基于增强型脂质去除固相小柱净化结合液相色谱-串联质谱法测定猪肉和猪肝中的双甲脒农药及其代谢物

建立了采用增强型脂质去除(EMR-Lipid)固相小柱净化结合液相色谱-串联质谱(LC-MS/MS)测定猪肉和猪肝中双甲脒 (AMZ) 及其3种代谢物2,4-二甲基苯胺(DMA)、单甲脒(DMPF)和2,4-二甲基苯基甲酰胺(DMF)残留量的方法。 样品经乙腈蛋白沉淀及盐析提取,通过Captiva EMR-Lipid 过滤小柱净化,滤膜过滤后,采用Agilent ZORBAX Eclipse Plus C₁₈柱(50 mm×2.1 mm,1.8 μm)分离,以0.1%甲酸水溶液与0.1%甲酸乙腈为流动相进行梯度洗脱,采用电喷雾离子源正离子方式扫描,多反应监测模式进行检测。 结果表明,在猪肝与猪肉中AMZ、DMA线性范围为1～200 μg/kg,DMPF和DMF的线性范围为0.1～200 μg/kg,相关系数(R²)均大于0.991;AMZ、DMA、DMPF和DMF的方法定量限(S/N=10)分别为0.6、0.6、0.05、0.05 μg/kg;对空白猪肉和猪肝进行0.1、1、5、50 μg/kg 4个浓度水平的加标实验,回收率在60.2%～127.4%之间,相对标准偏差均低于12%。 该方法简便、快捷,适用于猪肉和猪肝中双甲脒及其代谢物残留量的同时测定。     

液相色谱-串联质谱法测定蜂蜜中双甲脒及其代谢产物残留量

称取蜂蜜样品2.00g,加入同位素内标40ng,用pH 7的磷酸二氢钾-磷酸氢二钠缓冲溶液溶解并稀释至10.0 mL。充分混匀后,加入乙腈10.0 mL和氯化钠2.0g,离心涡旋提取5min。取上层乙腈相保留待用,于下层水相中再加入乙腈10mL重复提取1次。合并两次提取液,加乙腈定容至20.0mL。分取此提取液1.0mL,加入于己预置N-丙基乙二胺(PSA)25mg、十八烷基硅烷(C_(18))10mg和MgSO_4 30mg的离心管中,充分混匀后,高速离心,进行分散固相萃取(dSPE)净化。转移全部上清液,加水定容至2.0 mL,此溶液供液相色谱-串联质谱法(LC-MS/MS)分析。色谱分离中采用XDB-C_(18)色谱柱为固定相,用不同比例的φ0.15%甲酸溶液(A)和乙腈(B)的混合液作为流动相进行梯度淋洗。所得各洗脱液按工作条件进行MS/MS测定双甲脒及其代谢物单甲脒、2,4-二甲基苯基甲酰胺和2,4-二甲基苯胺的残留量。由于采用空白蜂蜜作基体加入混合标准溶液制作工作曲线,并加入同位素内标参与定量,有效地克服了基质效应。上述4种化合物工作曲线的线性范围为0～100μg·kg~(-1),测定下限(10S/N)依次为0.10,0.20,5.0,2.0μg·kg~(-1)。在实际样品基体中加入3个浓度水平的标准溶液(5.0,10,20μg·kg~(-1))进行回收试验,测得回收率均大于80%,测定值的相对标准偏差(n=6)均小于10%。所提出方法具有简便、快速的优点,其测定下限能满足目前国内外的规定要求。     

固相萃取-气相色谱法检测枸杞子中啶虫脒的残留量

采用固相萃取-气相色谱法检测枸杞子中啶虫脒残留量。用乙腈提取样品中的啶虫脒,活性炭和中性氧化铝串联固相萃取柱净化,用气相色谱微电子捕获检测器进行检测。在0.02~5.0mg/L的浓度范围内,啶虫脒的线性关系良好,相关系数r=0.9999,回收率在81.3%~108.8%之间,检出限为0.005mg/kg。该方法可用于枸杞子中啶虫脒残留量的测定。     

固相萃取-高效液相色谱法测定水果中单甲脒的残留量

建立了固相萃取-高效液相色谱法(SPE-HPLC)测定水果中农药单甲脒残留量的检测方法.用HCl溶液将样品中单甲脒转化为盐酸盐并溶于水中,在碱性条件下用乙腈提取,经碱性氧化铝固相萃取柱净化.采用C18柱(250 mm×4.6 mm,5 μm)分离,以甲醇-0.01 mol/L乙酸铵溶液(50∶ 50, V/V)为流动相,在254 nm下检测.本方法可以将单甲脒与基质良好分离,在0.01～10 mg/L浓度范围内线性良好(R2=0.9999);检出浓度为0.0013 mg/kg,回收率为80.7%～95.3%,相对标准偏差小于7%,可用于水果中单甲脒残留量的检测.     

分散固相萃取结合高效液相色谱-串联质谱快速测定茶叶中的苦参碱

建立了茶叶中苦参碱残留量的分散固相萃取-液相色谱-串联质谱检测方法。样品经氨水碱化，乙腈提取，浓缩后经分散固相萃取净化，以乙腈和乙酸铵溶液为流动相进行梯度洗脱，C18色谱柱分离，采用电喷雾离子源，正离子扫描，多反应监测(MRM)模式测定，外标法定量。结果表明，苦参碱在1.0～20 ng/mL范围内线性关系良好，相关系数大于0.998。方法对于茶叶中苦参碱的定量限为5.0μg/kg。在5.0、10和50μg/kg 3个加标浓度水平下的加标回收率为80%～98%,相对标准偏差均不大于7.2%。本方法快速、简便，准确性和灵敏度较高，可作为茶叶中苦参碱残留量的有效检测方法。     

固相萃取/液相色谱-串联质谱法测定鱼塘水中双甲脒及其代谢产物

建立了鱼塘水中双甲脒及其代谢产物的液相色谱-串联质谱检测方法。采用固相萃取前处理,考察了不同的固相萃取柱和洗脱溶剂对检测结果的影响,优化了固相萃取条件。结果表明,在优化条件下,4种目标物在20~2 000 ng/L范围内线性关系良好(r为0.997 5~0.999 1),该方法对双甲脒及其代谢产物的检出限为0.4~1.0 ng/L。鱼塘水中双甲脒及其代谢产物的回收率为69.7%~91.3%,方法具有良好的灵敏度、重现性、稳定性和专属性,可满足日常的分析要求。     

烟草中啶虫脒残留量的测定

建立了烟草中啶虫脒残留量的气相色谱检测方法.样品采用乙腈提取,经弗罗里硅土层析柱净化,用环己烷-异丙醇(体积比为9∶1)溶液淋洗,用电子捕获检测器进行测定.结果表明,该方法的回收率为82.8%～100.3%,相对标准偏差小于5%(n=5),检出限为0.18 μg/g.该法适合于烟草中啶虫脒残留量的检测.     

高效液相色谱-串联质谱法测定蔬菜水果中双甲脒及其代谢产物

建立了高效液相色谱-串联质谱（HPLC-MS/MS）检测蔬菜水果中双甲脒（AMZ）及其降解或代谢产物单甲脒（DMPF）、2，4-二甲基苯基甲酰胺（DMF）和2，4-二甲基苯胺（DMA）的分析方法。样品经0.1 mol/L NaOH溶液稀释、正己烷-异丙醇（2：1，v/v）混合提取液提取，然后采用HPLC-MS/MS对目标物进行定性确证和定量分析。采用Phenomenex Kinetex C18色谱柱（100 mm×4.6 mm，2.6 μm）分离，以0.1%（v/v）甲酸水溶液和甲醇为流动相进行梯度洗脱，采用电喷雾电离（ESI）源、正离子监测模式进行检测。在1.0~200.0 μg/L范围内，4种目标化合物呈良好的线性关系，相关系数（r）大于0.99；方法的定量限为0.01~0.4 μg/kg。4种目标化合物在0.5、5.0和20.0 μg/kg 3个水平下的加标回收率为62.5%~105.0%，RSD为7.5%~17.6%。该法简便快捷，准确可靠，灵敏度高，定量限满足目前国内外残留限量要求。     

固相萃取-气相色谱检测茶叶中啶虫脒残留量

建立了茶叶中啶虫脒残留量的气相色谱分析方法.样品用乙腈超声提取,经Envi-Forisil固相小柱净化,以V(石油醚):V(丙酮)=1:1洗脱,GC-ECD检测,外标法定量.在0.01～0.10 mg/kg的添加水平,平均回收率在90.9～94.2%之间,相对标准偏差在1.6%～3.4%,该方法的检出限为0.01 mg/kg.该方法的灵敏度、准确度和精密度均符合农药残留测定的技术要求.     

气相色谱-质谱联用法测定紫菜中扑草净的残留量

建立了固相萃取净化与气相色谱-质谱联用技术测定紫菜中扑草净除草剂残留量的检测方法。样品由乙腈溶剂提取浓缩后,活性炭和氨基柱双柱串联固相萃取净化,由气相色谱-质谱联用技术测定。方法定量限为2μg/kg,满足国外最低10μg/kg的限量要求;方法在10,40和100μg/kg 3个添加水平和不同人员操作条件下,回收率均稳定在90%~120%之间,RSD%≤7.1%。     

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.