芹菜中营养素的实验探究

采用常规的研磨、脱色、过滤方法对芹菜做预处理。利用常用仪器、微型实验,对芹菜中所含营养素进行定性检测。实验结果表明：芹菜中含有蛋白质、维生素、铁、镁、钙、磷、草酸。此外,芹菜叶中还含有钾,在此实验条件下不能确定芹菜茎中是否含有钾。芹菜叶中含有的营养素远大于芹菜茎,在食用芹菜时不应将芹菜叶丢掉,应利用化学知识来提高生活质量。     

菠菜、葱与豆腐可否一起吃的实验探究

通过探究菠菜、葱与豆腐是否可以一起吃,使学生深刻理解化学与生活的密切联系。分别检验菠菜、葱中的钙、铁、镁和草酸;检验豆腐中的钙、铁、镁;菠菜与葱中草酸能否与豆腐中的钙生成不溶性草酸钙。     

高师生分组探究木耳中铁、碘与钙的实验设计

为了让高师生体验探究学习,掌握探究方法、发展实验设计和探究能力,探索用适宜浓度盐酸溶液浸泡木耳,取其浸泡液与饱和硫氰酸钾溶液反应,检验木耳中的铁;取其浸泡液加入淀粉溶液后与适量碘盐反应,检验木耳中的碘;取其浸泡液分别加入饱和草酸铵溶液、饱和碳酸钠溶液、20%氢氧化钠溶液,检验木耳中的钙。     

用碳酸饮料验证二氧化碳性质的教学设计

为了使学生深刻理解化学与生活的密切关系,通过用碳酸饮料收集二氧化碳来验证二氧化碳的性质。二氧化碳能使新制的澄清石灰水变浑浊,二氧化碳不支持燃烧,二氧化碳在水中的溶解度随温度的上升而减小,二氧化碳能使蘸有石蕊的棉球与湿润的蓝色石蕊试纸变为红色。     

Mn(V)的定性检验及试管实验的条件优化

探讨了在实验室制备MnO43-的反应条件,并利用紫外可见吸收光谱定性检验了制备的MnO43-离子,同时提出了一个在试管实验里迅速制备和检验MnO43-的方法.本实验可用于大学普通化学实验教学中,帮助学生更加直观地认识Mn(V).     

Mn(Ⅴ)的定性检验及试管实验的条件优化

探讨了在实验室制备MnO34-的反应条件,并利用紫外可见吸收光谱定性检验了制备的MnO34-离子,同时提出了一个在试管实验里迅速制备和检验MnO34-的方法。本实验可用于大学普通化学实验教学中,帮助学生更加直观地认识Mn(Ⅴ)。     

有机物化学检验法的分析、讨论与应用

随着仪器分析的发展和广泛应用,针对有机化合物的化学鉴别方法研究近年来逐渐淡出化学学科前沿。然而化学鉴别方法由于其广泛的实用性和较低的成本,仍在有机定性与定量分析中占有一席之地。从典型有机物的化学鉴定分析方法入手,根据机理分类阐述了各类有机物的化学检验,并详细地讨论了几种机理较为复杂或易存在认识误区的化学检验手段,如茚三酮定性定量测试、双缩脲定性定量测试、Fehling与Benedict定性测试等。     

基于科学风险认知的九年级“营养与化学”复习课设计

基于科学风险认知角度创新设计“营养与化学”的中考复习课,尝试以食品营养相关的社会性科学议题和网络传播的伪科学信息为载体,引领学生运用基础知识加以分析、评价和批判,达到综合应用知识体系和培养科学风险决策能力的目的。     

标准加入法数据处理的改进及用于测定宜昌茶叶的氟含量

利用氟离子选择电极,采用一种改进的标准加入法的数据处理方法测定湖北宜昌几种茶叶中的氟含量.与传统的标准加入法不同的是:以加入标准溶液后测得溶液中待测物质(如:氟离子)的总质量(样品及加入标准液后氟离子的质量之和)对加入标准液的中该物质的质量(标准液中氟离子的质量)作图.湖北宜昌某品牌茶叶中的氟含量为46.8±0.5 mg/kg,相对标准偏差(RSD)为0.79%,加标回收率在98.0%～102.5%之间.改进后的标准加入法的数据处理方法简单、快速,能够提供更多的信息(如:加标回收率).     

碘的升华及性质检验微型实验探究

对碘的升华及性质检验进行微型一体化的实验,操作简单,现象明显,试剂用量少,克服了现行高中化学课本中碘升华实验的弊端,同时实现其性质的检验,符合定性实验的要求,有利于提高教学效果及普及学生单人实验.     

Phenolic,Carotenoid and Saccharide Compositions of Vietnamese Camellia sinensis Teas and Herbal Teas

Tea (Camellia sinensis) and herbal tea have been recognized as rich sources of bioactive constituents with the ability to exert antioxidant actions. The aims of this study were to analyze phenolic, carotenoid and saccharide contents in a set of Vietnamese tea and herbal tea and compare the results with those of green and black teas marketed in the U.S. In total, 27 phenolics, six carotenoids and chlorophylls, and three saccharides were quantitatively identified. Catechins, quercetin glycosides and chlorogenic acid were the predominating phenolics in the teas, with the concentrations following the order: jasmine/green teas > oolong tea > black tea. Lutein was the dominant carotenoid in the teas and its concentrations were generally found to be higher in the jasmine and green teas than in the oolong and black teas. The study showed that the green teas originating in Vietnam had much higher levels of phenolics and carotenoids than their counterparts stemming from another country. The application of partial least squares discriminant analysis (PLS-DA) as a chemometric tool was able to differentiate phenolic profiles between methanolic extracts and tea infusions. Through principal component analysis (PCA), the similarities and dissimilarities among the jasmine, green, oolong, black teas and herbal teas were depicted.     

应用手持微型激光荧光光谱仪测定常见蔬果中的花青素

采用手持微型激光荧光光谱仪对几种常见蔬果中是否含有花青素进行了定性检测。实验结果表明,采用405 nm小功率激光可以有效地激发花青素荧光,并能显示出比410 nm激光更显著的光谱特征,能方便、有效地在任何日常环境下实施对花青素的鉴定。所测结果与文献相吻合：桑葚、黑加仑和草莓中含花青素,而番茄、大蒜中不含。本实验操作简单,安全可靠、灵敏度高,可以作为演示实验和学生综合探究实验。     

高效液相色谱多波长定性方法研究

介绍了高效液相色谱法中除常用的保留时间和光谱图定性以外的另一方法──多波长定性分析方法。根据Beer's定律可知,同一化合物在不同波长下测得的峰面积之比为定值。利用高效波相色谱多波长同时检测的方法,比较化合物在不同波长下的峰面积大小,建立了简便的定性方法,并在禁用假氮染料测定时对18种芳香腔的定性分析中得到成功的应用。     

常见茶叶中14种元素含量分析及重金属风险评价

采集传统名茶地标产品样品各3种为实验样品,通过ICP-OES和ICP-MS对样品进行K、Ca、Mg、Mn、B、Cu、Fe、Ni、Zn、Cr、Co、Cd、As、Pb等14种元素的含量测定.利用单因素方差分析、主成分分析、污染评价等方法,对茶叶无机元素含量进行分析和污染评价,并对污染来源进行了研究.结果表明,不同产地茶叶样...     

富钙、锌、铜、铁营养元素莲子生产方法

通过田间中区莲子栽培实验及分析表明,加施高技术产品多元络合微量植物营养素,显著增加了莲子的营养元素含量。其钙、锌、铜,铁含量分别比普通莲子高２３．８％、９２．９％、１０９．１％、９．３％,而这几种元素正是目前儿童、孕犋 最缺乏的营养元素,该产品的问世为儿童孕妇、老年人带来福音。     

火焰原子吸收法测定茶叶中的微量元素

使用同一消化液,溶解消化样品,以稀盐酸为底液,火焰原子吸收分光光度法对茶叶中Mn、Fe、Zn、Cu、Pb五种微量元素进行了测定。结果表明,标准曲线线性关系良好(r＞0．999)、精密度和准确度均较好,能够达到分析要求。     

Detection of Ovine or Bovine Milk Components in Commercial Camel Milk Powder Using a PCR-Based Method

Food ingredient adulteration, especially the adulteration of milk and dairy products, is one of the important issues of food safety. The large price difference between camel milk powder, ovine, and bovine milk powder may be an incentive for the incorporation of ovine and bovine derived foods in camel milk products. This study evaluated the use of ordinary PCR and real-time PCR for the detection of camel milk powder adulteration based on the presence of ovine and bovine milk components. DNA was extracted from camel, ovine, and bovine milk powder using a deep-processed product column DNA extraction kit. The quality of the extracted DNA was detected by amplifying the target sequence from the mitochondrial Cytb gene, and the extracted DNA was used for the identification of milk powder based on PCR analysis. In addition, PCR-based methods (both ordinary PCR and real-time PCR) were used to detect laboratory adulteration models of milk powder using primers targeting mitochondrial genes. The results show that the ordinary PCR method had better sensitivity and could qualitatively detect ovine and bovine milk components in the range of 1% to 100% in camel milk powder. The commercial camel milk powder was used to verify the practicability of this method. The real-time PCR normalization system has a good exponential correlation (R² = 0.9822 and 0.9923) between ovine or bovine content and Ct ratio (specific/internal reference gene) and allows for the quantitative determination of ovine or bovine milk contents in adulterated camel milk powder samples. Accuracy was effectively validated using simulated adulterated samples, with recoveries ranging from 80% to 110% with a coefficient of variation of less than 7%, exhibiting sufficient parameters of trueness. The ordinary PCR qualitative detection and real-time PCR quantitative detection method established in this study proved to be a specific, sensitive, and effective technology, which is expected to be used for market detection.     

定性检验牛奶中的营养素

利用常用仪器、微型实验和相应物质的特征反应,对牛奶中所含营养素进行定性检验,结果表明：牛奶中含有蛋白质、维生素、钙、镁、磷、钾、铁元素。该实验具有微型化、绿色化、简约化和生活化的特质。     

方法检出限三个评估方法标准解读与比较

文献中有多项方法检出限评估标准,如何正确理解和运用这些标准得到可比较的参数对基层实验室具有指导意义。对目前国内外方法检出限评估方法标准进行了系统总结和梳理,介绍了不同方法的特点、适用范围和注意事项。利用实验室实例和文献数据,比较了三种代表性方法计算结果。基于科学性和可操作性的原则,针对不同需求,提出了检出限评估改进建议及实施方案。     

Design and Applications of Small Molecular Probes for Calcium Detection

The physiological significance of calcium ions such as the role in cellular signalling, cell growth, etc. have driven the development of methods to detect and monitor the level of Ca²⁺ ions, both in vivo and in vitro. Although various approaches for the detection of calcium ions have been reported, methods based on small molecular fluorescent probes have unique advantages including small probe size, easy monitoring of detection processes and applicability in biological systems. In this review article, we will discuss the progress in the development of Ca²⁺‐binding fluorescent probes by taking into account the types of chelating groups that have been employed for Ca²⁺ binding.