超高效液相色谱-串联质谱法测定畜产品中6种青霉素类药物残留

采用超高效液相色谱-串联质谱法快速测定牛肉和牛奶中青霉素类药物残留。样品以磷酸盐缓冲溶液提取、乙酸锌沉淀蛋白、正己烷脱脂,然后经HLB固相萃取柱净化后,采用超高效液相色谱-串联质谱分离检测,外标法定量。6种青霉素的线性范围均在25.0μg·L-1以内,检出限(3S/N)为2μg·kg-1,测定下限(10S/N)为5μg·kg-1。加标回收率在77.0%~99.8%之间,测定值的相对标准偏差(n=6)在3.7%~13%之间。     

分散固相萃取/超高效液相色谱-串联质谱法测定玉米和土壤中噻酮磺隆-异噁唑草酮及其代谢物残留

建立了分散固相萃取结合超高效液相色谱-串联质谱快速检测玉米和土壤中噻酮磺隆、异噁唑草酮及其代谢物RPA203328与RPA202248残留的分析方法。样品经1%甲酸-乙腈溶剂提取,氯化钠盐析后,提取液经分散固相萃取净化,超高效液相色谱-串联质谱仪检测。考察了提取溶剂及吸附剂种类对分析结果的影响,优化了液相色谱-质谱条件,评估了优化实验条件下的方法性能。结果表明:在玉米样品中,4种分析物的基质效应均大于10%;在土壤样品中,除RPA202248基质效应小于10%外,其余3种分析物的基质效应均大于10%。噻酮磺隆、异噁唑草酮及其代谢物在0.001~1.0μg/m L范围内线性关系良好,相关系数为0.994 5~0.999 5。加标浓度在0.005~0.1 mg/kg范围内的回收率为72.9%~116.5%,相对标准偏差(n=5)为0.75%~17.8%,定量下限为0.005~0.01 mg/kg。该方法前处理简单,分析时间短,准确度和灵敏度高,适用于玉米和土壤中噻酮磺隆、异噁唑草酮及其代谢物残留的快速检测。     

QuEChERS结合HPLC-MC法同时测定黄秋葵中72种农药残留

建立了黄秋葵中72种农药的多残留的液相色谱-串联质谱分析方法。前处理采用改良QuEChERS方法,经乙腈提取,引入缓冲盐体系,使用喷射流离子聚焦-电子喷雾离子源(AJS ESI)和动态多重反应监测(DMRM)模式测定,基质匹配标准曲线定量。结果表明:72种农药在10~200μg·L~(-1)(50~400μg·L~(-1))范围内具有较好的线性关系,相关系数均大于0.997。3个添加水平(10(50)、100、200μg·L~(-1))下,72种农药的加标回收率为78.2%~118.5%。检出限为0.0026~4.9238μg·kg-1,定量限为0.0256~49.2384μg·kg-1,相对标准偏差范围为1.2%~9.8%。该方法样品前处理简单、分析时间短、灵敏、可靠、适用于黄秋葵中多种农药残留的检测。     

ASE-SPE/GC-MS/MS同时测定海洋沉积物中71种农药残留

建立了快速溶剂萃取(ASE)-固相萃取(SPE)/气相色谱-三重四极杆串联质谱同时测定海洋沉积物中71种农药残留的方法。结果表明,ASE的最佳萃取条件为:温度100℃,静态时间5 min,循环1次。在此条件下,样品经正己烷-丙酮(1∶1)萃取,石墨化碳柱净化,多离子反应监测(MRM)模式测定,各种农药在1.0~500.0μg·L-1范围内线性关系良好(r2>0.99),方法的检出限(LOD,3σ)为0.29~108.43μg·kg-1。空白样品在100μg·kg-1加标水平下的回收率为51.3%~104.6%,相对标准偏差(n=6)为0.1%~13.5%。应用建立的方法,对实际样品进行分析,共检测出31种农药。     

分散固相萃取-液相色谱-串联质谱法测定谷物、蔬菜、水果中27种新型杀菌剂

建立了同时检测谷物、蔬菜和水果中27种新型杀菌剂的分散固相萃取-液相色谱-串联质谱(DSPE-LC-MS/MS)分析方法。样品经1%(体积分数)乙酸丙酮溶液提取,以无水硫酸镁(MgSO_4)脱水,经N-丙基乙二胺(PSA)、C_(18)、无水MgSO_4、多壁碳纳米管(MWCNT)混合净化剂净化,经C_(18)色谱柱分离,用乙腈和体积分数为0.1%的甲酸水溶液(含5 mmol/L乙酸铵)梯度洗脱,多反应监测(MRM)正离子模式扫描,采用外标法定量。噻呋酰胺和氯啶菌酯在20.47~200μg/kg范围内线性关系良好,其他25种新型杀菌剂在0.02~100μg/kg范围内线性关系良好,相关系数R~2≥0.995 0,加标回收率为70.02%~117.6%,相对标准偏差(RSD)为0.01%~19.62%(n=3)。噻呋酰胺和氯啶菌酯的检出限为6.15~16.67μg/kg,定量限为20.47~55.5μg/kg。其他25种新型杀菌剂的检出限为0.006~4.44μg/kg,定量限为0.02~14.79μg/kg。该方法简便、快速、可靠,可用于谷物、蔬菜、水果中27种新型杀菌剂的快速测定。     

高效液相色谱-串联质谱法测定农产品中矮壮素残留量

提出了农产品中矮壮素的高效液相色谱-串联质谱(HPLC-MS/MS)分析方法。样品经甲醇-水(1+1)溶液提取,正己烷液液萃取后,采用阳离子交换固相萃取柱净化。所得净化液以阳离子交换树脂与C18混合填料色谱柱为固定相,以含0.1%(体积分数)乙酸的乙腈-10mmol·L-1乙酸铵(1+1)溶液为流动相进行等度洗脱,采用电喷雾正离子源,多反应监测模式检测,同位素内标法定量。矮壮素的线性范围为1.0~100μg·L-1,检出限(3S/N)为5μg·kg-1,测定下限(10S/N)为10μg·kg-1。矮壮素在10,100,500μg·kg-1等3个加标水平的回收率为90.5%~98.5%之间,测定值的相对标准偏差(n=6)在0.99%~2.2%之间。     

HPLC-MS/MS测定氯羟吡啶在牛奶中的残留

建立了牛奶中氯羟吡啶残留检测的高效液相色谱-串联质谱方法(HPLC-MS/MS)。样品经乙腈提取,碱性氧化铝固相萃取柱(Alumina-B)净化,以乙腈+0.1%甲酸水溶液作为流动相洗脱,采用电喷雾离子源(ESI),多反应监测(MRM)方式进行采集,外标法定量。结果表明,氯羟吡啶在1~200ng·m L-1浓度范围内呈现良好的线性关系,相关系数R2大于0.99,方法检测限为0.2μg·kg-1,从5、10和50μg·kg-13个水平添加浓度检测结果可以看出,方法回收率在93.4%~102.6%,相对标准偏差不大于6.5%。     

固相萃取-超高效液相色谱-串联质谱法同时测定果蔬中6种酰胺类农药残留量

建立了同时测定果蔬中6种酰胺类农药的固相萃取-超高效液相色谱-串联质谱(SPE-UPLC-MS/MS)方法。样品经乙腈高速匀浆提取、Florisil固相萃取柱净化,采用超高效液相色谱-串联质谱法测定6种农药。质谱分析采用电喷雾电离,正负双离子扫描,多反应监测(MRM)模式。结果表明:6种农药在0.0005~1.00 mg/L范围内均呈现良好的线性关系,相关系数均大于0.999;在0.01、0.1和1.0 mg/kg(氟苯虫酰胺为0.001、0.01和0.1 mg/kg) 3个浓度添加水平下的平均回收率为72.4%~119.4%,相对标准偏差(n=5)小于15%;定量限为0.01 mg/kg(溴氰虫酰胺、双炔酰菌胺、啶酰菌胺、氟吡菌胺和噻呋酰胺)和0.001 mg/kg(氟苯虫酰胺)。该方法简单、快速、重现性好、灵敏度高,可满足果蔬中6种酰胺类农药残留检测的要求。     

盐析辅助均相液液萃取/分散固相萃取-超高效液相色谱串联质谱法测定蜂蜜中新烟碱类农药残留

以盐析辅助均相液液萃取结合分散固相萃取作为前处理方法,建立了超高效液相色谱串联质谱快速检测蜂蜜中吡虫啉、噻虫嗪、噻虫胺、噻虫啉、啶虫脒及氯噻啉6种新烟碱类农药残留的分析方法。样品用乙腈提取,氯化钠盐析分层,提取液经分散固相萃取法净化,采用超高效液相色谱串联质谱检测器进行分析。考察了萃取剂种类、体积及氯化钠质量对萃取效率的影响,评估了在优化实验条件下的基质效应和方法性能。结果表明:除吡虫啉外,其余5种新烟碱类农药的基质效应均大于10%。6种新烟碱类农药在0.2~100μg/L范围内线性关系良好,相关系数(r2)为0.998 1~0.999 7。加标浓度为1.0~50.0μg/kg时,6种新烟碱类农药的加标回收率为77.0%~106%,相对标准偏差为2.4%~19.8%。方法的检出限为0.2~0.4μg/kg,定量下限为1.0μg/kg。该方法前处理简单,分析时间短,准确度和灵敏度高,重现性好,适用于蜂蜜中6种新烟碱类农药微量残留的快速测定。     

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.