微波消解-原子荧光法测定食用植物油中的总砷

砷是食品卫生监督检验中的一项重要指标,测定植物油中砷,样品前处理方法为湿法消化和法干灰化.这两种方法耗时长、易损失,对环境污染严重.微波消解样品则具有分解迅速、过程易控制、操作环境整洁等优点.本文以微波消解仪消化食用植物油样品,用原子荧光光度计测定其中的砷含量,与湿法敞口消化进行对比实验,得到满意结果.     

微波消解-原子荧光法测定食用植物油中的总砷

砷是食品卫生监督检验中的一项重要指标，测定植物油中砷，样品前处理方法为湿法消化和法干灰化。这两种方法耗时长、易损失，对环境污染严重。微波消解样品则具有分解迅速、过程易控制、操作环境整洁等优点。本文以微波消解仪消化食用植物油样品，用原子荧光光度计测定其中的砷含量，与湿法敞口消化进行对比实验，得到满意结果。     

食品中铝含量测定不同消解方式的研究与质量控制

目的找出适合于食品中铝的消解方法。方法分别采用干法消解、湿法消解、微波消解、高压消解4种方式对样品进行前处理,然后通过分光光度法测定食品中铝的含量。结果干法消解的回收率不稳定且偏低,精密度差;湿法消解、微波消解和高压消解的回收率为95.5%~103.0%,精密度RSD5.0%,3种方法处理面制食品所得结果差异无统计学意义(P0.05)。结论干法消解不适合用于食品中铝的测定,湿法消解、微波消解和高压消解适合于面制食品中铝的测定,且这3种消解方法的精密度和准确度均能达到满意的效果,但湿法消解、微波消解不宜用于植物性含铝样品的测定,植物性含铝样品的测定应采用高压消解方法。     

对海鱼粉中总砷含量的不同消解、检测方法对比探讨

目的对国家食品安全风险评估中心下发的HMRL1601海鱼粉质控样品中总砷含量进行测定,探讨最优检测方法。方法对国家标准方法推荐的电感耦合等离子体质谱法、原子荧光法的前处理条件进行优化,使用优化后的最佳条件检测并进行比对。结果采用原子荧光法检测总砷时,湿法消解比微波消解前处理效果好,而在使用湿法消解-AFS法时,采用硝酸-高氯酸-硫酸体系消解效果好;对于电感耦合等离子体质谱法测定样品中的总砷,微波消解比压力罐消解前处理效果好;2种方法进行比较时,微波消解-电感耦合等离子体质谱法测定的海鱼粉中总砷含量较为准确,而湿法消解-原子荧光法检测的结果相对偏低。结论相较于湿法消解-原子荧光法,微波消解-电感耦合等离子体质谱法更适合测定海鱼粉类有机砷含量较高的样品。     

海产品中总砷的消解方法研究

目的:寻找一种最佳的消解方法以测定海产品中的总砷。方法:分别以干法消化、湿法—干法消化、微波—干法消化3种消化方法原子荧光法测定海产品中总砷含量。结果:采用湿法—干法测定回收率最高,重现性最好,操作简便,方法可靠。结论:可以以湿法—干法作为海产品中总砷的消解方法。     

不同预处理方法测定米渣中Zn、Fe、Se、Pb元素的比较研究

目的：为测量微量元素的含量提供参考依据。方法：使用常规干法灰化、普通湿法消化、微波消解方法分别对米渣进行预处理,用火焰原子吸收法（FAAS）测定其中的Zn、Fe、Se、Pb等4种微量元素的含量。结果：3种方法测得Zn含量接近,普通湿法及微波消解测得Fe、Pb含量较高,微波消解测得Se含量较高;精密度高低依次为：微波消解,普通湿法消化,常规干法灰化;回收率：微波消解接近100%,常规干法灰化回收率相对比较低,普通湿法消化回收率略微偏高。结论：不同预处理方法对测得结果有一定影响,微波消解技术具有溶样能力强、速度快、损失小、污染少、试剂空白值低等优点,可用于多种微量元素的测量。     

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。     

食品中总砷测定的3种前处理方法比较

目的比较食品中总砷测定的3种前处理方法,为选择总砷测定样品前处理方法提供参考依据。方法采用微波消解、硝酸-高氯酸-硫酸消化法和干消化法分别处理芹菜、胡萝卜、黄豆、大米、鸡肉、紫菜、鱼粉、牡蛎8种标准物质,然后采用氢化物发生-原子荧光光度法测定。结果对于紫菜、鱼粉、牡蛎,用干消化法消解后检测得到满意结果,用微波消解和湿法消化测定的结果明显偏低。对于芹菜、胡萝卜、黄豆、大米、鸡肉等标准物质,用3种前处理方法消解样品测定的结果均在标准值范围内。其中微波消解法平行样结果误差最小,回收率最高(91.3%~98.2%),操作简单,消化时间短。结论干消化法消解过程中虽然有所损失,回收率低,平行样误差大,但用于含有大量有机砷的样品消解,其结果较满意。其他2种前处理方法处理后的样品结果明显偏低,因此不可用。     

食品中铅镉重金属检测前处理方法的探讨

目的采用三种不同的前处理方法消化处理食品,以测定食品中铅镉等重金属,用以探讨三种前处理方法各自的优缺点。方法采用微波消解仪,电热板湿法消解,全自动消解仪消化处理食品样品,最后用石墨炉原子吸收光谱法测定样品中铅镉的含量。结果微波消解~([1-3])测定标准物质的准确度高,空白本底值低,前处理时间短,两种元素的回收率都比较高。电热板湿法消解适用于大量样本的处理,但准确度较低,空白本底值高,回收率偏低,试剂消耗量大。全自动消解仪自动完成消化前过程,可同时消化多个样品,准确度较高,空白本底值低,回收率较高,试剂消耗量大。结论采用微波消解进行样品前处理,具有快速、准确等优点,是比较理想的前处理方法,全自动消解仪更适合大批样品的前处理。     

微波消解法与湿法消解法在测定食品总砷中的比较

目的探讨微波消解法和湿法消解法在前处理食品(米粉和麦粉)中对食品总砷含量测定结果的影响。方法根据国家标准GB 5009.11-2014总砷中第二法(氢化物发生原子荧光光谱法),分别采用微波消解与湿法消解法对质控样品和试样样品消解处理后进行总砷含量测定。结果两种处理方法测定食品(米粉和麦粉)中总砷,其含量为0.726 mg/kg时,两法精密度、准确度都较高(RSD2%,回收率为112%115%),试样样品检测结果差异无统计学意义(t=0.723,P0.05);在总砷含量为0.317 mg/kg时,湿法消化检测结果准确性很高(RSD2%,用"z-比分数"法对测试结果进行评价,z值均≤2),而用微波消解法检出总砷含量为0.222 mg/Kg,仅为质控样品含量的70%(RSD=2.8%),内质控样品两种方法检测结果差异有统计学意义(t=7.491,P0.05)。国标规定,谷物中总砷含量限值为0.5 mg/kg,本次试验以此值为分界值,低于0.5 mg/kg的样品称为总砷含量较低的样品,而高于0.5 mg/kg的样品称为总砷含量较高的样品。结论微波消解法和湿法在消解麦粉和米粉样品时,总砷含量高,两种方法测定结果一致性好。样品总砷含量低时,湿法消解处理待测样品,检测结果可靠。     

Calcium intake in the elderly: validation of a dietary questionnaire

Epidemiological studies of calcium and osteoporosis have been hampered by the lack of a suitable tool for assessing calcium intake. This report describes a new frequency and amount questionnaire for measuring present and past calcium intake in the elderly. The validity of the questionnaire was tested against two commonly used standards of dietary assessment, five-day duplicate diets and seven-day weighed dietary inventories. The resulting correlation coefficients were, respectively, r = 0.76 and r = 0.69, while that for repeatability was r = 0.84. Furthermore, the questionnaire categorized subjects into thirds of the distribution of intake with almost no gross misclassification. It is suggested that the present findings may be extended to the majority of normal, healthy elderly subjects, implying wide application for the questionnaire in the assessment of calcium intake in the elderly.     

Self-reported health problems among Swedish miners one year after unemployment

Unemployment is considered to be a public health concern sincedeterioration in the health of the unemployed is often anticipated.However, for some groups, such as miners, unemployment mightimprove health due to a cessation of potentially harmful occupationalexposures. This study evaluates the health of 79 miners in oneSwedish iron-ore mine, and 226 age-matched controls from thegeneral population, during one year after the closure of themine. The participants received a questionnaire regarding medicalhistory and subjective symptoms at the beginning of the studyperiod, and after one year. Statistically significant negativeeffects on self-reported health attributable to unemploymentwere not found, although neuropsychiatric symptoms were morecommon among the unemployed miners. The miners reported a statisticallysignificant improvement in grip force (p=0.031). They had asignificantly higher prevalence of symptoms associated withmining related exposures when compared with the population controls;pain in the upper extremities [relative risk (RR)=2.27, 95%confidence interval (Cl)=1.44–3.59), back pain (RR=1.84;Cl=1.237–2.75), vasospastic disease of the fingers (RR=2.05;Cl=1.18–3.57) and obstructive respiratory symptoms (attacksof dyspnea and wheezing: RR=3.67; Cl=1.167–11.6).     

Excès de cas humains et animaux de tularémie en France au cours de l’hiver 2007–2008 : émergence ou phénomène isolé ?

Context

Tularemia is a zoonosis affecting humans and hares in France. We describe the results of surveillance in both species, in 2007 and 2008.

Methods

Human tularemia cases are mandatorily notifiable in France since 2003. In hares, surveillance relies on volunteer hunter associations in all districts of the country. Data from mandatory reports and volunteer surveillance in 2007/2008 were analyzed and compared with previous results.

Results

In 2007/2008, 144 cases were reported in humans and 117 cases in hares. This was a 100% increase compared to previous years. Human cases differed from those of previous years only by the frequency of contact with breeding animals. Human cases without any documented risk exposure were also more frequent.

Conclusion

An increase of tularemia cases occurred in 2007/2008 in both species. Complementary studies are needed to identify the species reservoir in France to understand the causes of this peak of cases.     

Occupational health hazards in mining: an overview

This review article outlines the physical, chemical, biological, ergonomic and psychosocial occupational health hazards of mining and associated metallurgical processes. Mining remains an important industrial sector in many parts of the world and although substantial progress has been made in the control of occupational health hazards, there remains room for further risk reduction. This applies particularly to traumatic injury hazards, ergonomic hazards and noise. Vigilance is also required to ensure exposures to coal dust and crystalline silica remain effectively controlled.     

Manufacture and use of nanomaterials: current status in the UK and global trends

This paper provides an overview of the production and use of nanomaterials (NMs), particularly in the UK. Currently, relatively few companies in the UK are identifiable as NM manufacturers, the main emphasis being the bulk markets in metals and metal oxides, and some niche markets such as carbon nanotubes and quantum dots. NM manufacturing in the UK does not reflect the global emphasis on fullerenes, nanotubes and fibres. Some assumptions have been made about the types of NM that are likely to be imported into the UK, which currently include fullerenes, modified fullerenes and other carbon-based NMs including nanotubes. Many university departments, spin-offs and private companies have developed processes for the manufacture of NMs but may only be producing small quantities for research and development (R&D) purposes. However, some have the potential to scale up to produce large quantities. The nanotechnology industry in the UK has strong R&D backup from universities and related institutions. This review has covered R&D trends at such institutions, and appropriate information has been added to a searchable database. While several companies are including NMs in their products, only a few (e.g. manufacturers of paints, coatings, cosmetics, catalysts, polymer composites) are using nanoparticles (NPs) in any significant quantities. However, this situation is likely to change rapidly. There is a need to collect more information about exposure to NPs in both manufacturing and user scenarios. As the market grows, and as manufacturers switch from the micro- to the nanoscale, the potential for exposure will increase. More research is required to quantify any risks to workers and consumers.     

深圳公立医院管理体制改革制度设计

深圳公立医院管理体制改革实行政事分开、管办分开,在理事会架构下按法定机构模式组建市医管中心,落实公立医院运营管理自主权.作者从当前公立医院管理体制的弊端入手,介绍了深圳市进行公立医院管理体制改革的基本思路及改革方案设计的主要举措,深入剖析了的改革方案的特点,并对改革效果进行了预测.     

Effects of nitrogen dioxide on red blood cells of rats: Changes in components of red cell membranes during in vivo exposure to NO2

Red cell membranes, prepared from red blood cells of rats exposed to 4, 10, or 20 ppm nitrogen dioxide (NO₂) for 1 to 10 days, were examined for evidence of changes in membrane components. Appreciable changes were not found in contents of phospholipid and cholesterol during exposure to 10 ppm NO₂. By contrast, protein content altered with the time of exposure. Moreover, changes in protein composition were observed by employing sodium dodecyl sulfate — polyacrylamide gel electrophoresis. Twenty-four-hour exposure to NO₂ at the concentration above 10 ppm resulted in a marked increase in the percentage of lysophosphatidylethanolamine (LysoPE) to the total phospholipids. The prolonged exposure to 10 ppm NO₂ gave rise to a further increase in LysoPE, whereas the percentage of phosphatidylethanolamine (PE) showed a gradual decrease. A 1-day exposure to 4.0 ppm NO₂ also caused an increase in sialic acid content and decreases in those of PE and hexose. In addition to contents of these components the percentage of LysoPE increased 5 days after exposure and the elevated values were maintained up to the end of exposure period. These results demonstrate that red blood cells in circulation exhibit different membrane properties in terms of lipid and carbohydrate composition during 10 days of exposure to 4.0 ppm NO₂.     

Investigating clusters in the workplace and beyond

Clusters of disease are common and occur in the workplace and in the general community. They often arouse considerable concern among the population. Investigations have sometimes lead to exciting new knowledge, but in general the investigation of clusters is difficult and often unrewarding, especially for community clusters. In the workplace, investigations are more likely to find associations and even new causes, but still many clusters remain enigmatic. Despite this, there are many reasons for investigating clusters, including allaying community concern and identifying uncontrolled exposures. A structure for investigating clusters in the workplace is suggested.