共查询到18条相似文献，搜索用时 218 毫秒
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HPLC内标标准曲线法测定茶叶中4种儿茶素和咖啡因 总被引：1，自引：0，他引：1
选用葛根素作为内标物质,利用内标标准曲线法建立高效液相色谱同时测定茶叶中（-）表没食子儿茶素（EGC）,（-）表没食子儿茶素没食子酸酯（EGCG）,（-）表儿茶素（EC）,（-）表儿茶素没食子酸酯（ECG）,咖啡因（CAF）5种组分的分析方法.采用C18柱,甲醇和0.05%三氟乙酸水溶液为流动相,梯度洗脱,DAD检测器,检测波长278 nm.结果表明,各组分的色谱峰均达到基线分离,该方法重复性好,灵敏度高,回收率高,已用于不同种类26个茶叶样品的测定.以这5种活性成分为指标,采用聚类分析法可对不同来源的样品进行统计分析. 相似文献
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以 HPLC-ESI-MS ／TOF 为研究手段,应用正交实验、直观分析和方差分析等方法对仪器参数进行优化,并以茶叶中的茶多酚为研究对象,建立了大叶茶中 EGC,EC,EGCG 和 ECG 这4种儿茶素组分的质量分数质谱测定方法。结果表明,该方法可在6 min 内实现单个样品中茶多酚质量分数的快速定量,且方法简单、快速、灵敏度高、线性范围宽等,可用于茶叶中茶多酚质量分数的快速定量。 相似文献
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建立一种用高效液相色谱法测定茶叶中儿茶素的含量.方法:样品经乙醇提取,超声30min后,过C18小柱净化,样品溶液经0.45μm滤膜过滤后,用于HPLC分析.使用C18(5 um,150 mm×6.0 mm)色谱柱进行分离,用不同体积比混合的流动相A及流动相B的混合液作梯度淋洗,流速为1.0 ml/min,检测波长为280 nm,柱温为40℃.以甲醇∶水∶乙酸-26∶73.5∶0.5(体积比)为流动相.儿茶素在0.02～0.3 g/L范围内线性关系良好,回收率在98.2%～100.3%之间,相对标准偏差为1.6643%.该方法具有操作简便、快速、精密度高、回收率好、重现性较好、检测限低等优点. 相似文献
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气相色谱法测定奶粉中香兰素的含量 总被引：2，自引：0，他引：2
建立了氢火焰离子化检测器一气相色谱法(FID-GC)检测奶粉中香兰素含量的方法.考察了不同萃取剂对样品预处理的影响,同时对色谱分离条件如毛细管柱极性、柱温及载气流速等条件进行了优化,目标峰获得良好分离.标准曲线方程为y=8539099x-2189,R=0.9995,方法检出限0.003mg.g-1;加标回收率介于93.8%～99.4%之间.RSD=2.5%(n=5).所建立的方法用于实际样品测定获得满意结果. 相似文献
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利用毛细管电泳法对苹果中阿魏酸和儿茶素做了定性定量分析.通过分离条件的优化,确定了分离苹果中阿魏酸和儿茶素的最佳缓冲液为30 mmol/L硼砂-硼酸+30％乙腈+50 mmol/L SDS,pH=8,这两种酚类物质在10 min内能较好地得到分离.得到儿茶素的峰面积和迁移时间的相对标准偏差(RSD)分别为2.39％和2.92％,阿魏酸的峰面积和迁移时间的RSD分别为3.41％和5.12％;儿茶素的回收率在90％～102％之间,阿魏酸的回收率在87％～105％之间.该方法简单、准确,可作为苹果果实品质测定的一种优良方法. 相似文献
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建立党参中18种农药残留量的分析方法,对10种不同批次的党参样品进行农药残留测定.样品以乙腈-水(5+1)涡旋震荡萃取,提取液经Carb/NH2固相萃取柱(SPE)净化后、再经在线凝胶渗透色谱(gel permeation chromatography,GPC)净化,利用气相色谱-质谱选择离子监测模式进行分析,外标法定量.18种农药峰面积与质量浓度在10～ 1000 μg·L-1呈良好线性关系,相关系数为0.993～1.000;定量限(10S/N)在0.06～6.3μg·kg-1;在20～200 μg·kg-13个浓度水平下,方法回收率为76.8％-104.4％,RSD为4.2％～9.9％.该方法简便、快速,灵敏度高、重复性好,能够准确地检测党参中18种农药残留. 相似文献
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本文建立了高效液相色谱法测定饮料中塑化剂组分之一--邻苯二甲酸二辛酯的分析方法.饮料样品只需要进行简单的前处理后即可进样.实验的色谱条件：柱温30℃,流动相为甲醇,流速1 mL/min,检测波长280 nm.建立的方法在0.1935～2.9031 mg/L范围内具有良好的线性关系（r=0.9999）,方法的检出限（LOD）为1.15 μg/L;应用该方法测定饮料中的邻苯二甲酸二辛酯,实际样品的加标回收率在97.43～103.85％范围;相对标准偏差（RSD％）低于0.28％.结果表明,该方法操作简单、快速、准确,用于饮料中塑化剂组分中邻苯二甲酸二辛酯的分析结果满意. 相似文献
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采用超声波提取茶叶中的茶多酚,并应用高效液相色谱法对不同品种的茶叶及同一产地不同档次的茶叶中的茶多酚成份进行分析测定.结果表明,采用Hyper-sil ODS柱,超纯水、甲醇和0.36%的乙酸为流动相,梯度洗脱,流速为0.8 mL.min-1,柱温40℃,在280 nm波长处可对儿茶素进行检测,其线性范围为0.6~3.0 g.L-1,R为0.999 6~0.999 9. 相似文献
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对茶寄生中茶多酚的含量进行分析．茶多酚是混合物,由于各种茶多酚结构相似,较难分离．没食子酸（EC）、表没食子儿茶素（EGC）、没食子儿茶素没食子酸酯（EGCG）、表儿茶素没食子酸酯（ECG）4种茶多酚是茶叶中茶多酚的主要成分．本研究采用高效液相色谱（ HPLC）法同时测定了EC、EGC、EGCG、ECG 4种茶多酚,4种茶多酚在15 min内达到有效分离,方法的变异系数小于0．0360％,回收率为95．2％～104．2％．实验结果表明,茶寄生样品中只含有茶多酚中的EGC,其中云南粗茎茶寄生样品中的EGC含量略高于云南细茎茶寄生样品中EGC含量． 相似文献
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Dong-mei Fan Kai Fan Cui-ping Yu Ya-ting Lu Xiao-chang Wang 《Journal of Zhejiang University. Science. B》2017,18(2):99-108
Polyphenols are one of the most important secondary metabolites, and affect the decomposition of litter and soil organic matter. This study aims to monitor the mass loss rate of tea leaf litter and nutrient release pattern, and investigate the role of tea polyphenols played in this process. High-performance liquid chromatography (HPLC) and classical litter bag method were used to simulate the decomposition process of tea leaf litter and track the changes occurring in major polyphenols over eight months. The release patterns of nitrogen, potassium, calcium, and magnesium were also determined. The decomposition pattern of tea leaf litter could be described by a two-phase decomposition model, and the polyphenol/N ratio effectively regulated the degradation process. Most of the catechins decreased dramatically within two months; gallic acid (GA), catechin gallate (CG), and gallocatechin (GC) were faintly detected, while others were outside the detection limits by the end of the experiment. These results demonstrated that tea polyphenols transformed quickly and catechins had an effect on the individual conversion rate. The nutrient release pattern was different from other plants which might be due to the existence of tea polyphenols. 相似文献
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Le Ying De-dong Kong Yuan-yuan Gao Feng Yan Yue-fei Wang Ping Xu 《Journal of Zhejiang University. Science. B》2018,19(3):199-210
Phenolics, as the main bioactive compounds in tea, have been suggested to have potential in the prevention of various human diseases. However, little is known about phenolics and their bioactivity in Zhangping Narcissue tea cake which is considered the most special kind of oolong tea. To unveil its bioactivity, three phenolic-enriched extracts were obtained from Zhangping Narcissue tea cake using ethyl acetate, n-butanol, and water. Their main chemical compositions and in vitro bioactivity were analyzed by high-performance liquid chromatography (HPLC) and ultraperformance liquid chromatography-mass spectrometry (UPLC-MS). The ethyl acetate fraction (ZEF) consisted of higher content of phenolics, flavonoids, procyanidins, and catechin monomers (including epigallocatechin gallate (EGCG), epicatechin gallate (ECG), and gallocatechin gallate (GCG)) than n-butanol fraction (ZBF) and water fraction (ZWF). ZEF exhibited the strongest antioxidant capacity in vitro due to its abundant bioactive compounds. This was validated by Pearson correlation and hierarchical clustering analyses. ZEF also showed a remarkable inhibition on the growth, migration, and invasion of 4T1 murine breast cancer cells. 相似文献
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李海生 《广东教育学院学报》2005,25(3):74-76
通过水培方法,就环境中不同铜离子水平下茶苗对铜的吸收与累积进行了研究.结果表明:茶苗根、茎中铜含量均随着铜处理浓度的增加而明显增加,而叶中含量影响不大.各处理下铜在茶苗各部位含铜量大小依次为根>茎>叶.从整株植物来看,随着铜处理浓度的增加,铜在根部的积累量增加,在茎和叶的积累量趋于下降.适量的铜有助于茶苗根、茎、叶对磷的吸收,但超过一定限度,则茶苗含磷量下降. 相似文献
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用高效液相色谱仪（HPLC）分析普洱生茶、熟茶与红茶的主要化学成分含量（质量分数）.结果表明：普洱生茶、熟茶及红茶在278 nm处具有截然不同的色谱图及化学成分.普洱生茶保留了较多的ECG,EGCG以及C等多酚类物质;红茶因其酶促作用形成了一系列的氧化产物—茶黄素类和茶红素类,也保留了一定量的未氧化的多酚类物质;而普洱熟茶的湿热作用却只形成一定量的TR,未氧化多酚类物质的含量（质量分数）也较低,ECG和EGCG几乎完全氧化,且氧化产物中不含茶黄素类. 相似文献
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明清时期是北京古代休闲文化发展的鼎盛时期。外城西区是北京茶馆最主要的分布区,茶馆数目占到了全城茶馆资源六成多的比重,其他城区和郊区只有少量分布。北京茶馆的分布明显有倾向于市场区的特点。茶馆林立的香厂在清末发展成为一处新兴的休闲型市场娱乐区。 相似文献
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It is important to research the rules about accumulation and distribution of arsenic and cadmium by tea plants, which will give us some scientific ideas about how to control the contents of arsenic and cadmium in tea. In this study, by field inves- tigation and pot trial, we found that mobility of arsenic and cadmium in tea plants was low. Most arsenic and cadmium absorbed were fixed in feeding roots and only small amount was transported to the above-ground parts. Distribution of arsenic and cadmium, based on their concentrations of unit dry matter, in tea plants grown on un-contaminated soil was in the order: feeding roots>stems≈main roots>old leaves>young leaves. When tea plants were grown on polluted soils simulated by adding salts of these two metals, feeding roots possibly acted as a buffer and defense, and arsenic and cadmium were transported less to the above- ground parts. The concentration of cadmium in soil significantly and negatively correlated with chlorophyll content, photosyn- thetic rate, transpiration rate and biomass production of tea plants. 相似文献