高效液相色谱-串联质谱法同时测定茶叶中290种农药残留组分

建立了茶叶中290种农药的多残留分析方法。前处理采用改进的QuEChERS方法,样品经乙腈提取,氯化钠和无水硫酸镁盐析后,经N-丙基乙二胺(PSA)、石墨化炭黑和无水硫酸镁混合型固相分散净化,提取液过滤膜后经Thermo Accucore aQ色谱柱(100 mm×2.1 mm,2.6μm)进行高效液相色谱分离,以电喷雾电离串联质谱多反应监测模式(MRM)进行检测,外标法定量。结果表明:290种农药在1.0～200μg.L-1范围内具有较好的线性关系,相关系数均大于0.99。3个添加水平(MRL、2MRL、4MRL)下,290种农药的加标回收率为67%～119%;定量下限(LOQ,S/N≥10)均小于10.0μg.kg-1,低于各国规定的限量要求。该方法样品前处理简单、分析时间短、灵敏、可靠,适用于茶叶中多种农药残留的检测。     

凝胶渗透色谱净化-气相色谱-质谱法同时测定金银花中33种农药残留组分

建立了凝胶渗透色谱(GPC)净化、气相色谱-质谱(GC-MS)同时测定金银花中33种有机氯、有机磷和拟除虫菊酯农药残留的方法.样品中的待测农药组分经乙酸乙酯-环己烷混合溶剂(1∶ 1, V/V)提取、GPC净化去除色素等杂质,GC-MS采用全扫描/选择离子监测模式(Scan/SIM)采集数据后进行定性/定量分析.方法的相对标准偏差(RSD)≤16.70 %(6.9～84.6 ng/g,n=5);5种不同加标浓度下,待测农药的标准加入回收率在57.4%(甲胺磷)～109.9%(马拉硫磷)之间;各农药组分的定性检出限(3σ)为0.10～10.5 ng/g,定量检出限(10 σ)为0.33～20.0 ng/g.     

气相色谱-串联质谱法测定烟草中97种农药残留量

利用气相色谱-串联质谱法(GC-MS/MS)检测烟草中97种农药残留。样品以乙腈为溶剂经加速溶剂萃取(ASE),提取液用Carbon-NH2固相萃取小柱净化后,采用VF-5MS色谱柱分离,用电子轰击离子源-多反应监测模式(EI-MRM)检测。97种农药的质量浓度在20~1 000μg·L-1范围内与其峰面积呈线性关系,方法的测定下限(10S/N)在0.02~22.4μg·kg-1之间;在50,100,500μg·kg-1的加标水平下,测得回收率在67.4%~116%之间,测定值的相对标准偏差(n=6)在1.9%~14%之间。     

在线凝胶渗透色谱/气相色谱-质谱联用法测定水果中11种苯氧羧酸类农药

建立了水果中11种苯氧羧酸类农药多残留的在线凝胶渗透色谱/气相色谱-质谱(GPC/GC-MS)分析方法。样品经丙酮-正己烷溶液超声提取,提取液浓缩、干燥后用正丁醇-硫酸溶液衍生,再用Florisil固相萃取柱和在线GPC净化,GC-MS选择离子监测模式(SIM)进行检测和确证。结果显示,11种苯氧羧酸类农药在0.01～1.0 mg/L范围内线性关系良好,相关系数为0.998 7～0.999 9;在0.02～0.10 mg/kg加标范围内,回收率为66%～112%,相对标准偏差为3.4%～11.5%,11种苯氧羧酸类农药的定量下限为7～10μg/kg。该方法简便、快速、灵敏、净化效果好,可满足国际上对水果中多种苯氧羧酸类农药残留分析的要求。     

QuEChERS-凝胶渗透色谱/气相色谱-质谱法同时测定降尘中18种有机氯农药

建立了在线凝胶渗透色谱/气相色谱-质谱(GPC/GC-MS)测定大气降尘中18种有机氯农药残留的分析方法。样品经过简化QuEChERS方法处理后,经乙腈萃取,石墨化炭黑(GCB)净化,一步离心后过膜上机检测。采用该方法能在30 min内处理8~10个样品,配合GPC净化,不仅缩短了分析时间,而且提高了工作效率和结果的准确性。检测结果表明,18种有机氯农药在0.025~2.0 mg/L质量浓度范围内线性关系良好,相关系数为0.991 9~0.999 6,样品检出限为3.2~14.6μg/kg,定量下限为10.7~48.7μg/kg。在0.2、1.0 mg/kg 2个加标水平下,18种有机氯农药的平均回收率为78.6%~117.3%,相对标准偏差(RSD,n=5)为1.3%~5.1%。     

气相色谱-质谱法检测中药材中81种农药残留

建立气相色谱-质谱(GC-MS)法测定中药材中81种农药残留的分析方法。样品用含0.1%乙酸的乙腈提取后用GPC或GPC-SPE固相萃取净化,在选择离子监测模式(SIM)下对天麻、杜仲、金银花、山茱萸进行测定。方法在0.01～1.0μg/mL范围内具有良好的线性关系,相关系数均大于0.999,检出限为6.0～31.9μg/kg,加标回收率为60.8%～128.9%,测定结果的相对标准偏差为7.6%～18.9%(n=6)。该方法操作简便,灵敏度、准确度和精密度均符合农药多残留检测技术要求,适用于中药材中81种农药多残留的测定。     

液相色谱-串联质谱法测定果蔬中喹啉铜的残留量

通过优化液-液萃取(LLE)作为前处理手段,依托液相色谱-串联质谱仪器,建立了适用于蔬菜、水果中喹啉铜残留量的检测方法。样品以1%乙酸在超声条件下提取,提取液经PSA和C18净化后,以液相色谱-串联质谱法测定。本方法在0.01～2.0 mg/L范围内,不同基质中线性关系良好(R~20.99),进行了定量限(LOQ)、0.5倍最大允许残留限量(MRL)、1倍MRL和2倍MRL共4个水平的添加回收实验,回收率均介于82.7%～99.7%之间,相对标准偏差(RSD)在1.73%～11.8%之间,LOQ为0.1 mg/kg。本方法稳定、简便、灵敏,能够满足农药残留检测需求。     

高效液相色谱-串联质谱法测定牛羊组织中苯酚类和水杨酸苯胺类抗蠕虫药多残留

建立了高效液相色谱-串联质谱法同时测定牛、羊组织中硝碘酚腈、氯羟柳胺、氯氰碘柳胺、碘醚柳胺4种苯酚类和水杨酸苯胺类抗蠕虫药的多残留检测方法。样品用乙腈-丙酮(60∶40,V/V)(肌肉、肝脏和肾脏组织)或1%三乙胺乙腈(脂肪组织)超声提取,MAX阴离子固相萃取柱净化,液相色谱分离,采用多反应监测负离子模式对4种药物同时进行定性定量分析,在1~100μg/L范围内,4种药物与其对应峰面积的线性关系良好,相关系数均大于0.99。在牛、羊组织中的检出限(LOD)均为1μg/kg,定量限(LOQ)均为2.5μg/kg。在LOQ、0.5倍高残留限量(MRL)、MRL、2倍MRL添加水平下,4种药物的平均回收率在71%~112%之间,日内相对标准偏差(RSD)在1.1%~14.0%之间,日间RSD在6.4%~14.7%之间。采用本方法对市场上动物可食性组织进行抽样检测,共抽检40份样品,2份样品检测出苯酚类和水杨酸苯胺类抗蠕虫药残留。     

气相色谱-质谱法测定水产品中硫丹和毒死蜱的残留量

提出了气相色谱四极杆质谱法测定鳗鱼中硫丹和毒死蜱农药残留量的方法.样品以乙酸乙酯为提取剂,经浓缩、净化、氮气吹干后用正己烷溶解,采用气相色谱-质谱负化学电离源方式进行选择离子扫描测定.各标准曲线线性范围为0.2～10.0μg·kg-1,回收率为81%～95%;测定结果的相对标准偏差(n=8)小于5%,检出限(3S/N)为0.5μg·kg-1.     

优化的QuEChERS/超高液相色谱-串联质谱法测定鲜茶叶中21种氨基甲酸酯类农药残留

本文应用改进的QuEChERS法结合超高效液相色谱-电喷雾电离串联质谱仪,建立了同时检测鲜茶叶中21种氨基甲酸酯类农药残留的测定方法。样品用1%甲酸乙腈提取,经N-丙基乙二胺(PSA)、C18和石墨化碳黑(GCB)3种复合吸附剂净化,采用UHPLC-MS/MS在动态多重反应监测(DMRM)模式下检测,基质匹配外标法定量。结果表明:21种氨基甲酸酯在2~100μg·L-1范围内线性关系均大于0.995,在三个添加水平下(5、10、25μg·kg-1)的回收率为73.6%~105.0%,相对标准偏差(RSD)为1.4%~7.3%,检出限(LOD)为0.018~0.86μg·kg-1,定量限(LOQ)为0.060~2.87μg·kg-1。该方法样品前处理简单快速、分析时间短、准确度和精密度均符合农药多残留检测技术的要求,适用于鲜茶叶中21种氨基甲酸酯类农药的快速筛查和测定。     

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.