亲水色谱-串联质谱法对牛奶与奶粉中三聚氰胺及其衍生物含量的测定

建立了牛奶和奶粉中三聚氰胺及其3种衍生物（三聚氰酸、三聚氰酸一酰胺、三聚氰酸二酰胺）的亲水色谱-串联质谱检测方法（HILIC-MS/MS）。牛奶样品直接用乙腈超声波提取;奶粉样品先用水溶解后再加乙腈超声波提取,高速离心后以乙腈-水为流动相,采用亲水作用色谱柱分离这4种化合物,在电喷雾正、负电离切换多反应监测模式下进行定性与定量分析,三聚氰酸一酰胺与三聚氰酸二酰胺含量在50～10000μg/kg之间、三聚氰胺与三聚氰酸在25～5000μg/kg之间,均获得良好的线性。方法检出限（LOD）为5～20μg/kg,定量下限（LOQ）为50～100μg/kg,3个添加水平的平均回收率为81%～97%。该方法简便、快速、准确,可满足牛奶及奶粉中三聚氰胺、三聚氰酸、三聚氰酸一酰胺、三聚氰酸二酰胺测定的需要。     

应用亲水作用色谱检测鸡蛋和肉中三聚氰胺及三聚氰酸二酰胺

应用亲水作用色谱(HILIC)对从市场上购买的鸡蛋和肉中的三聚氰胺及三聚氰胺降解产物三聚氰酸二酰胺进行了检测。采用的色谱柱为ZIC-HILIC柱,流动相为3 mmol/L磷酸二氢铵溶液(pH 6.9)-乙腈(20:80, v/v),流速为0.8 mL/min,检测波长为220 nm。在该体系下,三聚氰胺和三聚氰酸二酰胺的保留时间适中,与样品中的内源性物质有良好的分离。样品经0.1%磷酸提取,偏磷酸及乙腈沉淀蛋白质和糖类物质,以及P-SCX固相萃取柱净化。三聚氰胺和三聚氰酸二酰胺在0.4～40 mg/L范围内与峰面积呈良好的线性关系,样品定量限(按信噪比(S/N)不小于10计)为2 mg/kg,在2～10 mg/kg添加水平下的平均回收率为80%～105%,相对标准偏差小于10%。该方法具有良好的分离选择性,可用于鸡蛋和肉中三聚氰胺和三聚氰酸二酰胺的同时检测。     

亲水作用色谱-串联质谱同时检测食品接触材料中三聚氰胺及其衍生物迁移量

建立了亲水作用色谱-串联质谱(HILIC-MS/MS)法同时测定食品接触材料中三聚氰胺(MEL)、三聚氰酸一酰胺(ADE)和三聚氰酸(CYA)的方法。食品接触材料分别采用水、4%乙酸、10%乙醇和橄榄油在70℃烘箱浸泡4h。水基浸泡液过0.45μm微孔薄膜后进入色谱柱,橄榄油提取物以凝胶色谱法净化后进入色谱柱。在优化条件下,亲水作用色谱柱分离,电喷雾串联四极杆质谱检测器检测,分别在正、负离子模式下测定。MEL、ADE和CYA分别在5～100、2～200、2～200μg/L范围内线性关系良好(R>0.999)。检出限分别为4.0、8.0、8.0μg/L。在5.0μg/L的添加水平下,MEL、ADE、CYA的平均回收率在98.9%～106.3%之间,相对标准偏差在2.49%～5.44%之间。结果表明,该法可简便、快速、准确地同时测定食品接触材料中三聚氰胺及其衍生物的迁移量。     

HPLC同时检测食品接触材料中三聚氰胺与三聚氰酸单体迁移量

建立了一种用液相色谱技术检测分析食品接触材料中三聚氰胺与三聚氰酸单体迁移量的方法.样品采用水、4%乙酸和10%乙醇3种模拟物进行浸泡.色谱分离采用Phenomenex Luna NH2柱,柱温:30 ℃,流动相为乙腈-5 mmol/L,pH=6.5 PBS缓冲溶液(75∶25,V/V),流速1.0 mL/min,DAD...     

固相萃取-亲水相互作用色谱/串联质谱法同时测定食品中三聚氰胺和三聚氰酸

建立了固相萃取-亲水相互作用色谱/串联质谱同时测定食品中三聚氰胺和三聚氰酸残留量的方法。采用乙腈和水提取试样中残留的三聚氰胺和三聚氰酸,正己烷脱脂,提取液经亲水性键合硅胶和阳离子交换树脂复合填料柱(MCT柱)净化。采用亲水相互作用色谱柱进行分离,质谱采用正、负离子切换模式电离,多反应监测模式检测,同位素内标法定量。三聚氰胺和三聚氰酸在10～2500 μg/L范围内呈线性相关,相关系数(r)均大于0.99,定量限分别为25和50 μg/kg。本方法在动物源性食品、植物源性食品、乳及乳制品等不同样品中的三聚氰胺和三聚氰酸高、中、低3个添加水平的回收率分别在70.0%～129.6%和70.0%～128.6%之间,相对标准偏差分别在1.4%～23.3%和2.8%～18.7%之间。该方法可满足食品中三聚氰胺和三聚氰酸同时定量测定的需要。     

基质分散固相萃取-高效液相色谱-串联质谱法快速测定婴幼儿配方乳粉中19种非蛋白氮化合物

建立了基质分散固相萃取-高效液相色谱-串联质谱法同时检测婴幼儿配方乳粉中的三聚氰胺、灭蝇胺、脒脲、氨基三嗪、3-氨基三唑、4-氨基三唑、三聚氰酸、双氰胺、硫脲、氨基脲、L-亮氨酸、L-异亮氨酸、L-精氨酸、L-羟脯氨酸、三聚氰胺一酰胺、三聚氰胺二酰胺、胍、尿囊素、L-茶氨酸等19种非蛋白氮化合物的方法。样品用甲酸沉淀蛋白,三氯甲烷除去脂肪,乙腈提取,无水硫酸镁去除多余水分, C18净化,Merck ZIC HILIC 色谱柱(150 mm ×2.1 mm,5μm,200魡)分离,梯度洗脱,电喷雾离子化正离子模式(ESI+)和负离子模式( ESI-)同时扫描,多反应监测模式进行检测。其中,尿囊素采用外标法定量,其余18种化合物采用内标法定量。本方法对19种化合物的线性相关系数( r)均大于0.99,定量限( LOQ)为0.05~5.0 mg/kg,回收率为82.2%~115%, RSD<20%。     

指数程序薄涂色谱柱的性能及用于己二酸的分析

在气相色谱分析中,有关程序涂渍色谱柱的研究已有报道,这种色谱柱较适合于厚涂柱的分析。本文所研制的指数程序薄涂色谱柱及分析应用,尚未见报道。该色谱柱是将一根色谱柱分成几段,将每段的固定液涂渍量按指数函数y=m~i(i=1,2,3)变化,而每段固定液量都不超过1％,色谱柱选定为1m。由于固定液量少,且采用指数程序涂渍,因此,色谱操作柱温可较低,分离效能较高,组分的保留时间短,很适合较高沸点、易分解化合物的直接快速分析。 此色谱柱应用于实际样品中己二酸(沸点为330℃,近沸点时分解)的分析,己二酸于160℃下出峰快,保留时间短,峰形较对称,容易定量。其最小检测量为0.80μg,回收率为101.5％,相对标准偏差为±5.9％。 实验部分 (一)主要仪器与色谱条件 1.仪器 上海103气相色谱仪,热导池检测器,岛津C-R3A数据处理机。 2.色谱条件 色谱柱为1m×0.3mm不锈钢柱;固定液为QF-1按0.34％、0.49％、0.7％涂渍;载体为硅烷化玻璃微球(80～100目);载气(H_2)流速40ml/min;桥流150mA;汽化温度172℃;柱温160℃;检测温度170℃。 (二)试剂     

二氢麦角碱在极性嵌入反相色谱固定相上的分离行为

二氢麦角碱的4种组分具有不同的药效特性,需适当的分析方法对其在不同剂型药品中的含量进行分析.传统液相色谱方法使用强碱性流动相,严重腐蚀硅胶基质色谱填料,影响色谱柱寿命.合成了极性嵌入反相固定相--C18酰胺固定相,并在中性流动相条件下分离4种组分.考察了流动相组成和pH对二氢麦角碱在C18酰胺固定相上保留行为的影响.在150 mm×4.6 mm I.D.的C18酰胺色谱柱上,流动相为乙腈-20 mmol/L Na2HPO4(30:70,V/V,pH 7.0)的条件下实现了4种组分的基线分离.与传统方法相比,极性嵌入反相固定相可以有效的改善碱性化合物的分离特性和大幅度地延长色谱柱的使用寿命.     

高效液相色谱法同时测定三氯异氰脲酸(粉)中三聚氰酸和三聚氰胺的含量

建立高效液相色谱法同时测定三氯异氰脲酸(粉)中三聚氰酸和三聚氰胺含量的方法.采用HILIC Silica色谱柱(150 mm×4.6 mm,5 μm),以乙腈-10 mmol/L乙酸铵水溶液(9∶1)为流动相,用紫外检测器在213 nm波长处进行检测.三聚氰酸和三聚氰胺的浓度分别在9.22～92.2 μg/mL和10.92～109.2 μg/mL范围内与对应的峰面积呈良好的线性关系.三聚氰酸和三聚氰胺测定结果的相对标准偏差分别为0.3%、0.4%(n=6).在80%、100%、120%3个添加水平下三聚氰酸的平均回收率分别为117.41%、119.85%、114.40%.     

高效液相色谱法检测食品接触材料中三聚氰酸的残留量

建立了一种用液相色谱技术检测分析食品接触材料中三聚氰酸残留量的方法。样品采用体积分数为10%的乙醇溶液作为提取溶液,超声提取。色谱分离采用氨基色谱柱,流动相为乙腈-磷酸盐缓冲溶液(体积比为75∶25),二极管阵列检测器检测。在优化条件下,三聚氰酸质量浓度在0.5～50 mg/L范围内与色谱峰面积线性关系良好,检出限(S/N=3)为0.1 mg/L。在0.1%的添加水平下,三聚氰酸的回收率在80%～93%之间,测定结果的相对标准偏差为1.36%～2.54%(n=6)。揭示了原料中三聚氰酸残留量与成型品的三聚氰酸迁移量的正相关关系。结果表明,该法简便、快速,可准确测定食品接触材料中三聚氰酸残留量。     

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.