吖啶红-罗丹明B荧光共振能量转移法测定汞

研究了吖啶红(供体)和罗丹明B(受体)之间荧光共振能量转移的最佳条件,建立了荧光共振能量转移猝灭法测定污水和废旧电池中痕量汞的方法。室温中,采用十六烷基三甲基溴化胺(CTMAB),在pH=7.0条件下,吖啶红与罗丹明B之间能产生有效的共振能量转移,汞离子的加入能使体系中罗丹明B荧光峰强猝灭从而测定汞的含量。汞离子浓度在0.05～2.5μg/mL范围内与罗丹明B荧光强度变化ΔF呈现良好线性关系(r=0.9997),检出限(3σ/K)为0.95ng/mL,加标回收率98.0%～104.5%。该方法可用于污水和废旧电池中痕量汞的测定。     

纳米固相微萃取应用于干红辣椒、水果饮料及红酒中罗丹明B的定量分析

制备了一种新型的聚苯乙烯纳米纤维, 将其作为固相萃取吸附剂装填制成固相萃取柱, 与高效液相色谱联用建立了干辣椒、 水果饮料及红酒中罗丹明B的定量分析方法. 高效液相色谱以3 g/L磷酸缓冲液-甲醇混合溶液(体积比3∶7, pH=7.0)为流动相. 通过对提取条件的优化, 得到该方法对干辣椒中罗丹明B的检出限为0.1 ng/g, 最低定量限为0.6 ng/g; 对水果饮料和红酒中罗丹明B的检出限均为0.2 ng/mL, 最低定量限均为0.5 ng/mL. 此方法对干辣椒中罗丹明B的提取回收率为98.2%~110.3%; 对水果饮料中罗丹明B的提取回收率为94.6%~102.2%; 对红酒中罗丹明B的提取回收率为90.4%~104.6%. 该方法的线性范围为1~100 ng/mL(ng/g), 相对标准偏差为2.3%~9.0%. 该方法灵敏度高、 选择性好, 可用于干辣椒、 水果饮料及红酒中罗丹明B的定量分析.     

纳米固相微萃取应用于干红辣椒、水果饮料及红酒中罗丹明B的定量分析（英文）

制备了一种新型的聚苯乙烯纳米纤维,将其作为固相萃取吸附剂装填制成固相萃取柱,与高效液相色谱联用建立了干辣椒、水果饮料及红酒中罗丹明B的定量分析方法.高效液相色谱以3 g/L磷酸缓冲液-甲醇混合溶液(体积比3∶7,pH=7.0)为流动相.通过对提取条件的优化,得到该方法对干辣椒中罗丹明B的检出限为0.1 ng/g,最低定量限为0.6 ng/g;对水果饮料和红酒中罗丹明B的检出限均为0.2 ng/m L,最低定量限均为0.5 ng/m L.此方法对干辣椒中罗丹明B的提取回收率为98.2%~110.3%;对水果饮料中罗丹明B的提取回收率为94.6%~102.2%;对红酒中罗丹明B的提取回收率为90.4%~104.6%.该方法的线性范围为1~100 ng/m L(ng/g),相对标准偏差为2.3%~9.0%.该方法灵敏度高、选择性好,可用于干辣椒、水果饮料及红酒中罗丹明B的定量分析.     

罗丹明B分子印迹聚合物微球的合成及其在固相萃取中的应用

以罗丹明B为模板分子,丙烯酰胺为功能单体,乙二醇二甲基丙烯酸酯为交联剂,采用沉淀聚合法制备了罗丹明B分子印迹聚合物(MIP)微球,并用扫描电子显微镜表征。 采用紫外分光光度法测定了印迹分子罗丹明B与功能单体丙烯酰胺二者之间的结合常数(K=5.303×103 (mol/L)-1)和化学计量比(n=1)。 考察了沉淀剂的种类和用量对聚合物微球的影响。 将分子印迹聚合物微球应用于固相萃取材料自制固相萃取柱,从加标罗丹明B的红椒粉中萃取罗丹明B。 本文优化了固相萃取条件,高效液相色谱检测表明,在一定的萃取条件下,分子印迹聚合物对加标量为0.479 mg/kg的辣椒中罗丹明B的萃取加标回收率可达91.7％～103.5%。     

罗丹明B分子印迹固相萃取小柱的研制及应用

研制一种对罗丹明B具有特异性识别性能的分子印迹固相萃取小柱。用沉淀聚合法制备罗丹明B分子印迹聚合物,通过静态平衡吸附实验及固相萃取实验表征其性能,并对市售辣椒样品中的罗丹明B进行测量。罗丹明B模板聚合物的吸附能力明显优于空白聚合物;印迹固相萃取小柱对罗丹明B标准溶液(0.05 mmol/L)一次性萃取率为98.24%,实际样品测量的回收率为90.0%~95.0%,测定结果的相对标准偏差为0.9%~1.7%(n=3)。罗丹明B分子印迹固相萃取小柱选择性好、萃取率高,可应用于食品、化妆品检测等相关领域。     

高效液相色谱-荧光检测法测定辣椒制品中5种罗丹明染料北大核心CSCD

建立了辣椒制品中罗丹明110、磺酰基罗丹明B、罗丹明B、罗丹明6G和丁基罗丹明B 5种罗丹明染料的高效液相色谱-荧光检测法。方法采用Zorbax SB-C18柱(250×4.6mm,5.0μm),以乙腈和水(均含0.1%的甲酸)为流动相进行梯度洗脱,5种组分可基线分离。结果表明,5种罗丹明染料在相应浓度范围内线性关系良好,线性相关系数均大于0.999,平均加标回收率在84.0%~105.8%之间,相对标准偏差为1.2%~4.8%。该方法简单、准确、灵敏度高,适用于辣椒制品中罗丹明染料含量的同时测定。     

砷钼杂多酸/罗丹明B三元离子缔合物的二级散射光谱研究

在0.12 mol/L H2SO4介质中,As(Ⅴ)、Mo(Ⅵ)与罗丹明B形成砷钼杂多酸/罗丹明B三元缔合物,它在λex/λem为325 nm/650 nm波长处产生一个灵敏的二级散射峰.据此建立了一个测定1～20 ng/mL As的二级散射光谱分析新方法.本法具有灵敏度高、选择性好、操作简便等特点.     

超高效液相色谱-四极杆-飞行时间质谱法测定辣椒中多种禁用着色剂

建立了一种超高效液相色谱-四极杆-飞行时间质谱(UPLC-Q-TOF-MS)测定辣椒中多种禁用着色剂的方法。样品采用乙腈和正己烷提取,QuEChERS法净化,利用UPLC法分离,在电喷雾正离子及TOF-MS触发TOF-MS/MS的模式下检测,以保留时间、一级离子质量准确度、一级离子同位素分布、二级碎片与库匹配4种手段确保准确定性分析,以TOF-MS提取离子的峰面积定量。结果表明,23种着色剂在10～500 ng/mL浓度范围内线性关系良好,相关系数为0.9411～0.9989,方法定量限为10～100μg/kg,3个添加水平的回收率为61.82%～103.25%,相对标准偏差(n=8)为2.08%～10.56%。该方法具有快速、灵敏、准确和高通量等优点,可应用于实际辣椒样品中多种禁用着色剂的日常检测。     

高效液相色谱法测定武力拔寒散中橙皮苷的含量

建立液相色谱测定武力拔寒散中橙皮苷含量的方法。以甲醇为流动相A,以冰乙酸–水(1∶300)为流动相B,进行梯度洗脱,检测波长为284 nm,流量为1.0 m L/min,柱温为30℃。橙皮苷的质量浓度在1.190 3~119.03μg/mL范围与色谱峰面积线性关系良好(r=0.999 9),检出限为300 ng/g。样品加标回收率为95.00%~98.50%,测定结果的相对标准偏差为1.0%(n=6)。该方法简单、快速、准确,重现性好,可为全面评价和控制武力拔寒散制剂的质量提供依据。     

磁性固相萃取-高效液相色谱法测定葡萄酒中罗丹明B的含量

样品溶液(pH 4.0,10 mL)以流量1.0 mL·min~(-1)经自制磁性石墨烯(CoFe_2O_4-G)20mg萃取,用1mL丙酮洗脱。所得溶液中的罗丹明B采用高效液相色谱法进行测定。罗丹明B的质量浓度在0.50~10μg·L~(-1)内与其峰面积呈线性关系,检出限(3S/N)为0.08μg·L~(-1)。按标准加入法进行回收试验,回收率为99.0%~101%,相对标准偏差(n=11)为1.6%~4.0%。     

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.     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

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.     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.