高效液相色谱对液态奶中三聚氰胺的快速测定

建立了有机溶剂提取和离子对色谱相结合的三聚氰胺快速检测方法.样品中加入有机溶剂振荡提取,取上清液过滤进行高效液相色谱(HPLC)分析.对丙酮、乙腈、乙醇和异丙醇的提取物分别在甲醇-离子对试剂流动相体系和乙腈-离子对试剂流动相体系中进行测定和比较.结果显示,选择合适的流动相,使用丙酮、乙醇或异丙醇为提取剂可以获得较好的提取效果.在甲醇-离子对试剂流动相体系中,三聚氰胺的质量浓度在1.0 ～100.0 mg/L范围内与色谱峰面积呈良好的线性关系(r=0.999 98),检出限为0.1 mg/kg,采用丙酮为提取剂,加标回收率为97% ～103%,相对标准偏差(RSD)小于5%.     

亲水作用色谱-串联质谱法同时测定液态奶中三聚氰酸和三聚氰胺

建立了亲水作用色谱-串联质谱同时测定液态奶中三聚氰酸和三聚氰胺的方法。液态奶样品经体积分数2.5%甲酸溶液提取、离心后乙腈稀释,亲水作用色谱柱分离,电喷雾串联四极杆质谱检测器检测,分别在负、正离子模式下测定三聚氰酸和三聚氰胺。三聚氰酸和三聚氰胺分别在0.5～100μg/L、0.1～50μg/L范围内线性关系良好。在0.25～15mg/kg、0.1～7.5mg/kg添加水平范围内,三聚氰酸平均回收率为84.5%～98.0%(RSD为2.1%～6.1%),三聚氰胺平均回收率为85.5%～88.9%(RSD为3.2～5.8%)。三聚氰酸、三聚氰胺定量限分别为0.25mg/kg、0.1mg/kg。     

高效液相色谱法测定金属涂层罐中9种双酚类环氧衍生物的迁移量

为了评估金属涂层罐中双酚类环氧衍生物的迁移风险,建立高效液相色谱法测定金属涂层罐中9种双酚类环氧衍生物的迁移量。选择水、3%乙酸、10%乙醇、玉米油为食品模拟物;迁移条件:于121℃处理30min后,再于60℃保温10 d;流动相为水–乙腈,梯度洗脱;FLD检测器的激发波长为235 nm,发射波长为312 nm。双酚A-二缩水甘油醚(BADGE)及其衍生物分别在30～10 000μg/L(水、3%乙酸、10%乙醇),30～2 000μg/L (玉米油)范围内与色谱峰面积呈良好的线性关系;双酚F-二缩水甘油醚(BFDGE)及其衍生物分别在100～10 000(水、3%乙酸、10%乙醇),100～2 000(玉米油)范围内与色谱峰面积呈良好的线性关系,相关系数均不低于0.995 0,检出限为0.03mg/L(BADGE及其衍生物)和0.1mg/L(BFDGE及其衍生物),测定结果的相对标准偏差不大于7.39%(n=6),加标回收率为80.32%～113.86%。该方法可用于金属涂层罐中9种双酚类环氧衍生物迁移量的快速检测。     

玩具中苯酚和双酚A的高效液相色谱-荧光检测方法研究

采用高效液相色谱分离,荧光检测器检测,建立了三种不同类型的玩具中苯酚和双酚A的测定方法.用超声提取的方式处理样品,对提取溶剂和提取时间进行选择,确定以甲醇-水(65:35,V/V)作为提取溶液,超声提取20 min.苯酚和双酚A分别在0.012～1.0 mg/L、0.03～2.5 mg/L范围内线性良好,相关系数均达到0.9999,检出限分别为0.6 mg/kg和1.5 mg/kg,不同加标水平的回收率为90.5%～104.3%,其相对标准偏差为0.4%～3.8%.该方法操作简便,灵敏度高、重现性好,能有效提取和测定三类玩具中的苯酚和双酚A.     

高效液相色谱法测定化妆品中5种防腐剂

建立高效液相色谱同时检测化妆品中对羟基苯乙酮、苯氧乙醇、对羟基苯甲酸甲酯、对羟基苯甲酸乙酯、对羟基苯甲酸丙酯5种成分含量的方法。样品经甲醇提取后，经CAPCELL PAK C₁₈色谱柱分离，流动相为乙腈和0.1%磷酸溶液，梯度洗脱，流量为1.0 mL/min，检测波长为270 nm，进样体积为10μL。对羟基苯乙酮和对羟基苯甲酸甲酯的质量浓度在0.1～50 mg/L范围内，苯氧乙醇质量浓度在2.0～1 000 mg/L范围内，对羟基苯甲酸乙酯和对羟基苯甲酸丙酯质量浓度均在0.25～125 mg/L范围内与色谱峰面积具有线性关系良好，相关系数均为0.999 9。在水剂、乳液、膏霜三种基质中，5种成分低、中、高3个浓度水平的平均加标回收率为94.16%～102.87%，测定结果的相对标准偏差为0.9%～6.9%(n=6)。该方法可用于化妆品中对羟基苯乙酮等5种防腐剂的含量检测。     

高效液相色谱法检测食品中多种香料共存时的罂粟壳

 采用高效液相色谱法检测食品中多种香料共存时的罂粟壳。样品经碱化后采用氯仿 乙醇 (体积比为 9∶1)提取 ,在苯基柱上以乙腈 甲醇 水为流动相进行分离 ,外标法定量。罂粟碱 ,吗啡 ,可待因在 1 2mg/L～ 10 0mg/L范围内线性关系良好 ,平均回收率为 79.3%～ 86 .1%。该方法的专属性和准确度较高。     

超高效合相色谱法测定尼龙6食品接触材料中己内酰胺迁移量

建立了超高效合相色谱法测定尼龙6食品接触材料中己内酰胺迁移量的方法。样品经水、4%乙酸(V/V)、50%乙醇(V/V)、正己烷等4种食品模拟物浸泡后,50%乙醇、正己烷浸泡液直接进样,水、4%乙酸经乙醇稀释后进样,采用超临界CO2-甲醇(含2%水)为流动相进行梯度洗脱,经C18色谱柱(3.0 mm×100 mm,1.8μm)分离,通过PDA检测器对目标化合物在210 nm波长下进行分析,外标法定量。在优化条件下,己内酰胺在水、4%乙酸、50%乙醇、正己烷4种食品模拟物中,质量浓度范围分别在5.0~50.0 mg/L,5.0~50.0 mg/L,2.0~50.0 mg/L,5.0~50.0 mg/L线性良好,方法检出限分别为2.0,2.0,1.0,2.0 mg/L。进行添加回收实验,己内酰胺回收率为91.4%~98.4%,相对标准偏差为1.9%~3.2%。方法可用于食品接触材料中己内酰胺迁移量的快速测定。     

毛细管电泳法测定白头翁汤中黄连和黄柏共煎生物碱的煎出量

 建立了利用毛细管电泳简便、准确地测定白头翁汤中黄连和黄柏共煎生物碱煎出量的方法。采用自组装毛细管电泳装置,采用75μmi.d.×50cm弹性石英毛细管,以0 05mol/LNa2B4O7 CH3OH(体积比为85∶15)溶液作缓冲液,运行电压为14kV,检测波长为232nm。另外,通过实验优化了提取溶剂中乙醇的含量。实验结果表明:以小檗碱、巴马汀提取量为指标,30%(体积分数)的乙醇水溶液是提取白头翁汤中黄连和黄柏共煎生物碱的最佳溶剂。小檗碱和巴马汀的质量浓度分别在15 0mg/L～65 0mg/L、12 5mg/L～50 0mg/L时与其峰面积有良好的线性关系;小檗碱的平均回收率不低于95%。     

反相高效液相色谱法同时测定化妆品中7种萘二酚类物质

建立了反相高效液相色谱((RP-HPLC))同时测定化妆品中7种萘二酚类物质的分析方法。膏霜类、乳液类和水类样品用95%(v/v)乙醇提取,粉类样品用95%乙醇-0.1%乙酸(3:2, v/v)溶液提取,经离心、过滤后,用C18柱,以甲醇-0.1%乙酸溶液为流动相梯度洗脱分离,使用二极管阵列检测器检测,以保留时间定性,并以紫外吸收光谱图辅助定性,外标法定量。结果表明,萘二酚类物质在线性范围内线性关系良好,相关系数均不低于0.999 0,方法的定量限(以信噪比为10计)为0.5～1.2 mg/kg,添加水平为5.0～50 mg/kg时回收率为84.0%～102%,相对标准偏差(n=6)为1.3%～5.7%。该法前处理简单、回收率高、精密度好,适用于非蜡基类化妆品中萘二酚类物质的测定。     

气相色谱-质谱法测定聚氯乙烯包装材料和食品模拟物中的46种增塑剂

建立了46种增塑剂在聚氯乙烯(PVC)食品包装材料中的含量及其在水、3%乙酸、10%乙醇和橄榄油4种食品模拟物中迁移量的气相色谱-质谱(GC-MS)测定方法。食品包装材料、水质模拟物和橄榄油中增塑剂分别采用溶解-沉淀法、正己烷液-液萃取和凝胶渗透色谱(GPC)法提取。采用GC-MS法,在选择离子监测模式(SIM)下对46种增塑剂进行定性,采用外标法进行定量测定。各种增塑剂在0.1～2.0 mg/L质量浓度范围内呈线性,相关系数为0.9910～0.9999,各组分检出限均在0.005～0.05 mg/kg之间。在2种食品模拟物中,3个浓度添加水平下46种增塑剂的加标回收率在69.51%～107.21%之间,精密度(RSD, n=6)为3.53%～18.95%。该方法可满足PVC食品接触制品及4种不同性质的食品模拟物中多种类增塑剂的快速筛查和准确定性、定量测定要求。     

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.