MEKC在线推扫富集法检测蔬菜中残留甲基对硫磷

建立胶束电动色谱在线推扫富集法检测蔬菜中残留的痕量甲基对硫磷。讨论了十二烷基硫酸钠(SDS)浓度、NaH2PO4浓度、缓冲液pH、有机溶剂添加量、样品中电解质浓度、运行电压、进样压力对富集效果的影响;考察了活性炭净化对回收率的影响。结果:选择20 mmol/L磷酸二氢钠+180 mmol/LSDS(pH=6.2),甲醇10%(体积分数)为缓冲液,电压7 kV,进样压力2 062.5KPa×s。1.8 g活性炭的加入对回收率没有明显的影响。甲基对硫磷在0.03 mg/L~2.5 mg/L范围内线性关系良好,相关系数为0.999 6,检测限为0.011 5 mg/L。加标水平在0.4 mg/kg~0.6 mg/kg范围内,回收率为90.44%~90.63%,RSD为1.12%~1.16%。胶束电动色谱在线推扫富集法可用于蔬菜中残留痕量农药的检测。     

胶束电动毛细管电泳法分离检测五种β-内酰胺类抗生素

采用毛细管电泳法,基于胶束电动模式与有机添加剂协同作用,分离检测5种β-内酰胺类抗生素。考察运行缓冲液的构成及各组分浓度、pH值、分离电压等因素对电泳分离的影响。优化后的电泳运行缓冲液包含20mmol/L Na2HPO4-20mmol/L NaH2PO4 (pH8.5),20mmol/L十二烷基硫酸钠和体积分数25%甲醇。在18kV电压下5种抗生素在15min内达到基线分离。各组分线性关系良好,检出限5.3～8.1mg/L,进样精密度RSD 3.8%～5.5%。研究表明,对分子结构特别相近的抗生素,通过表面活性剂胶束准固定相与有机添加剂协同作用来改善分离效果是可行的。     

胶束电动毛细管电泳法分离检测5种β-内酰胺类抗生素

采用毛细管电泳法,基于胶束电动模式与有机添加剂协同作用,分离检测5种β-内酰胺类抗生素。考察运行缓冲液的构成及各组分浓度、pH值、分离电压等因素对电泳分离的影响。优化后的电泳运行缓冲液包含20mmol/L Na2HPO4-20mmol/L NaH2PO4(pH8.5),20mmol/L十二烷基硫酸钠和体积分数25%甲醇。在18kV电压下5种抗生素在15min内达到基线分离。各组分线性关系良好,检出限5.3～8.1mg/L,进样精密度RSD 3.8%～5.5%。研究表明,对分子结构特别相近的抗生素,通过表面活性剂胶束准固定相与有机添加剂协同作用来改善分离效果是可行的。     

胶束电动色谱在线推扫富集技术测定饮料中的防腐剂苯甲酸

考察了样品预处理、背景缓冲溶液pH、十二烷基硫酸钠（SDS）浓度、进样时间对苯甲酸测定过程中的富集效果的影响。结果显示：在电泳缓冲溶液为20mmol／L硼砂＋60mmol／L十二烷基硫酸钠（pH=9．30），紫外检测波长214nm，分离电压18kV时，富集倍数可达150倍。在线推扫富集胶束电动色谱法减少了样品处理的繁琐过程，操作简单，成本低。大大缩短了分析周期，弥补了毛细管电泳测定微量组分的不足。     

胶束电动色谱在线推扫富集技术测定酱油中的防腐剂苯甲酸含量

建立了在线富集胶束电动色谱法测定酱油中的防腐剂苯甲酸的方法。考察了样品预处理、背景缓冲溶液pH值、SDS浓度、进样时间对苯甲酸富集效果的影响。结果显示:在电泳缓冲溶液为20mmoL/L硼砂+60mmoL/L十二烷基硫酸钠(pH=9.30),紫外检测波长214nm,分离电压18kV时,富集倍数可达150倍以上。减少了样品处理的繁琐过程,操作简单,成本低,大大缩短了分析周期,弥补了毛细管电泳测定微量组分的不足。     

固相萃取-毛细管电泳法测定奶粉中三聚氰胺的含量

建立了高效毛细管电泳法测定奶粉中三聚氰胺含量的方法。在背景电解质溶液为30mmol/L的硼砂缓冲液中加入15mmol/L的十二烷基硫酸钠(SDS),运行电压为15kV,压力进样为10s,柱温为25℃,检测波长为200nm。结果表明:三聚氰胺的线性范围20~50μg/mL(r=0.9994),平均回收率为99.3%,检出限为1μg/mL,定量限为2μg/mL。结论是本法简便快捷,结果准确可靠,可作为该成分的质量控制方法。     

高效毛细管电泳法检测橘皮中橙皮苷的含量

应用毛细管电泳法对橘皮中橙皮苷的含量进行了检测,研究了缓冲液的种类、缓冲液的浓度、缓冲液的pH值以及分离电压等对橙皮苷测定的影响。在pH8.0的150 mmol/L硼砂缓冲液、12 kV分离电压下,橙皮苷的测定效果最佳。毛细管电泳法测定橙皮苷的最低检测限为1.25μg/mL,加样回收率是99.75%,相对标准误差是1.98%。     

胶束电动毛细管色谱法同时测定食品饮料中的四种添加剂

采用胶束电动毛细管色谱法,用50μm×27cm熔融石英毛细管柱,以pH8.0的20mmol/L硼砂 5mmol/LSDS作缓冲溶液,工作电压25kV,检测波长214mm,压力进样1s为分离条件,对5种饮料和1种食品中4种食品添加剂(咖啡因、苯甲酸、山梨酸和糖精)进行了测定同时讨论了工作电压、缓冲液浓度与pH、SDS浓度和内标对测定的影响     

毛细管电泳测定猪肉中克伦特罗的含量

为了建立猪肉中克伦特罗的含量的测定方法,采用高效毛细管电泳法,运行缓冲液为15mmol/L磷酸盐缓冲液(磷酸调pH为6.5);运行电压25kV;柱温25℃;检测波长200nm。克伦特罗线性范围为0.00056～0.01344mg/mL(r=0.9998),加样回收率为99.83%,RSD为1.17%。高效毛细管电泳操作简便、准确,适用于猪肉中克伦特罗的含量的测定     

毛细管电泳法测定发酵液中L-色氨酸的含量

应用高效毛细管电泳法对发酵液中L-色氨酸的含量进行了测定,研究了检测波长、缓冲液pH值、缓冲液浓度、分离电压对L-色氨酸测定的影响。在pH9.5、40 mmol/L硼砂缓冲液、210 nm、25 kV下,L-色氨酸的测定最佳。毛细管电泳仪测定L-色氨酸的检测限为1.389μmol/L,相对标准误差RSD为3.308%,平均加标回收率为101.26%。且高效毛细管电泳法成功用于测定发酵液中的L-色氨酸。预计毛细管电泳法将应用于更广更深的领域。     

蛋白质水解度测定方法综述

对目前国内外常用的蛋白质水解度测定方法进行了综述，其中pH—state方法是通过滴定水解过程中释放的质子测定DH；OPA、TNBS及国内常用的水合茚三酮和甲醛等测定方法是利用游离氨基的反应测定DH。     

SEROLOGIC IDENTIFICATION OF SPECIES OF ORIGIN OF SAUSAGE MEATS

SUMMARY: A partially purified immunoglobulin G (lgG) solution prepared from the serum of species to be tested was heated to the specifications for sausages. The resulting supernatant fluid was decanted and the precipitate washed with saline and used to immunize rabbits. The supernatant fluid was used to sensitize tanned sheep red blood cells. The immune serum was rendered monospecific by absorptions with heterologous, heated lgG precipitates. A sample of monospecific immune serum was absorbed with a washed homogenate of sausage. Aliquots of the monospecific immune serum, both untreated and sausage absorbed, were tested with cells sensitized with the homologous heated lgG supematant fluid. A significant reduction of titer by sausage absorption indicated that the sausages contained the meat homologous to the immune serum.     

BASIS OF STABILITY OF AMINE SALTS OF LINOLEIC ACID

SUMMARY— The mechanism and generality of the known stabilization against autoxidation conferred on linoleic acid by certain basic amino acids, such as lysine and arginine, was investigated. Basic amino acids were the only class of compounds found to confer the effect. However, the smallest basic amino acid, 2,3-diaminopropionic acid, was not effective, nor was αβω-diaminc acid, 3,6-diaminohexanoic acid, although a simple isomer of lysine. The stabilization was observed only in the solid phase. Inclusion of sodium chloride in the solid matrix was deleterious to the effect. A large number of physical and chemical observations were made and correlated but it has not been possible to draw detailed conclusions about the mechanism of stabilization, nor can a detailed structure of the stabilized complex be suggested. The cause of the phenomenon appears to be closely associated with the physical arrangement of the ions in the crystal lattice.     

百年风尚

一场流光溢彩、赏心悦目的展览,一段百年风尚演进的传奇旅程,一次东西方文化艺术的完美对话。2013年9月13日,“博萃臻艺一中西方珍宝艺术展”在辽宁省博物馆举行了隆重的开幕仪式,法兰西共和国驻华大使白林女士、辽宁省文物局局长丁辉先生、辽宁省博物馆馆长马宝杰先生、卡地亚全球总裁兼首席执行官邓阁仕先生、卡地亚区域行政总裁（北亚洲）陆慧全先生、卡地亚中国区首席执行官陆意斯先生、辽宁省文物店总经理张春鹰先生,以及众多文化界与文博界的贵宾齐聚一堂,共同见证了这场文化艺术盛事。     

聚多元羧酸盐的合成及应用

研究了聚多元羧酸盐的合成方法及反应机理,将其应用于洗涤剂和PVC制品中分别代替三聚磷酸钠和邻苯二甲酸二丁酯,证明有良好效果。     

EFFECTS OF TYPES OF FAT AND OF RATES AND TEMPERATURES OF COMMINUTION ON DISPERSION OF LIPIDS IN FRANKFURTERS

ABSTRACT— The effect of time, temperature and rpm of comminution of emulsions was determined on the dispersion of approximately 25% of beef fat, pork fat or cottonseed oil in frankfurters. The numbers of lipid particles 5 μ or less in diameter increased in frankfurters containing either beef or pork fat as comminution was continued to higher temperatures, with pork fat dispersed more thoroughly. Fat tended to separate from frankfurters containing beef fat in particles 200 μ or more in diameter. In contrast, no specific degree of dispersion of particles 5 μ or less in diameter consistently indicated emulsion stability, or its lack. Increased rpm during comminution produced an increased dispersion of beef or pork fat. Under the same conditions pork fat was dispersed more finely than beef fat. Dispersion of cottonseed oil produced finely dispersed particles beyond the resolution of light microscopy, as was confirmed by electron microscopy which showed a substantial number of particles to be less than 1 μ in diameter.     

DEVELOPMENT OF CHAINS OF CELLS OF SACCHAROMYCES CEREVISIAE DURING FERMENTATION

The lengths of chains of cells of Saccharomyces cerevisiae were studied during fermentation. Pitching yeast generally contained about half of the total number of cells as two-celled chains. The chain lengths varied during the subsequent fermentation and the variations were characteristic of the strain. Electronic counting assessments of chain length were unreliable.     

STABILITY OF AQUEOUS EMULSIONS OF THE ESSENTIAL OIL OF HOPS

Hop oil emulsions prepared from different varieties of hops have been found to exhibit enhanced physical stability on the addition of blends of the emulsifiers Span 20/Tween 80 or Span 60/Tween 60. Examination of the particle size and volume distributions of an emulsion by use of a Coulter Counter was found to be an excellent method of monitoring its stability. An indication as to the relative efficiency of emulsifiers can be obtained from Coulter Counter measurements on hop oil emulsions after storage for 4 days. The use of an ultracentrifuge provies a rapid means of testing emulsion stability and hence the effectiveness of emulsion stabilizers.     

矩阵乘积的行式,列式

给出了ｍ×ｍ矩阵与ｍ×ｎ矩阵的行（列）式的表达式．若Ａ＝ａ１１ａ１２…ａ１ｍａ２１ａ２２…ａ２ｍ……ａｍ１ａｍ２…ａｍｍＢ＝ｂ１１ｂ１２…ｂ１ｎｂ２１ｂ２２…ｂ２ｎ……ｂｍ１ｂｍ２…ｂｍｎ分别是ｍ×ｍ，ｍ×ｎ矩阵，则｜Ａ｜｜Ｂ｜＝｜ＡＢ｜＋∑ｉ１＜ｉ２＜…＜ｉｔｊ１＜ｊ２＜…＜ｊｔ１≤ｔ≤ｍｎ－ｔ≥ｍＮＢｉ１ｉ２…ｉｔｊ１ｊ２…ｊｔＮＡＢ１…ｍ（－１）ｓｔ＋１ｊｔ＋１…（－１）ｓｎｊｎ其中ｉ１，ｉ２，…，ｉｔ是１，２，…，ｍ中ｔ个数码；ｊ１，ｊ２，…，ｊｔ，ｊｔ＋１，…，ｊｎ是１，２，…，ｎ的一个排列；ｓｒ＝π（ｊ１，ｊ２，…，ｊｔ，ｊｒ）（ｒ＝１，２，…，ｎ）是排列ｊ１，ｊ２，…，ｊｔ，ｊｒ的反序数．     

ANALYTICAL CHARACTERIZATION OF THE PRODUCTS OF NONENZYMATIC GLYCOSYLATION OF LYSOZYME

The quantitative analysis of the reaction products of the water activity dependent nonenzymatic glycosylation of lysozyme was not straightforward. Difficulties arose in the determination of the number of bound glucose molecules because glycosylation leads to glucose mediated protein aggregation, and the likely presence of a mixture of relatively labile Schiff-base intermediates, and the more stable ketoamine products generated by Amadori rearrangement. Polyacrylamide gel electrophoresis was used to monitor protein aggregation; periodate oxidation, nuclear magnetic resonance (NMR), and oxalic acid hydrolysis combined with HPLC, emerged as the most promising methods to quantitate the degree of glycosylation. Possible interpretations are advanced to explain the apparent discrepancies in degree of glycosylation suggested by the different analytical methods evaluated.