排序方式: 共有41条查询结果,搜索用时 15 毫秒
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研究了以5-Br-PADAP为显色剂,采用流动注射pH梯度技术分光光度同时测定人发中锌铜含量及直接测定锌铜比值的新方法.该方法分析频率达到20~30次/h,测定锌、铜的线性范围分别为0.2~5.0μg/mL和0.1~2.0μg/ML.方法简便快速,准确可靠,且具有良好的重现性,用于实际样品的测定,结果满意. 相似文献
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食品中甜味剂的检测方法 总被引:2,自引:0,他引:2
文章引用文献一百多篇,比较详细地对近年来食品中甜味剂检测中应用的各种技术方法进行了总结。 相似文献
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柚皮苷的溶剂热法提取及其抗氧化性、稳定性测定 总被引:1,自引:0,他引:1
对柚皮中柚皮苷进行提取,并测定其抗氧化和稳定性。以乙醇-水混合体系为溶剂,对恩施特产贡水白柚皮中柚皮苷进行溶剂热法提取,提取的柚皮苷用紫外吸收光谱定量测定。考察乙醇体积分数、柚皮粉粒度、填充度、提取温度及提取时间对柚皮苷提取率的影响。方法的回收率为96.51%~101.9%,相对标准偏差小于0.16%。同时,采用流动注射化学发光分析测定了柚皮苷的抗氧化性能,并通过测定不同放置时间条件下样品溶液的紫外吸收光谱强度对柚皮苷的稳定性进行测定。结果表明,该溶剂热法提取柚皮苷效率较高,提取最佳工艺条件为乙醇体积分数70%、柚皮粉粒度120目、填充度80%、提取温度60℃和提取时间3h。提取出的柚皮苷具有较强的抗氧化性能和一定的稳定性。 相似文献
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Masayuki Izawa Masachika Takashio Teruo Tamaki 《Journal of the Institute of Brewing》1996,102(3):183-189
To eliminate the influence of maltose, ethanol, low molecular weight β-glucan and an inhibitor of the calcofluor fluorescence reaction in wort and beer on the measured values of a calcofluor-FIA, a post-column calcofluor-FIA method has been developed using a short-size gel permeation chromatography column (6.0 × 50 mm). A column packed with polyhydroxymethacrylate gel (molecular weight exclusion limit, 100,000) was found to be the most appropriate for this system. This short column allowed rapid and specific measurement of high molecular weight β-glucan in a few minutes without the influence of the fluorescence inhibitor, maltose and ethanol which have molecular weights of less than 1000 daltons. Because the low molecular weight β-glucan responsible for the scatter caused by a slight difference in measuring conditions such as temperature, calcofluor concentrations, sample volumes, etc., was separated through the use of the column, the measured values by the post-column calcofluor-FIA method hardly fluctuated under different conditions. Though it has been recognized that dilution of a sample could affect a calcofluor FIA, the new system was not influenced. This also made it possible to measure the β-glucan content in dark-coloured samples (even over 100 EBC colour units). The measured values by the post-column FIA showed a high correlation (r2 = 0.993) with those obtained by the enzymatic method (the McCleary method). 相似文献
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混旭 《青岛科技大学学报(自然科学版)》2010,31(1):6-8
基于在NaOH介质中,铁氰化钾直接氧化焦酚产生化学发光这一现象,建立了一种流动注射化学发光测定焦酚的新方法。该方法测定焦酚的线性范围为0.01~3.8μg.mL-1,检出限为0.008μg.mL-1,相对标准偏差为2.7%(n=7,c=0.2μg.mL-1)。 相似文献