鱼体中两种挥发性有机残留物的提取与检测

目的 研究水蒸汽蒸馏方法提取鱼体中挥发酚和硝基苯的效果, 并研究鱼体中挥发酚和硝基苯残留量的测定方法。方法 用自制水蒸汽发生器蒸馏提取挥发酚和硝基苯, 并测定两种物质含量。结果 水蒸汽发生器蒸馏法泡沫产生少, 蒸馏过程稳定、容易控制, 不存在暴沸现象。鱼体中挥发酚测定平均回收率在85.5%以上, 硝基苯测定平均回收率为96.83%。硝基苯出峰时间为10.051 min, 分离度高, 检测时间短、消耗有机溶剂量少、试验简便, 完全能够满足检测分析的需要。 结论 水蒸汽蒸馏提取法效果好, 方法实用, 便于操作, 适用于处理后样品的分析测定, 已应用于鱼体中挥发酚和硝基苯残留量的测定。     

欧洲鲇（Silirus Glanis L.）胃黏膜蛋白酶

水解蛋白质的酶在工业上有广泛的用途.食品工业中,蛋白水解酶用于肉的软化和奶酪制作;农业领域中,蛋白水解酶被加到饲料中以增加喂养效率;医学上对这些酶的应用包括酶诊断和酶治疗(尤其是在外科手术中,如治疗烧伤);蛋白质化学的研究中,蛋白水解酶作为工具广泛用于研究蛋白质和多肽的一级结构.另外,蛋白酶是研究酶活性位点结构、活性调节,解决其他酶学和分子生物学重要问题的理想对象.因此,寻找高活性蛋白酶的新来源仍是一个重要的课题.     

原子荧光光谱法测定水产品中硒含量

采用微波消解的样品预处理技术和氢化物发生-原子荧光法,测定了水产品中硒含量.通过试验,确定了微波消解样品的条件,优化了仪器的最佳工作参数,并对样品中6价硒的还原方式方法进行了研究和探讨.试验中硒的检出限0.06μg/L,标准曲线最佳线性范围0.5μg/L～20μg/L,加标回收率95.3%～104.5%,相对标准偏差(RSD)为1.8%～5.0%(n=5).方法简便快速、结果准确、灵敏度高、仪器廉价,易于普及,适用于水产品中硒的快速检测.     

Separation and purification of proteinases from Gastric Mucosa of Northern Sheatfish,Silurus soldatovi

The separation and purification method for pepsin of Northern Sheatfish (Silurus soldatovi) was established by using the combination technology of salting-out,gel chromatography and gel electrophoresis,and the enzymic properties were also analyzed.The experimental results indicated that 28% and 56% (NH4)2SO4 saturation could separate the activated protease from the pepsin extract of gastric mucosa of Sheatfish (Silurus soldatovi) ;compared with the homogenate extraction,the pepsin specific activity of purified extraction by Sephadex G-75 gel chromatography system increased 598 fold,was 5 times higher than that of activated liquid,and the total production rate was 10.1%.The purified pepsin liquor at the conditions of pH3.3 0.01 M alanine-formic acid buffering solution,60 cm chromatography column,and the flowing rate of 0.8 ML/min was analyzed by SDS-PAGE,which indicated that there were two bands and the molecular weight was 34.0 kDa and 40.4 kDa,respectively.There were two peaks in the enzyme activity determination of the separated collecting liquor in gel chromatography,and the SDS-PAGE showed the concentrations of the two proteins was different,which indicated that it existed at least two pepsins in the gastric mucosa of Sheatfish (Silurus soldatovi).