双柱固相萃取净化-液相色谱-串联质谱法测定牛奶和奶粉中链霉素和双氢链霉素残留量

建立了双柱固相萃取净化-液相色谱-串联质谱(HPLC-MS/MS)测定牛奶和奶粉中链霉素和双氢链霉素残留量的分析方法。样品用H3PO4溶液提取,三氯乙酸沉淀蛋白,苯磺酸型和羧酸型固相萃取柱净化,经Atlantis C18色谱柱分离,以电喷雾离子源在正离子多反应监测(MRM)模式下进行测定。牛奶中链霉素和双氢链霉素的方法检出限均为4μg/kg,定量限均为10μg/kg,奶粉中链霉素和双氢链霉素的方法检出限均为30μg/kg,定量限均为80μg/kg,方法回收率为80%~86%,相对标准偏差为5.9%~11.5%。本方法适用于牛奶和奶粉中链霉素和双氢链霉素残留量的测定。     

鳗鱼、蜂蜜中链霉素、双氢链霉素残留量的液相色谱-串联质谱法测定

建立了液相色谱-串联质谱(HPLC-MS/MS)法同时检测鳗鱼和蜂蜜中链霉素和双氢链霉素残留量的方法。样品用庚烷磺酸钠和磷酸盐缓冲液提取,经SUPELCO LC-C18固相萃取净化后,采用Thermo Aquasil-C18色谱柱(150 mm×4.6 mm,3μm)分离,以含0.3%乙酸的乙腈溶液和0.3%乙酸水溶液为流动相进行梯度洗脱,多反应监测模式测定,外标法定量。该方法在10~100μg/kg质量浓度范围内线性关系良好,定量下限均为10μg/kg。方法的回收率为89.6%~110.3%,相对标准偏差为2.3%~20.9%。该方法简便、实用、准确、快捷,能够满足蜂蜜和鳗鱼中链霉素和双氢链霉素残留量的检测需要。     

串联双柱固相萃取-液相色谱-串联质谱法测定番茄酱中链霉素和双氢链霉素残留量

建立了同时测定番茄酱中链霉素和双氢链霉素残留量的串联双柱净化-液相色谱-串联质谱方法。样品中的残留物用磷酸盐缓冲液(pH 4)提取,经分散固相萃取净化和串联双柱固相萃取净化后,用极性色谱柱在梯度洗脱条件下分离待测物,采用正离子电喷雾离子源(ESI+)在多反应监测(MRM)扫描模式下进行测定,外标法定量。链霉素和双氢链霉素在0.01～0.2 mg/L质量浓度范围内线性关系良好,相关系数(r)大于0.999。链霉素和双氢链霉素的定量限均为0.02 mg/kg,回收率为71%～101%,相对标准偏差为2.3%～15%。该方法操作简便,净化效果好,灵敏,准确,适用于检测和分析番茄酱及其制品中链霉素和双氢链霉素残留量。     

固相萃取/高效液相色谱-串联质谱法测定植物性食品中链霉素与双氢链霉素

建立了植物性食品(苹果、芹菜、甜椒、干扁豆)中链霉素(Streptomycin,STR)和双氢链霉素(Dihydrostreptomycin,DHS)的高效液相色谱-串联质谱(HPLC-MS/MS)检测方法。样品经磷酸盐缓冲溶液提取,借助WCX固相萃取柱富集净化后,采用Atlantis Hilic Silica亲水作用色谱柱(100 mm×3.0 mm,3μm)分离,乙腈-0.1 mol/L甲酸铵和0.1%甲酸溶液等度洗脱,以电喷雾电离串联质谱多反应监测(MRM)正离子模式进行检测,外标法定量。结果显示,链霉素和双氢链霉素在10～120μg/L质量浓度范围内线性良好,相关系数(r)均大于0.999,定量下限均为125μg/kg。本底空白的4种样品基质在3个添加水平(125、250、500μg/kg)下的平均回收率为83.6%～101%,相对标准偏差为2.3%～7.8%。该方法无需使用对LC-MS联用仪造成污染的离子对试剂,且方法操作简便、快速、可靠、稳定,能满足大部分植物性食品中链霉素和双氢链霉素的检测需要。     

液相色谱-串联质谱法测定葡萄中链霉素和双氢链霉素

研究系统地优化了样品前处理过程及仪器分析中影响链霉素和双氢链霉素残留分析准确度与响应灵敏度的各主要因素,建立了葡萄中链霉素和双氢链霉素残留的快速精准定量分析方法。葡萄样品经磷酸溶液(pH=2)超声提取、Oasis HLB单固相萃取柱富集净化后,采用Waters HSS T3色谱柱(100 mm×2.1 mm, 1.8 μm)分离,柱温35 ℃,进样量2 μL,以0.1%甲酸水溶液-甲醇溶液(60∶40, v/v)为流动相进行等度洗脱,在正离子、电喷雾电离源多反应监测模式下测定,外标法定量。链霉素和双氢链霉素在2~400 μg/L质量浓度范围内线性关系良好,相关系数(R²)分别为0.9991和0.9997;在5、10、20和40 μg/kg 4个添加水平下的平均回收率为76.8%~91.9%,相对标准偏差为0.4%~10.2%;链霉素和双氢链霉素的检出限(LOD)为1 μg/L,定量限(LOQ)为5 μg/kg。为验证该方法的适用性,将方法适用于无籽红提、新郁葡萄、夏黑葡萄等实际样品中进行添加回收实验,链霉素和双氢链霉素的平均回收率分别为77.2%~83.9%和70.8%~78.9%, RSD为3.0%~15.6%。该法的准确度和精密度均符合葡萄中链霉素和双氢链霉素分析要求,且操作简便、准确,灵敏度高,适用于葡萄中链霉素和双氢链霉素残留量的检测分析。     

蜂蜜中链霉素与双氢链霉素残留量的液相色谱串联质谱法测定

建立了液相色谱串联质谱（HPLC-MS/MS）同时对蜂蜜中链霉素和双氢链霉素残留量进行分析的方法。采用磷酸溶液提取,苯磺酸固相萃取柱和C18固相萃取柱串联净化,液相色谱串联质谱测定。链霉素的检出限为0.002 mg/kg,线性范围为0.005～0.100 mg/kg,相关系数为0.9992;双氢链霉素检出限为0.001mg/kg,线性范围为0.002～0.050 mg/kg,相关系数为0.9924。方法回收率为78%～95%,相对标准偏差为2.6%～4.9%。该法实用、准确、快捷,可应用于蜂蜜样品中链霉素和双氢链霉素的同时检测。     

液相色谱法测定番茄制品中链霉素和双氢链霉素的残留量

建立了测定番茄制品中链霉素和双氢链霉素残留量的净化方案.样品中的残留物用磷酸盐缓冲液(pH4)提取,经分散固相萃取法初步净化后,再经串联双柱固相萃取净化,用RPC18(Symmetry Shield)色谱柱在梯度洗脱下分离待测物,外标法定量.链霉素的线性范围为0.05～0.8 mg/L,相关系数r＞0.999 8.方法的回收率为71％～95％,定量限(S/N=10)为0.1 mg/kg,测定结果的相对标准偏差为2.6％～10.5％.该方法操作简便,净化效果好,灵敏、准确,检测成本低,适用于检测和分析番茄制品中链霉素和双氢链霉素的残留量.     

液相色谱-串联质谱法测定鳗鱼中链霉素和双氢链霉素残留量

建立了不使用离子对试剂,液质联用技术检测鳗鱼中链霉素和双氢链霉素残留量的检测方法。样品经三氯乙酸溶液提取,碱性氧化铝快速净化,弱阳离子交换柱固相萃取,CAPCELL PAK ST柱分离。链霉素和双氢链霉素检出限为1.5μg/kg,在10.0~500 ng/m L质量浓度范围内链霉素和双氢链霉素呈线性相关,相关系数为0.9999和0.9994,回收率在78.3%~105.9%之间,相对标准偏差在3.1%~6.6%之间。方法采用碱性氧化铝基质分散固相萃取,除去样液中油脂同时也降低样液中酸的浓度,进而降低固相萃取上样液中碱金属离子强度,提高了链霉素和双氢链霉素残留检测的绝对回收率。     

亲水作用色谱-串联质谱法测定蜂蜜中链霉素和双氢链霉素残留

建立了亲水作用色谱-串联质谱（HILIC-MS/MS）测定蜂蜜中链霉素和双氢链霉素的分析方法。样品中链霉素和双氢链霉素经20 g/L三氯乙酸水溶液（含50 mmol/L磷酸盐，pH 6.8）提取，HLB固相萃取柱净化，采用HILIC-MS/MS对目标物进行定性和定量分析。采用SIELC Obelisc R色谱柱，以0.5%（体积分数）甲酸水溶液和乙腈为流动相进行梯度洗脱分离，在正离子模式下检测，外标法定量。该方法在2.5~100 μg/L范围内线性关系良好（r>0.99），检出限（LOD）为2.0 μg/kg，定量限（LOQ）为5.0 μg/kg。在空白蜂蜜样品中进行5.0、20.0、100.0 μg/kg 3个水平的加标回收试验，方法的平均回收率为86.9%~113.2%，精密度在10%以下。该方法简单、快速、灵敏，重复性好，可用于蜂蜜中链霉素和双氢链霉素的定量测定。     

高效液相色谱-四极杆/线性离子阱质谱测定替米沙坦中N-甲基邻苯二胺残留量

建立了高效液相色谱-四极杆/线性离子阱质谱(HPLC-QTRAP-MS/MS)测定替米沙坦中N-甲基邻苯二胺残留量的分析方法。替米沙坦药物以水-乙腈(80∶20,体积比)溶解后,采用Agilent Eclipse XDB-C18色谱柱(3.5μm,2.1 mm×100 mm)进行分离,以0.1%(体积分数)甲酸水和乙腈作为流动相进行梯度洗脱,电喷雾正离子(ESI+)扫描方式下选择离子监测(SRM)模式对样品进行检测。结果表明,N-甲基邻苯二胺在2.0~50μg/L范围内线性关系良好(r0.99),检出限(S/N=3)为0.5μg/L,定量下限(S/N=10)为2.0μg/L。该方法操作简单、灵敏度高、重现性好,可用于替米沙坦中N-甲基邻苯二胺残留量的测定。     

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.