原子吸收光谱法连续测定茶叶多种微量元素

正茶叶在生长过程中易吸收土壤中的金属元素而含有多种矿质元素,其中以磷和钾含量最高,其次为钙、镁、铁、锰、铝,微量成分有铜、锌、钠、硫、氟、硒等。这些矿质元素中的大多数对人体健康是有益的,茶叶的品质与这些元素的缺乏或超量有着密切关系。因此要掌握茶叶中各成分的含量,科学地指导茶园的施肥,首先要检测茶叶中的微量金属元素的含量,原子吸收光谱法     

奶粉中钾含量的不确定度研究

本文主要依据GB5413.21-2010《食品安全国家标准-婴幼儿食品和乳品中钙、铁、锌、钠、钾、镁、铜和锰的测定》,用火焰原子吸收法测定奶粉中钾的含量,进行不确定度的评定.     

京西稻糙米及精米中9种微量矿物质元素含量对比分析

目的 比较京西稻糙米和精米中9种微量矿物质元素的含量差异。方法 20份京西稻稻谷样品脱壳而成的糙米和进一步加工得到的精米经微波消解法前处理后, 由电感耦合等离子体发射光谱法测定样品中钙、铜、铁、钾、镁、锰、钠、磷、锌9种微量矿物质元素的含量, 并对数据进行分析。结果 分析20份样品各元素的平均含量, 糙米中的镁、磷、钾、锰、钙、钠、铁、锌、铜元素含量分别的是精米的174.5%、147.1%、143.0%、138.2%、115.7%、113.2%、106.7%、96.6%、95.8%。结论 京西稻糙米中镁、磷、钾、锰的含量远高于精米, 糙米中钙、钠、铁的含量略高于精米, 而糙米中锌和铜的含量略低于精米。     

四川会理烟区烤烟矿质元素含量与评吸结果的关系分析

对四川会理烟区烤烟中的11种矿质元素（氮、磷、钾、钙、镁、铁、锰、硼、锌、铜、氯）含量及其与香气质、香气量和评吸总分的关系进行了分析。结果表明: (1)会理烟区烟叶中磷、钙、硼、铁、锰、锌、氯的含量在较适宜的范围内,但烟叶中氮、钾含量较低,镁、铜含量缺乏;(2)偏相关分析表明,香气量得分与氯的含量显著负相关,评吸总分分别与氯和钾的含量显著负相关和正相关,但香气质得分与分析的11种矿质元素关系不显著;（3）通径分析表明,镁和钾的含量对烟叶香气质得分、香气量得分和评吸总分有较大的正面影响,铁和氯的含量对烟叶香气质得分、香气量得分和评吸总分有较大的负面影响。      

利用ICP光谱仪测定茶叶中十二种元素的研究

试验研究了ICP测定茶叶中钾、钠、钙、镁等十二种元素的方法,结果表明,所建立的方法准确度和精密度较高,完全能满足茶叶测定的要求。因此,利用该方法测定了不同茶叶中十二种元素的含量,并对其特征进行了初步分析。     

茶叶水中重金属铅、铜、锌、锰的浸出率试验研究

以毛尖、普洱茶叶为研究对象,模拟实际生活中泡茶方式,考察了浸泡次数、浸泡时间、浸泡水温3种不同浸泡方式对铜、锌、锰金属元素浸出率的影响,采用火焰原子吸收光谱法检测茶叶中的重金属含量。结果表明:2种茶叶中Pb含量很小,低于检出限,Cu、Zn、Mn的含量未超标,但是Mn含量高,毛尖、普洱茶叶Mn含量分别为696.0mg/kg和659.4mg/kg;浸泡时间为30min、浸泡水温为90℃时,第一次浸泡的茶水中铜、锌、锰的浸出率最高。     

电感耦合等离子体质谱法同时测定马鹿皮中9种元素

目的建立微波消解-电感耦合等离子体质谱(inductively coupled plasma mass spectrometry,ICP-MS)法同时测定马鹿皮中钠、锰、镁、钾、钙、铁、硒、铜和锌9种元素的含量的方法。方法样品经硝酸-过氧化氢微波消解后,通过在线加入内标溶液校正,以72Ge为内标,采用ICP-MS测定马鹿皮中钠、锰、镁、钾、钙、铁、硒、铜和锌9种元素的含量。结果 9种元素线性良好,相关系数为0.9995~1.0000;钠、锰、镁、钾、钙、铁、硒、铜和锌的检出限分别为4、0.007、0.2、1、1、0.3、0.004、0.009、0.05 mg/kg;9种元素的回收率在86%~116%之间;相对标准偏差(relative standard deviation,RSD)≤7.2%(n=6)。结论该方法灵敏度高、稳定性好,可以满足马鹿皮中钠、锰、镁、钾、钙、铁、硒、铜和锌的测定。     

浙江省炒制香榧中9种矿物元素含量的研究

采集浙江省41个品牌炒制香榧样品,测定钾、镁、钙、铁、锰、锌、铜、硒和钠9种矿物元素含量,分析矿质元素含量的分布频率及区域差异。结果表明,香榧中9种矿物元素分别为钾12 639 mg/kg、镁5 047 mg/kg、钠2 532 mg/kg、钙2 119 mg/kg、锌117 mg/kg、铜67.0 mg/kg、铁61.9 mg/kg、锰35.6 mg/kg、硒0.224 mg/kg。浙江省炒制香榧钾含量高于一般干果,宁波地区硒含量显著高于绍兴、金华地区,部分香榧达到富硒产品标准。浙江省香榧中锌含量变异系数为179%,达极显著变异水平,诸暨市和磐安县香榧中锌含量远高于其他县,绍兴地区香榧中钾、锌、钙、镁显著高于金华等地区。     

五味子及其发酵品中微量元素含量的测定

采用空气-乙炔原子吸收法测定五味子、五味子酒以及五味子发酵果渣中微量元素的含量。用微波消解法对样品进行前处理,各元素标准溶液逐级稀释,测定标准系列的吸光度值,绘制标准曲线。结果表明:对于所测元素,标准曲线回归方程相关系数R20.997 3;测得五味子及其发酵品中钾、钙、钠、镁、铁、锌、锰、铜8种微量元素,其中钾、镁、钙、钠、锰元素含量较高,铁、铜、锌元素含量相对较低。所得数据为五味子药材及其发酵品的进一步研究及开发提供了数据参考及支持。     

火焰原子吸收法测定马齿苋中10种无机元素

目的测定马齿苋中无机元素含量,为其药效学研究及食用开发提供资料。方法利用火焰原子吸收光谱法测定马齿苋中钾、钙、钠、镁、铜、锌、铁、锰、铬、镍的含量。结果马齿苋所含10种无机元素中,钾、钙、镁为宏量元素,其余7种为微量元素。结论本研究为马齿苋的后续研究及进一步开发应用提供数据支持。     

基于矿质元素的古树普洱茶原料特征研究

目的基于矿质元素鉴别古树普洱茶原料的产地。方法测定不同产地不同季节古树普洱茶原料中矿质元素,并对数据进行了单因素分析、主成分分析、系统聚类分析、Fisher判别分析。结果不同产区的古树普洱茶原料矿质元素:普洱茶区锌、钠、钙、铬含量较高,版纳茶区的锰、铜、钾含量较高,临沧茶区的铁、氟、稀土总量较高;不同产地古树普洱茶原料铁、钙存在极显著差异。春季古树普洱茶原料的铁、锰、锌、钾、钠、钙、镁、稀土总量较高,秋季古树普洱茶原料的铜、铬、氟含量较高,不同季节古树普洱茶原料铁、铜、钾、钠、钙、铬含量存在极显著差异。运用主成分分析可以很好地区分不同季节的古树普洱茶原料,但是不能很好区分不同产地的古树普洱茶原料;采用系统聚类分析方法不能区分不同产地古树普洱茶原料;采用Fisher判别分析方法可以较好地区分不同产地的普洱茶原料,总判别正确率为86.7%。结论茶叶中的矿质元素可以用于区分不同季节不同产地的古树普洱茶原料。     

桑叶绿茶中微量元素含量及浸出特征研究

采用火焰原子吸收分光光度法测定桑叶绿茶中Ca、Mg、Cu、Mn、Zn、Fe六种元素的含量,并在不同冲泡时间和不同冲泡次数条件下研究了桑叶绿茶中微量元素浸出量。结果表明,桑叶绿茶中微量元素总含量顺序为Ca>Mg>Fe>Mn>Zn>Cu,浸出液中各元素浸出量顺序为Mg>Ca>Zn>Fe>Mn>Cu,其中Mg最易浸出,Cu最不易浸出;不同冲泡时间微量元素浸出规律可用对数关系描述,不同冲泡次数微量元素浸出规律可用负指数关系描述。研究桑叶绿茶中微量元素的浸出特性有助于进一步研究桑叶中各元素存在的形态,并可为桑叶绿茶相关产品的开发提供一定的实验依据。     

不同浓度海水灌溉对库拉索芦荟中微量元素的影响

采用原子吸收分光光度法分析了不同浓度海水灌溉的3年生库拉索芦荟中Ca、Mg、Na、K、Mn、Zn、Fe、Cu、Ni、Pb、Cd、Cr共12种微量元素的含量。试验发现:各元素在芦荟中的含量差异较大,其中,Ca、Mg、Na、K含量丰富,Mn、Zn、Fe含量中等,而有毒重金属离子Cu、Ni、Pb、Cd、Cr含量很低;无论是凝胶还是全叶中,海水浓度对库拉索芦荟中Ca、Mn元素的影响很大,对其他各种元素的影响不大,但Cd离子的含量随海水灌溉浓度的升高呈略微上升趋势。     

基于F-AAS、GF-AAS对云南石榴蜂蜜中矿质元素进入途径研究

石榴蜂蜜为云南蒙自地区的特色蜂蜜。本文利用火焰原子吸收光谱仪(F-AAS)、石墨炉原子吸收光谱仪(GF-AAS)测定石榴蜂蜜、石榴植株各器官(根、茎、叶和花)及生境的土壤和水中9种矿质元素(K、Na、Pb、Cd、Zn、Mn、Mg、As和Cu)的含量。表明:石榴蜂蜜中K元素含量最高(283.68 mg/kg),Cd元素含量最低(0.008 mg/kg)。聚类分析和雷达图均显示石榴花对石榴蜂蜜中矿质元素含量的影响最大,其中K元素从花中进入到石榴蜂蜜的比例最大(37.79%);Cd元素的比例最少(0.46%)。相关性分析表明,石榴蜂蜜中的各矿质元素与植株各器官、水均有不同程度的显著相关,其中花中的K、Na、Zn、Mn和Mg,根中的Pb、Cd和As,水中的Na、Mn和As,茎中Pb和Mn,叶中的Zn元素均与石榴蜂蜜呈显著相关。本研究表明,石榴蜂蜜中的矿质元素除直接来源于"土壤-植株-花蜜"这个生物链外,还与环境和人类活动等因素有关。     

Effect of potassium,magnesium and sulphur applied in different forms of fertilisers on free amino acid content in leaves of tea (Camellia sinensisL)

Free amino acids in tea leaves are important chemical constituents that considerably influence the quality of tea, especially that of green tea. The present study was conducted to investigate the effects of the nutrients potassium, magnesium and sulphur on biomass production and amino acid accumulation in tea leaves in pot and field experiments. The results show that biomass production and the free amino acid contents in tea leaves increased considerably following the application of potassium and magnesium. Combined application of both nutrients produced the highest increment in free amino acids. The increased free amino acid content in tea leaves was accompanied by enhanced nitrate reductase activity. This indicates that potassium and magnesium application improved the nitrogen metabolism, leading to an increased synthesis of amino acids. A comparison between K₂CO₃ vs K₂SO₄ and MgO vs MgSO₄ revealed significantly higher amino acid contents in tea leaves when both potassium and magnesium were applied in the sulphate form, indicating that not only potassium and magnesium but also sulphur plays an important role in the accumulation of amino acids in tea leaves. A pot experiment using KCl and K₂SO₄ was carried out in order to compare the two commercially available potassium fertiliser forms in their effect on biomass production and the content of free amino acids in tea leaves. The results showed no difference on biomass production between the two fertiliser forms. However, whereas KCl tentatively depressed nitrate reductase activity and hence the accumulation of free amino acids, K₂SO₄ significantly increased the contents of these quality promoting constituents of tea leaves. The role of fertiliser composition, detrimental effects of accompanying anions, eg Cl⁻ and differences in nutrient availability (eg oxide≪sulphate form) and possible impact on soil chemistry as main reasons for the observations, being crucial aspects with regard to fertilisation of tea for good quality are discussed. © 1998 SCI.     

华南主要野生蔬菜的基本营养成分及营养价值评价

对华南主要的8种野生蔬菜守宫木、土人参、一点红、白仔菜、紫背菜、鳄嘴花、藤三七、塘葛菜和华南特产蔬菜菜心的基本营养成分作了较全面系统的分析。结果表明，8种野菜营养成分差异较大，其可食部分都含有较丰富的灰分、粗蛋白、粗脂肪、粗纤维和VC含量。8种野菜中检测出钾、磷、钙、镁、钠、铁、锌、锰、铜、镍、铅、镉、铬等无机元素，其中钾含量比菜心高3－6倍，为高钾低钠植物。守宫木、白仔菜、鳄嘴花等对有毒重金属的富集能力较强。     

Effects of potassium and magnesium nutrition on the quality components of different types of tea

In field experiments, the effects of potassium and magnesium nutrition on the quality components of different types of tea, including black tea, oolong tea and green tea, were studied. The results show that K and Mg fertilizer application increased the contents of free amino acids and caffeine of the various tea types with the maximum increase found in the treatment including both nutrients. The content of polyphenols in tea leaves was also increased by K application. The effect of Mg on polyphenol content was inconsistent. In general, Mg apparently decreased the content of polyphenols and only in case the soils were depleted of plant available K and Mg, a slight increase could be observed. The contents of theaflavins and thearubigins, important quality components of brewed black tea, were also increased by K application. Flavour compounds in brewed oolong tea were considerably improved by K and Mg application. © 1999 Society of Chemical Industry     

烟丝和卷烟纸中金属元素对自由燃烧速率的影响

采用火焰原子吸收法测定42个不同牌号卷烟烟丝、卷烟纸及烟灰中8种金属元素的含量,并研究金属元素含量对烟支自由燃烧速率的影响。结果表明:钾、钠、镁、锰、锌、铜与卷烟烟支自由燃烧速率关系密切。其中,钾对烟支自由燃烧速率具有促进作用、镁为抑制作用,其余元素则因来源(卷烟纸或烟丝)差异呈现不同的影响趋势。     

Improving the sensory and nutritional value of gluten-free bread

Bakery products, especially breads, are important part of everyday diet. Home-made breads are all the more crucial on the gluten-free diet, as commercially available breads without gluten are often unattractive. The study presents the recipe, nutritional characteristics (fat, protein, calcium, magnesium, sodium, potassium, copper, iron, zinc, manganese), costs and consumer acceptance of four easy to make home-made gluten-free breads. Partial substitution of bread-mix based on corn and rice (control bread) with teff flour, amaranth flour or quinoa flour significantly changed the content of the most of analysed nutrients, while their price was comparable. The highest nutritional benefits were found for protein, magnesium, potassium, calcium, zinc, iron and manganese in bread with teff and for magnesium, potassium, zinc and manganese in bread with amaranth. The highest consumer acceptance of people on gluten-free diet was noticed for breads with quinoa and teff.