火焰原子吸收法测定茶叶中Mn Zn含量及溶出特性

目的:探讨某品牌红茶中Mn、Zn不同条件的溶出特性。方法:采用微波消解法、浸泡法、原子吸收法测定茶叶中Mn、Zn的含量。结果:随着温度、时间不同浸泡结果有规律性的变化;浸泡结果和消解结果有显著性的差异。结论:茶叶中Mn、Zn不同条件的溶出特性不同;浸泡结果远低于消解结果。     

牛蒡茶中微量元素溶出率及化学形态研究

目的:通过对牛蒡茶及浸泡液6种微量元素含量的检测,比较不同实验条件溶出率的差异。方法:采用不同浸泡水温和浸泡时间、不同浸泡次数及牛蒡茶清洗前后和浸泡液消化与否处理,用原子吸收法测定牛蒡茶及待测液的6种微量元素含量,比较溶出率的差异元素存在化学形态的关系。结果:牛蒡茶微量元素含量高,溶出率的顺序钙>锶>锰>锌>铜>铁,并且与浸泡时间和次数密切相关,溶出率高低与存在形态也相关。结论:结合微量元素含量和溶出率,牛蒡茶是一种很好的健康的微量元素补充食品,有开发利用价值。     

日照绿茶中6种微量元素溶出率的研究

目的:探讨日照绿茶中微量元素含量及溶出率。方法:用原子吸收分光光度计测定消化和浸泡两种不同处理下茶叶中微量元素的含量,以消化法测出的结果为基准,求茶叶浸泡液中各种微量元素的溶出率。结果:平均溶出率分别为Mg 21.9%、Cu 20.8%、Fe 2.45%、Zn 22.5%、Mn17.6%、Sr 20.3%。溶出率随浸泡次数增加而降低,总溶出量中80%的Mg、Cu、Zn、Sr、及10%左右的Fe和70%Mn在第1次浸泡中被溶出。结论:实验所得数据用于评估饮茶对6种微量元素的实际摄入量,指出茶叶不是这些元素的良好食物来源。     

茶叶中微量元素溶出率及保健作用研究进展

综述了茶叶中微量元素的组成,茶水中微量元素的溶出率与茶叶不同浸泡方式、不同浸泡时间、不同浸泡温度之间的关系以及茶叶中微量元素与其保健作用的关系。茶叶中微量元素的保健作用不但决定于茶叶本身微量元素的组成,还与微量元素的溶出率息息相关。     

电流氧化溶出计时电位法同时测定茶叶中的铅,铜

铅、铜是茶叶的两个重要的卫生指标，测定方法有原子吸收法、二硫腙比色法、极谱法〔１～３〕。近年来，溶出计时电位法测定铅、铜的方法报道〔４～６〕也较多，但都是采用介质中存在的溶解氧或加入Ｈｇ２＋作为氧化剂氧化溶出，而采用电流氧化溶出同时测定茶叶中的痕量铅、铜的方法尚未见报道。本文提出了在高效除氧体系ＨＣｌ－Ｆｅ３＋－ＫＮＯ３－ＶＣ介质中，用电流氧化溶出计时电位法同时测定茶叶中铅、铜的新方法，并对铅、铜的相互干扰及共存元素对铅、铜测定的影响作了较详细的研究。大量实验表明，该法具有仪器价廉，灵敏度高，选…     

涉水PE、PP-R铜嵌件浸泡液中铅镍的测定与分析

目的 了解输配水设备PE、PP-R铜嵌件浸泡液中铅、镍的溶出量,确定最能够反映铜嵌件实际使用工况下重金属溶出的浸泡方式。方法 采用4种浸泡方式对不同厂家的PE、PP-R铜嵌件进行浸泡,并采用电感耦合等离子体质谱(ICP-MS)对其溶出的Pb、Ni进行测定。结果 使用H59铜合金表面镀镍的PE、PP-R铜嵌件浸泡液中Pb、Ni溶出量远超《生活饮用水输配水设备及防护材料卫生安全评价规范》(2001)的要求,使用符合国家标准的H59铜合金且不镀镍的铜嵌件Pb、Ni溶出量则满足卫生规范,内部浸泡的浸泡液中Pb、Ni含量最高。结论 PE及PP-R铜嵌件生产厂家应严控材料选择,使用低铅黄铜,从而确保产品不污染水质。在浸泡实验时,仅计算管件内表面面积,每500 cm²加1 L浸泡液的浸泡方式能够模拟管件实际使用过程,反映真实的重金属溶出情况。     

多种条件下一次性发泡餐具中金属元素的浸出研究

目的 测定不同溶剂条件、微波条件下一次性发泡餐具中元素浸出状况,以期了解该种餐具的使用安全性.方法 采用ICP-MS(电感耦合等离子体质谱)法测定不同条件下一次性发泡餐具的元素浸出液.结果 一次性发泡餐具在4％乙酸溶液中浸泡时铅、铁、铝会有明显浸出,砷、锰、铜、镉、锌等元素则有一定量的浸出.在65％乙醇中浸泡时铅、锰、锌、铝、铁等元素有溶出,在水和正己烷条件下基本无浸出.在微波条件下,元素的浸出量会高出20％左右.结论 一次性发泡餐具在使用过程中会有多种元素浸出,从而污染食品,尤其在酸性条件下更为严重,微波可以加速元素的浸出过程.     

氢化物发生-原子荧光光谱法测定茶叶中微量砷和汞的含量

目的：测定茶叶及茶汤中砷和汞的含量。方法：微波消解氢化物发生-原子荧光光谱法。结果：龙井特级、碧螺春、云南滇红、铁观音、荔枝红茶、茉莉花茶、毛峰、螺旋苦丁茶8种茶叶样品中的砷、汞总量均低于国家标准（GB2762-2005）限量。对其中的螺旋苦丁茶、铁观音、碧螺春3种茶叶样品进行2次冲泡，测定茶汤中的砷、汞溶出量以及茶渣中残留的砷、汞含量。在优化的实验条件下砷、汞测量方法的检出限分别为0．167．ng/g、0．011ng/，加标回收率为85．4％～98．9％。结论：方法准确、可靠，可用于茶叶及茶汤中微量砷和汞的测定。     

贵州道地药材杜仲中微量元素的测定

目的：测定贵州10产地中药杜仲中镉、铜、铅、汞、砷和硒6种微量元素的含量。方法：采用湿法进行消化,用原子吸收分光光度法测定其镉、铜、铅元素的含量和原子荧光光度法测定其汞、砷、硒元素的舍量。结果：不同产地杜仲药材镉、铜、铅、汞、砷和硒6种微量元素含量有一定差异,其中汞含量均超出标准范围,砷含量均未超出标准范围,习水和安顺的药材含硒量相对其它产地较高。结论：不同产地杜仲药材镉、铜、铅、汞、砷和硒,6种微量元素含量有一定差异。     

市售几种茶叶及其汤汁中咖啡因和铅、铜的检测

目的:对收集到的六安市售的十个茶叶品种样品,分别进行咖啡因、铅和铜含量的检测,以了解其质量状况。方法:1 g茶叶 100 ml 100℃纯净水浸泡20 min所得茶汤中咖啡因的含量,采用HPLC法检测;利用FAA法检测铅、铜的含量。结果:被检茶样中铅含量在2.5952~4.6785 mg/kg之间、铜含量在7.3784~25.7182 mg/kg之间;茶汤中铅、铜溶出量均未检出;一泡茶汤中咖啡因含量在66.226~278.880 mg/L之间。结论:十个茶叶样品中铅铜含量均未超标,其一泡茶汤中咖啡因含量符合国标限量。     

ICP-AES测定花粉中10种微量元素的方法研究

目的建立花粉中10种微量元素的测定方法。方法采用微波消解法处理样品,电感耦合等离子体原子发射光谱化(ICP-AES)法测定铬、锌、铜、锰、砷、铁、铅、镉、硒和铝10种微量金属元素。结果 ICP-AES——微波消解法回收率为:93.2%～107.8%,相对标准偏差为1.58%～3.44%。结论 ICP-AES——微波消解法具有简便、快速、准确等特点,适用于花粉中10种微量金属的测定。     

基于ICP-MS探讨病人透析前后血中元素含量的变化

摘要:目的 探讨透析患者透析前后全血中矿物元素含量的变化,为透析病人提供治疗和保健依据。方法 采集透析病人透析前后的静脉血及透析液,前处理后利用电感耦合等离子质谱(ICP-MS)分析其中的矿物元素含量,并对透析前后的血中及透析液矿物元素含量进行配对t检验。结果 该分析方法的线性相关系数均在0.999以上,相对标准偏差在2.8%~5.5%之间,加标回收率在87%~108%之间。透析后,血液中钙、锰、铁、铜、锌、硒的含量较透析前小幅度升高,铬、砷、铅含量较透析前后变化不大;透析液中,铬、锰含量变化不大,但是铁、铜、锌、硒的含量均有不同程度的增加。结论 长期看,行透析治疗的病人,体内钙、锰、铁、铜、锌、硒的含量低于正常人。同时,存在血中铅、砷等短暂升高而引起的中毒的风险。     

ICP-MS法测定微波条件下陶瓷餐具中的元素浸出

目的:测定微波条件下陶瓷餐具的浸出元素,以期了解陶瓷餐具微波加热食品的安全性。方法:采用ICP-MS(电感耦合等离子体质谱)法测定不同微波条件下陶瓷餐具的元素浸出液。结果:浸出液中硒、银、锡、汞、等元素的含量小于检出限,砷、锰、铁、铜、镉、镍等元素的含量较低,铝、锌、铅等元素则有相对明显的浸出;元素的浸出量与微波的时间及微波后的浸泡时间成正比,与微波浸泡次数成反比。结论:在酸性微波条件下,陶瓷餐具中的部分元素会有一定量浸出,浸出量与微波的时间及微波后的浸泡时间成正比,浸出量随着浸泡次数的增加而减少,不具有持续效应。     

利用X—荧光光谱仪对14种茶叶及茶汤中不同元素进行定量分析

以14种市售的不同价格、不同产地、不同品级的茶叶为供试材料,利用X—荧光光谱仪对其所含元素成分进行定量分析,同时也对4种不同产地的茶叶浸泡,取不同时间段、不同层的茶水进行元素含量分析,此外还利用显微红外光谱仪对3种不同品种茶叶的有机官能团进行了测定。结果显示,不同品种茶叶中所含元素种类基本一致,但其含量存在一定差异,大多数元素在冲泡的前20 min便溶出到茶汤中、并大多集中在中上层。而3种茶叶中的有机官能团却基本相同。本实验结果为进一步研究茶叶的保健作用和冲泡方式等提供了较为科学的资料和数据。     

与饮用水接触的卫生防护涂料的浸泡实验方法

目的探讨与饮用水接触的卫生防护涂料浸泡实验的样品浸泡方法。方法选择与饮用水接触的卫生防护涂料的样品进行浸泡实验，分别采用4次96h不连续浸泡(即每隔24h换新的浸泡水)和4次96h连续浸泡，并将检验结果与按照《生活饮用水检验规范》(2001)规定的标准浸泡方法(30d6次)进行的实验结果进行比较。结果30d浸泡实验显示，色度、臭和味、肉眼可见物、挥发酚类、砷、铬、镉、铝、铅、四氯化碳、甲醛等11项指标均低于检出限，随着浸泡天数的增加，浑浊度、溶解性总固体、pH值、汞、三氯甲烷浓度的改变量的均值均呈下降趋势。采用4次96h不连续浸泡和4次96h连续浸泡后，色度、臭和味、肉眼可见物、挥发酚类、砷、铬、镉、铝、铅、汞、四氯化碳、甲醛等均低于检出限；随着浸泡天数的增加，浑浊度、溶解性总固体、三氯甲烷浓度均呈衰减趋势，耗氧量、pH值均呈波动趋势，4次96h不连续浸泡比4次96h连续浸泡的溶出物稍多。结论推荐4次96h不连续浸泡作为与饮用水接触的卫生防护涂料浸泡实验的标准方法。     

福建省地产茶叶中微量元素含量的分析

目的了解福建省不同地区不同品种茶叶中铁、锰、铜、锌、钴、硒、铬、镍等微量元素的含量分布,为茶叶种植、茶叶营养及卫生学提供科学依据。方法在福建省主要产茶地和市场随机抽取不同品种茶叶135份,用微波消解-电感耦合等离子体质谱法(ICP-MS)测定样品中微量元素含量。结果茶叶中8种微量元素含量组内变化趋势为锰铁锌铜镍铬钴≈硒,不同品种茶叶中8种微量元素的含量均不全相同,铁观音中锰元素含量最高,功夫红茶中铁、锌、铜和铬元素含量最高,白牡丹中镍元素含量最高,永春佛手中钴元素含量最高,正山小种中硒元素含量最高。闽北地区茶叶中铁、锌、铜、镍的平均含量高于闽南地区,差异均有统计学意义(P0.01),闽南地区的锰高于闽北地区,差异有统计学意义(P0.01),其他元素两地区相当(P0.05)。结论福建省地产茶叶中富含多种微量元素,且不同地区不同品种茶叶中各元素含量存在差异。     

Maternal exposure to arsenic, cadmium, lead, and mercury and neural tube defects in offspring

Arsenic, cadmium, lead, and mercury are neurotoxins, and some studies suggest that these elements might also be teratogens. Using a case-control study design, we investigated the relation between exposure to these heavy metals and neural tube defects (NTDs) in offspring of Mexican-American women living in 1 of the 14 Texas counties bordering Mexico. A total of 184 case-women with NTD-affected pregnancies and 225 control-women with normal live births were interviewed about their environmental and occupational exposures during the periconceptional period. Biologic samples for blood lead and urinary arsenic, cadmium, and mercury were also obtained for a subset of these women. Overall, the median levels of these biomarkers for heavy metal exposure did not differ significantly (P > 0.05) between case- and control-women. However, among women in the highest income group, case-women were nine times more likely (95% confidence interval (CI) 1.4-57) than control-women to have a urinary mercury 5.62 microg/L. Case-women were 4.2 times more likely (95% CI 1.1-16) to report burning treated wood during the periconceptional period than control-women. Elevated odds ratios (ORs) were observed for maternal and paternal occupational exposures to arsenic and mercury, but the 95% CIs were consistent with unity. The 95% CIs of the ORs were also consistent with unity for higher levels of arsenic, cadmium, lead, and mercury in drinking water and among women who lived within 2 miles at the time of conception to industrial facilities with reported emissions of any of these heavy metals. Our findings suggest that maternal exposures to arsenic, cadmium, or lead are probably not significant risk factors for NTDs in offspring. However, the elevated urinary mercury levels found in this population and exposures to the combustion of treated wood may warrant further investigation.     

Concentration, Distribution, and Comparison of Selected Trace Elements in Bed Sediment and Fish Tissue in the South Platte River Basin, USA, 1992–1993

During August–November 1992 and August 1993, bed sediment and fish liver were sampled in the South Platte River Basin and analyzed for 45 elements in bed sediment and 19 elements in fish liver. The results for aluminum, arsenic, cadmium, chromium, copper, iron, lead, manganese, selenium, silver, uranium, and zinc are presented here. All 12 trace elements were detected in bed sediment, but not all were detected in fish liver or in all species of fish. A background concentration of trace elements in bed sediment was calculated using the cumulative frequency curves of trace element concentrations at all sites. Arsenic, cadmium, copper, lead, manganese, silver, uranium, and zinc concentrations were greater than background concentrations at sites in mining areas or at sites that have natural sources of these elements. Trace element concentrations in fish liver generally did not follow the same patterns as concentrations in bed sediment, although concentrations of aluminum and cadmium were higher in fish liver collected at mountain sites that had been disturbed by mining. Concentrations of aluminum, arsenic, cadmium, chromium, copper, iron, lead, silver, and zinc increased in bed sediments in urban areas. Iron, silver, and zinc concentrations in fish liver also increased in urban areas. Concentrations of cadmium, copper, silver, and zinc in fish liver increased in the agricultural areas of the basin. Downstream changes in trace element concentrations may be the result of geological changes in addition to changes in land use along the river. Received: 5 April 1996/Revised: 27 July 1996     

绿茶保健作用研究

[目的]探讨绿茶保健作用。[方法]应用722分光光度仪测定绿茶中茶多酚含量,应用原子吸收分光光度仪测定微量元素含量及溶出率。[结果](1)绿茶等级越高其氨基酸、茶多酚的含量越高,锌含量亦越高。不同等级间茶多酚、微量元素锌含量差别甚大,茶多酚含量高者达36.2%,低者仅10.9%。锌含量高者达53.2μg/g,低者仅35.25μg/g。(2)铜、铁含量不高且品种间差别不大。(3)锰、氟、铝含量则随茶叶等级降低而升高,且品种间含量差别甚大。(4)5种绿茶中锌的溶出率均较高,达79.95%～88.26%,铜达70.6%～92.89%,氟达72.75%～95.63%,铁多为35%左右,锰36.08%～44.66%,铝8.81%～51.69%。[结论]高级别绿茶具有保健作用,低级别绿茶无益于健康。     

Trace elements in the Pacific oyster in Hong Kong

The concentrations of six trace elements (arsenic, cadmium, copper, lead, mercury, and zinc) were determined in samples of the Pacific oyster,Crassostrea gigas, taken from a retail market and from a local culture area. Concentrations of arsenic, mercury, and particularly cadmium, were frequently greater in samples purchased at the market than in those taken directly from the field. By contrast, levels of copper, lead, and zinc exhibited only minor differences in oysters from the two sources. The differences in the levels of arsenic, cadmium, and mercury are explained in terms of the marketing procedures; in summer, imported oysters dominate the market, and these oysters are relatively more contaminated by these three elements than are locally culturedC. gigas. The implications with respect to public health are discussed and element levels in oysters are compared to both public health regulations in Hong Kong and to metal concentrations in the same species from elsewhere.