ICP-AES法同时测定天然植物中金属元素的研究

用微波消解和湿热消解两种前处理方法对海南天然植物荔枝和茄子进行对比处理,用电感耦合等离子体发射光谱法对其中的铁、镍、锰、铜、钾、锌、镁、钙等8种元素含量进行了测定。测定数据证明微波消解方法优于传统的湿热消解法。将微波消解前处理技术优化后再采用微波消解处理时方法的回收率为92.99%~115.57%,RSD<10.0%,各元素的测定检出限也表明该方法更快速、方便,测定结果准确可靠。     

奶粉中5种营养元素的微波消解火焰原子吸收测定法

目的建立奶粉中5种营养元素的火焰原子吸收测定方法。方法利用微波消解处理样品,火焰原子吸收法测定奶粉中钙、镁、铁、锌、铜。结果方法检出限在0.050~0.11μg/ml,平均回收率为92.8%~103%,样品进行6次平行测定,RSD为0.56%~2.31%。结论方法具有快速、简便、灵敏、准确的优点,适于奶粉中5种营养元素的测定。     

面制食品中铝测定前处理方法的研究与改进

目的通过对食品中铝测定3种不同前处理方法的比较,找出最佳的方法。方法采用干法、湿法、微波消解3种前处理方法对相同面食样品进行处理,分光光度法测定其铝的含量,分别进行加标回收试验和精密度试验。结果湿法消解、干法消解和微波消解的回收率依次为:95%~105%、97%~102%、98%~102%,精密度依次为0.8%~1.5%、0.3%~0.8%、0.2%~0.6%。结论 3种方法的回收率和精密度没有太大区别,均能满足实验要求。但是在实验过程中,微波消解法具有操作简单,试剂用量少,取样量少等诸多优点。微波消解法为较优的前处理方法。     

两种处理方法测定奶粉中锌的比较

在GB／T 5413．21-1997婴幼儿配方食品和乳奶粉钙、铁、锌、钠、钾、镁、铜和锰的测定中,样品前处理采用干法消解,即样品经炭化、灰化后定容测定,而我们根据实验室条件对该方法进行了改进,实验结果报告如下。1材料与方法1．1主要仪器与试剂WFX-1E2型原子吸收光度计(北京第二光学仪器厂产)HL-1锌特种空心阴极灯;WR-3A微波消解     

微波消解—原子吸收光谱法测定大蒜中镁钙锌铜锰铁的含量

用微波消解大蒜样品,用原子吸收光谱法测定大蒜中镁、钙、锌、铜、锰、铁的含量。结果表明,微波消解时间短,操作简单,消化过程节省试剂,减少环境污染。原子吸收光谱法测定大蒜中的这几种元素,方法快速简便,加标回收率为99.6%~100.3%,相对标准偏差(RSD)≤0.725%,测定结果准确。在大蒜中这几种对人体健康非常有益的元素的含量都比较丰富。     

电感耦合等离子体发射光谱法测定奶粉中的9种元素

目的探讨用电感耦合等离子体发射光谱法测定奶粉中钙、铁、锌、钠、钾、镁、铜、锰、磷9种元素的含量。方法用微波消解法处理奶粉样品,然后运用电感耦合等离子体发射光谱法分析样品,同时探讨了最佳消解奶粉样品和分析样品的条件。结果电感耦合等离子体发射光谱法测定中9种元素的方法检出限为0·05~50mg/kg,相对标准偏差为0·3%~4·5%,加标回收率为91·0%~105·8%。结论该方法具有操作简便、反应彻底、多种元素同时测定、检出限低、线性范围宽、干扰小等优点,并具有良好的准确度和精密度,适合奶粉中微量元素和常量元素的测定。     

用ACP—AES法测定头发中微量元素铁锰铜锌

目的:探索并建立快速测定头发中铁锰铜锌含量的方法。方法:微波消解头发样品,用ACP-AES法测定头发中微量元素铁锰铜锌。结果:标准曲线在0.1~1.0×10-6范围内线性良好,相关系数均为0.999以上,测定方法检出限不大于4.5μg/L,测定值均在标准物质标准不确定范围内,相对标准偏差均小于6%。结论:方法适于头发中多种微量元素的测定。     

不同消解方式对电感耦合等离子体质谱法测定灵芝中锗的影响

目的 为电感耦合等离子体质谱法测定灵芝中锗建立合适的前处理方法。方法 采用微波消解、高压罐消解、传统湿法消解和干法消解对选取的灵芝样品进行前处理。使用电感耦合等离子体质谱仪测定锗的含量,同时测定回收率和精密度,并对检测结果进行统计分析。结果 4种方式消解后检测结果经单因素方差分析多重比较(LSD法)可知微波消解与高压消解罐消解的结果差异无统计学意义(P> 0.05),而传统湿法消解、干法消解与高压罐消解、微波消解的结果差异有统计学意义(P <0.05)。微波消解和高压罐消解的测定结果回收率为79.78%～100.90%,精密度分别为12.99%、1.85%,检出限分别为0.002 5 mg/kg、0.001 6 mg/kg。结论 灵芝消解时需加入少量氢氟酸。消解完成得到的溶液澄清但有少量不可溶残渣时应在进样前经0.22μm聚四氟乙烯微孔滤膜过滤。微波消解和高压罐消解方法更适用于灵芝的消解。     

微波消解—磷钼蓝分光光度法测定奶粉中的磷

目的建立用微波消解进行奶粉前处理,磷钼蓝分光光度法测定奶粉中磷含量的新方法。方法分别用酸消解法及微波消解法消解奶粉样品,消解液按国标方法—磷钼蓝分光光度法显色后于660nm波长处测定吸光度;并考察了溶液吸光度随时间变化情况及减少显色剂用量对测定结果的影响。结果标准系列磷含量在0～60μg时,磷含量与吸光度成线性,相关系数0.9999;奶粉经微波消解前处理测得的磷含量,与国标的酸消解法相比差异无显著性;测定奶粉标准物质,测定值在标准参考值标识范围内。结论该微波消解条件对奶粉进行前处理,操作简单、快速,试剂用量少,结果准确,适合于奶粉中磷含量的测定。     

氢化物发生-原子荧光光度法测定紫菜粉中总砷的几种前处理方法

目的通过测定经不同前处理方法处理的紫菜粉样品中的砷含量,比较各种前处理方法的消化效果,选择最优消化条件。方法紫菜粉分别用湿法消化(不同混酸)、干灰化法、微波消化后,采用氢化物发生-原子荧光光度法测定砷含量,通过对结果的比较,选择最佳消化方法。结果在灯电流为30mA,负高压为280V,载流为5%盐酸时,砷的浓度在0~80μg/L时线性关系良好,相关系数为0.999 9。不同的消化方法测定结果不同,湿法消解法相对于干灰化法、微波消解法更适用于紫菜粉中砷的测定,结果更接近真值。湿法消化的回收率为91.90%~101.30%,相对标准偏差为3.38%~4.01%。常见干扰元素锑、铅、镉、铜、锌对测定没有影响。结论湿法消化更适合氢化物发生-原子荧光光度法测定紫菜粉中的砷,采用8.00ml HNO3+2.00ml HClO4+0.60ml H2SO4的混酸比例,测定结果最理想。微波消解和干灰化法由于消解不完全导致测定结果偏低。     

NICU新生儿血清磷镁钙铁锌铜检测结果分析

目的:分析NICU新生儿静脉血清部分电解质、微量元素的特点。方法:出生24h内采集济南市妇幼保健院302例新生儿静脉血,采用Bayer ADVIA CHEMISTRY SYSTEM测定血清磷、镁、钙、铁、锌、铜,并对结果进行分析,根据不同胎龄、体重、性别、分娩方式等进行比较,总结其特点。结果:302例新生儿静脉血清部分电解质、微量元素(mmol/L)为磷:2·21±0·45、镁:1·07±0·26、钙:2·06±0·31、铁:10·49±7·28、锌:12·87±4·00、铜:8·37±3·39。不同胎龄新生儿静脉血清电解质、微量元素比较,镁、钙、锌、铁有统计学意义,磷、铜无统计学意义。不同体重新生儿静脉血清电解质、微量元素比较,镁、钙、锌有统计学意义,磷、铁、铜无统计学意义,尤其是锌在早产儿、低出生体重儿反而高。除镁在不同分娩方式新生儿有显著差异外,不同性别、分娩方式新生儿静脉血清电解质、微量元素比较,均无统计学意义。结论:电解质、微量元素对新生儿的生长发育很重要,不同胎龄、体重新生儿静脉血清电解质、微量元素各有特点,应注意检测和分析。     

Detection of Helicobacter pylori in bovine, buffalo, camel, ovine, and caprine milk in Iran

Helicobacter pylori infection in humans is one of the most common infections worldwide. However, the origin and transmission of this bacterium has not been clearly explained. One of the suggested theories is transmission via raw milk from animals to human beings. This study was conducted to determine the prevalence rate of H. pylori in bulk milk samples from dairy bovine, buffalo, camel, ovine, and caprine herds in Iran. In the present study, 447 bulk milk samples from 230 dairy bovine, buffalo, camel, ovine, and caprine herds were collected in four provinces and tested for H. pylori by cultural method and polymerase chain reaction (PCR) for the detection of the ureC (glmM) gene. The animals whose milk samples collected for this study were clinically healthy. Using the cultural method, three of 447 milk samples (0.67%), including two sheep (2.2%) and one buffalo (1.6%) milk samples, were found to be contaminated with H. pylori. H. pylori ureC gene was detected in 56 (12.5%) of milk samples, including 19 cow (14.1%), 11 sheep (12.2%), nine goat (8.7%), two camel (3.6%), and 15 buffalo (23.4%) milk samples. Using PCR method, there were significant differences (p<0.05) in the level of contamination with H. pylori between milk samples collected from different species. The present study is the first report of the isolation of H. pylori from raw sheep and buffalo milk in Iran and the first demonstration of H. pylori DNA in camel and buffalo milk.     

Effects of Mumps Outbreak in Hospital,Chicago, Illinois,USA, 2006

In 2006, nearly 6,000 mumps cases were reported in the United States, 795 of which occurred in Illinois. In Chicago, 1 healthcare institution experienced ongoing transmission for 4 weeks. This study examines the outbreak epidemiology and quantifies the financial affect on this organization. This retrospective cohort study was conducted through case and exposure identification, interviews, medical record reviews, and immunologic testing of blood specimens. Nine mumps cases resulted in 339 exposures, 325 (98%) among employees. During initial investigation, 186 (57%) of the exposed employees had evidence of mumps immunity. Physicians made up the largest group of noncompliers (55%) with mumps immunity testing. The cost to the institution was $262,788 or $29,199 per mumps case. The outbreak resulted in substantial staffing and financial challenges for the institution that may have been minimized with readily accessible electronic employee vaccination records and adherence to infection control recommendations.     

Concentrations of Metals in Water,Sediment, Biofilm,Benthic Macroinvertebrates,and Fish in the Boulder River Watershed,Montana, and the Role of Colloids in Metal Uptake

To characterize the partitioning of metals in a stream ecosystem, concentrations of trace metals including As, Cd, Cu, Pb, and Zn were measured in water, colloids, sediment, biofilm (also referred to as aufwuchs), macroinvertebrates, and fish collected from the Boulder River watershed, Montana. Median concentrations of Cd, Cu, and Zn in water throughout the watershed exceeded the U.S. EPA acute and chronic criteria for protection of aquatic life. Concentrations of As, Cd, Cu, Pb, and Zn in sediment were sufficient in the tributaries to cause invertebrate toxicity. The concentrations of As, Cu, Cd, Pb, and Zn in invertebrates from lower Cataract Creek (63, 339, 59, 34, and 2,410 μg/g dry wt, respectively) were greater than the concentrations in invertebrates from the Clark Fork River watershed, Montana (19, 174, 2.3, 15, and 648 μg/g, respectively), that were associated with reduced survival, growth, and health of cutthroat trout fed diets composed of those invertebrates. Colloids and biofilm seem to play a critical role in the pathway of metals into the food chain and concentrations of As, Cu, Pb, and Zn in these two components are significantly correlated. We suggest that transfer of metals associated with Fe colloids to biological components of biofilm is an important pathway where metals associated with abiotic components are first available to biotic components. The significant correlations suggest that Cd, Cu, and Zn may move independently to biota (biofilm, invertebrates, or fish tissues) from water and sediment. The possibility exists that Cd, Cu, and Zn concentrations increase in fish tissues as a result of direct contact with water and sediment and indirect exposure through the food chain. However, uptake through the food chain to fish may be more important for As. Although As concentrations in colloids and biofilm were significantly correlated with As water concentrations, As concentrations in fish tissues were not correlated with water. The pathway for Pb into biological components seems to begin with sediment because concentrations of Pb in water were not significantly correlated with any other component and because concentrations of Pb in the water were often below detection limits.     

Reference intervals of cadmium,lead, and mercury in blood,urine, hair,and nails among residents in Mansoura city,Nile delta,Egypt

A random sample of 68 males and 25 females who reside in Mansoura city, Egypt, was examined for concentrations of cadmium, lead, and mercury in blood, urine, hair, and nails. The effect of gender and smoking on such levels was studied. The influence of dental amalgam on the levels of mercury in these biological samples was also examined. The results obtained show that only blood lead, which increased among males, was affected by gender. Blood levels of cadmium and lead as well as hair lead appeared to increase with smoking habit. Mercury levels in blood and urine were related to the presence of dental amalgam fillings. International comparisons between our results and the corresponding levels in other localities in the world showed that there were environmentally related variations in terms of cadmium levels in hair, lead levels in blood, urine, hair, and nails, and mercury levels in blood, hair, and nails. In conclusion, reference intervals of cadmium, lead, and mercury in the biological samples are environmentally related parameters. Some factors, such as gender, smoking habit, and the presence of dental amalgam fillings, may affect such levels and therefore should be considered.