500μg/L质量浓度范围内,4种硝基呋喃类代谢物的工作曲线均呈良好线性,在2个添加浓度水平的平均回收率为76%～102%,相对标准偏差均小于10%(n=6).该方法适用于定性定量水产品中硝基呋喃类代谢物的残留分析.     

高效液相色谱-串联质谱法测定香肠中硝基呋喃代谢物

高效液相色谱法与串联质谱联用法应用于香肠中硝基呋喃代谢物的测定.试样在稀盐酸溶液中同时加入一定量的衍生试剂邻硝基苯甲醛后,在37 ℃放置过夜使其中与蛋白质结合的硝基呋喃代谢物水解并衍生化.将此溶液的酸度调节至pH 7.0～7.5后,以3 000 r·min-1的转速离心10 min,分出上层清液,用乙酸乙酯萃取.所得萃取液用作HPLC-MS/MS测定.在电喷雾正离子条件下,用多离子反应监测模式,以外标法对萃取液中对经衍生化后的各硝基呋喃代谢物进行定量.在0.5～10 μg·kg-1范围内进行标准加入回收试验,4种硝基呋喃代谢物的回收率在77.3%～90.7%之间,测定值的相对标准偏差小于9%.测得方法的检出限(S/N=3)为:0.10 μg·kg-1对呋喃唑酮、呋喃它酮及呋喃西林的代谢物和0.20 μg·kg-1对呋喃妥因代谢物.     

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.