辐照肉制品中2-十二烷基环丁酮的测定

采用GB/T 21926-2008《辐照含脂食品中2-十二烷基环丁酮测定气相色谱/质谱法》对辐照肉制品中的2-十二烷基环丁酮进行测定,鉴别辐照肉制品。样品用索氏抽提,经冷冻离心和弗罗里硅土层析净化,用气相色谱质谱联用法测定。2-十二烷基环丁酮的浓度在0.01~0.5 mg/L与色谱峰面积呈良好的线性关系,r=0.999 6。对未经辐照的样品进行加标回收试验,加标回收率为83.1%~94.0%,测定结果的相对标准偏差小于6%(n=6)。     

加速溶剂萃取-气相色谱-串联质谱法测定党参中69种农药残留量

采用加速溶剂萃取-气相色谱-串联质谱法测定党参中69种农药残留量。样品以乙腈为溶剂经加速溶剂提取,提取液用Carb/NH2固相萃取小柱净化。在气相色谱分离中用VF-5MS柱为固定相,在质谱分析中采用多反应监测模式。69种农药在一定的质量浓度范围内与其峰面积呈线性关系,方法的测定下限(10S/N)在0.03~21.2μg·kg-1之间。在20,100,200μg·kg-1等3个浓度水平进行加标回收试验,回收率在63.8%~110%之间,测定值的相对标准偏差(n=6)在1.9%~13%之间。     

固相萃取-气相色谱-质谱法测定土壤中阿特拉津

应用固相萃取-气相色谱-质谱法测定土壤中阿特拉津的含量。土壤样品采用索氏提取,硅胶固相萃取小柱净化。在气相色谱分离中用TR-5MS色谱柱为固定相,在质谱分析中采用选择离子检测模式。阿特拉津的质量浓度在5.00~200μg·L-1范围内与其峰面积呈线性关系,检出限为0.32ng·g-1。加标回收率在88.2%~90.7%之间,测定值的相对标准偏差(n=10)为4.8%。     

加速溶剂萃取/GC-MS法对辐照肉类食品中2-十二烷基环丁酮的检测

应用加速溶剂萃取(ASE)/气相色谱-质谱(GC-MS)技术建立了辐照肉类食品中2-十二烷基环丁酮(2-DCB)的检测方法.采用加速溶剂萃取法从辐照过的肉类样品中提脂,萃取液加入乙腈后冰箱冷冻去除脂肪,LC-Si固相萃取小柱净化,氮气吹干后加入内标定容,于GC-MS仪上测定,在0.1 ～0.4 μg/g(以脂肪计)范围内的回收率为78% ～92%,RSD小于11%,定量下限为0.1 μg/g(以脂肪计).同时采用该方法对辐照剂量为1 ～8 kGy的猪肉、鸡肉和鱼肉进行检测,再次证明了辐照剂量与脂肪中2-DCB含量存在线性相关关系.     

液液萃取-气相色谱-质谱法测定墨水中的16种多环芳烃

采用液液萃取-气相色谱-质谱法测定墨水中的16种多环芳烃。样品经二氯甲烷液液萃取后,使用固相萃取技术进行纯化。在气相色谱分离中用DB-5MS色谱柱为固定相,在质谱分析中采用选择离子监测模式。16种多环芳烃在一定的质量浓度范围内与其峰面积呈线性关系,方法的检出限(3S/N)在5.0~30μg·kg-1之间。以空白样品为基体进行加标回收试验,所得回收率在60.6%~116%之间,测定值的相对标准偏差(n=6)在1.5%~5.3%之间。     

气相色谱-质谱法测定蔬菜和水果中螺虫乙酯的残留量

采用气相色谱-质谱法测定蔬菜和水果中螺虫乙酯的残留量。蔬菜或水果样品经乙腈均质提取,以乙二胺-N-丙基硅烷和十八烷基硅烷为基质分散固相萃取剂净化。在气相色谱分离中用HP-5MS毛细管色谱柱为固定相,在质谱分析中采用选择离子监测模式。螺虫乙酯的质量浓度在10~500μg·L~(-1)内与其对应的峰面积呈线性关系,方法的检出限(3S/N)为0.75μg·kg~(-1),测定下限(10S/N)为2.51μg·kg~(-1)。以空白样品为基体进行加标回收试验,所得回收率为79.8%~101%,测定值的相对标准偏差(n=6)为4.1%~8.7%。     

固相萃取-在线凝胶渗透色谱-气相色谱-质谱法测定豆芽中53种农药残留量

采用固相萃取-在线凝胶渗透色谱-气相色谱-质谱法测定豆芽中53种农药残留量。豆芽样品以乙酸-乙腈(1+99)混合液提取,固相萃取小柱净化,采用在线凝胶渗透色谱-气相色谱分离,在质谱分析中采用选择离子监测模式。53种农药的质量浓度均在0.01~1.0mg·L-1范围内与其峰面积呈线性关系,方法的检出限在0.1~6.0μg·kg-1之间。在20,50,100μg·kg-1等3个浓度水平进行加标回收试验,回收率在72.3%~104%之间,测定值的相对标准偏差(n=6)在1.6%~6.6%之间。     

直接溶剂萃取/气相色谱-质谱检测辐照牛肉中的2-十二烷基环丁酮

应用直接溶剂萃取/气相色谱-质谱技术,建立了辐照牛肉中2-十二烷基环丁酮(2-Dodecylcyclobu-tanone,2-DCB)的快速检测方法。5 g牛肉糜与7 g无水Na2SO4混合均匀后,加入150 mL乙腈,搅拌提取2 min,提取液过滤转移至500 mL圆底烧瓶中,提取重复2次,将提取液旋转蒸干,用正己烷清洗烧瓶并收集,定容至50 mL,取10 mL氮吹浓缩至1 mL,用硅胶固相萃取小柱(1 g,6 mL)净化,淋洗液经氮气吹干后用正己烷定容至1 mL,取1μL供气相色谱-质谱测定。本方法检出限为0.004 mg/kg,定量限为0.01 mg/kg;牛肉糜中2-DCB添加浓度在0.01～0.50 mg/kg范围内的回收率为87.9%～91.6%,相对标准偏差小于7%,样品前处理仅需60～90 min。采用本方法对辐照剂量为0.5～7.0 kGy的牛肉进行检测,表明辐照剂量与牛肉中2-DCB含量存在线性相关关系(y=0.0608x-0.0004,相关系数R2=0.9899)。     

固相萃取-衍生化-气相色谱-质谱法测定水中类固醇类雌激素

采用固相萃取-衍生化-气相色谱-质谱法同时测定水中4种类固醇类雌激素雌酮(E1)、17β-雌二醇(E2)、17α-乙炔基雌二醇(EE2)、雌三醇(E3)。样品经Oasis HLB固相萃取柱,以丙酮为溶剂进行洗脱后,采用吡啶、N-甲基-N-三甲基硅基三氟乙酰胺于40℃衍生化20min后,采用气相色谱-质谱仪分析。E1、E2、EE2和E3的线性范围分别为5.00~500μg·L-1和10.0~500μg·L-1,4种类固醇类雌激素的检出限(3S/N)在1.5~3.0μg·L-1之间,测定下限(10S/N)在5.0~10μg·L-1之间;方法用于实际水样的分析,加标回收率在86.8%~93.8%之间,测定值的相对标准偏差(n=7)在7.1%~11%之间。     

分散固相萃取-气相色谱-质谱法测定地表水中的异味物质

研究了分散固相萃取-气相色谱质谱法测定地表水中土臭素、2-甲基异茨醇、β-环柠檬醛、β-紫罗兰酮、2,4,6-三氯苯甲醚、2-异丙基-3-甲氧基吡嗪、2-异丁基-3-甲氧基吡嗪的方法。确定最佳分散固相萃取条件,在优化试验条件下对异味物质的测定结果显示,该方法重现性好,精密度高,7种异味物质的质量浓度均在0.05~10.0μg·L-1范围内与峰面积呈线性关系,方法的检出限(3S/N)在1~5ng·L-1之间。应用本方法对空白加标水样进行测定,回收率在81.6%~98.4%之间,测定值的相对标准偏差(n=5)在7.1%~14%之间。     

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.