高效液相色谱-蒸发光散射检测法测定烟草中的水溶性糖

采用Waters高效糖分析柱,梯度洗脱分离,建立了高效液相色谱-蒸发光散射检测法（HPLC—ELSD）同时测定烟草中水溶性糖的新方法。乙腈-水为流动相,流速1．0mL／min,柱温30℃,蒸发光散射检测器漂移管温度80℃,氮气作载气,流速2．00L／min。水溶性糖的线性范围：鼠李糖、果糖、葡萄糖、蔗糖0．5—30μg,检出限低于12．5ng;木糖、阿拉伯糖、甘露糖、麦芽糖0．5—20μg,检出限低于25．0ng。8种水溶性糖的加标回收率范围为86．0％～102．4％;相对标准偏差（n=5）皆小于4．1％。     

超高效液相色谱法测定卷烟烟丝中7种水溶性糖含量

以ACQUITY UPLC BEH Amide柱为分析柱,乙腈－0．2％三乙胺一水作为流动相,建立了超高效液相色谱－蒸发光散射检测器测定卷烟烟丝中鼠李糖、木糖、果糖、甘露糖、葡萄糖、蔗糖、麦芽糖7种水溶性糖的分析方法。7种水溶性糖回归方程的线性相关系数均大于0．999,检出限为0．56～1．11μg／mL。7种水溶糖的回收率在90．43％106．41％之间,相对标准偏差为1．66％－4．35％仰：6）。该方法灵敏度、准确度高,稳定性好,可用于大批量卷烟烟丝中水溶性糖含量的测定。     

烟草中水溶性糖的超高效液相色谱分析及聚类分析研究

以ACQUITY UPLC BEH Amide柱为分析柱,乙腈(0.2%TEA)和水作为流动相,采用蒸发光散射检测器,建立了超高效液相色谱分析烟草中鼠李糖、木糖、果糖、甘露糖、葡萄糖、蔗糖、麦芽糖的方法.7种水溶糖的加标回收率在85.2%～105.3%之间,相对标准偏差皆小于5.7%.方法可用于烟草及其制品中水溶性糖含...     

高效液相色谱法测定浓缩果汁中5种可溶性糖

建立同时测定浓缩果汁中木糖、果糖、葡萄糖、蔗糖和麦芽糖的高效液相色谱–蒸发光散射检测方法(HPLC–ELSD)。样品采用乙腈–水(50∶50)稀释,用酰胺键合色谱柱BEH Amide分离,蒸发光散射检测器检测,在10 min内完成木糖、果糖、葡萄糖、蔗糖、麦芽糖的分离。浓缩果汁中5种可溶性糖的质量浓度在0.1～2.0 mg/m L与色谱峰面积均呈线性关系,相关系数为0.991 0～0.993 1,检出限为0.23%～0.98%,样品加标回收率为88.6%～104.3%,测定结果的相对标准偏差为2.2%～6.3%(n=6)。该方法快速、准确,可作为浓缩果汁中糖含量的质量控制方法。     

高效液相色谱-蒸发光散射法测定食品中的单糖、双糖、低聚果糖和糖醇

建立了食品中常用的木糖、果糖、葡萄糖、蔗糖、麦芽糖、乳糖、蔗果三糖、蔗果四糖、蔗果五糖、赤藓糖醇、木糖醇、甘露糖醇、麦芽糖醇等13种单糖、双糖、低聚果糖和糖醇的高效液相色谱同时分离检测的方法。该法采用NH₂色谱柱,以乙腈-水为流动相梯度洗脱,蒸发光散射检测器检测;13种糖在0.1~5 g/L内均具有良好的线性关系,检出限均在0.1 g/L以下,精密度(RSD)为2.69%~7.21%,回收率为96.1%~105.2%,结果较为理想。将该法用于实际样品检测,结果显示食品标签明示和实际成分相差较大。     

高效液相色谱/蒸发光散射检测法同时测定饲料中12种甜味剂

建立了饲料中鼠李糖、木糖、果糖、葡萄糖、甜菊双糖苷、蔗糖、麦芽糖、乳糖、蔗果三糖、棉籽糖、蔗果四糖、水苏糖共12种甜味剂的高效液相色谱同时分离检测方法。采用XB-NH2柱分离,以乙腈-水为流动相梯度洗脱,蒸发光散射检测器进行测定。结果表明,12种甜味剂在0.05~5 g/L范围内均具有良好的线性关系,相关系数为0.996 3~1.000 0,检出限不大于0.04 g/L,方法的回收率为86.6%~112%,相对标准偏差(RSD)为0.5%~6.7%。该方法简单快速,定量准确可靠,适用于饲料中甜味剂的日常检测。     

高效液相色谱-蒸发光散射检测法测定烟草中水溶性糖

采用水浴浸取法提取烟草中的糖,以Zorbax糖分析柱(柱温为30℃)、乙腈:水(80：20,V／V)为流动相和蒸发光散射检测器分离测定烟草中果糖、葡萄糖、蔗糖和麦芽糖的含量。4种糖在含量80～l000mg／L范围内与其色谱峰面积之间具有良好的线性关系,检出限分别为2．0mg／L,1．6mg／L,1．6mg／L,2．0mg／L。     

超高效液相色谱-蒸发光散射检测法测定蜂蜜中12种糖组分

建立了蜂蜜中果糖、葡萄糖、蔗糖、松二糖、麦芽酮糖、麦芽糖、曲二糖、异麦芽糖、吡喃葡糖基蔗糖、松三糖、蜜三糖和麦芽三糖含量的超高效液相色谱－蒸发光散射测定方法。试样经去离子水溶解,乙腈定容,用0.22 μm滤膜过滤后,采用Amide色谱柱分离,蒸发光散射检测器检测,外标法定量。在优化实验条件下,12种糖得到良好分离,线性相关系数为0.997 7～0.999 8,果糖和葡萄糖的检测结果与示差折光检测法无显著性差异,其余10种糖的平均回收率为90.0 %～105 %,相对标准偏差为0.70%～5.8%。该方法灵敏度高,准确度高,重复性好,适用于蜂蜜中多种糖组分的同时定量分析。用于72批不同蜜种蜂蜜样品中糖组分的检测,发现中国主要蜜源蜂蜜中普遍含有松二糖、麦芽酮糖、麦芽糖等糖组分。该方法和检测数据可为蜂蜜品质和质量评价提供重要支撑。     

柱前衍生化-高效液相色谱法分析木糖结晶母液的单糖组成

采用1-苯基-甲基-吡唑啉酮(PMP)柱前衍生化-反相高效液相色谱(HPLC)法建立了8种常见单糖的分离模式,并用于木糖结晶母液单糖组成的定量分析.结果表明:木糖结晶母液至少由甘露糖、鼠李糖、纤维二糖、葡萄糖、半乳糖、木糖、阿拉伯糖及岩藻糖8种单糖组成,其中以葡萄糖、半乳糖、木糖和阿拉伯糖为主.以峰高定量,8种单糖的浓...     

高效液相色谱法分析蜂蜜中的糖

本文研究了用四乙撑五胺（简称ＴＥＰＡ）作为胺基改善剂，在硅胶柱上定量分析蜂蜜含糖量的方法，并成功地分离了木糖、果糖、葡萄糖、蔗糖、麦芽糖和乳糖。对操作条件进行了探讨。采用示差折光检测器检测，含０．０１％ＴＥＰＡ的乙腈－水（７７＋２３）作流动相。六种糖的相对标准偏差均小于３．５％。     

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.