反相高效液相色谱法同时测定酱腌菜中亚硝酸盐和硝酸盐

目的:建立反相高效液相色谱法测定酱腌菜中的亚硝酸盐与硝酸盐的方法.方法:样品经超声提取,再经石墨化炭黑柱(Envi-Carb柱)及PrelC-Ag和PrelC-Na联合柱净化处理后,以0.02 mol/L磷酸二氢钾一磷酸缓冲溶液(pH=3.20)为流动相,经Capcell PAK C18色谱柱分离,于210 nm处检测.结果:NO-2和NO3-在0.02～20 mg/L范围具有良好的线性,其相关系数均大于0.999,检出限均为0.8 mg/kg,实际样品的加标回收率分别为90.6%～101.3%和96.6%～104.8%,相对标准偏差≤5%.结论:此法简单、灵敏、准确,可用于同时测定酱腌菜中亚硝酸盐和硝酸盐.     

牛乳与乳粉中亚硝酸盐和硝酸盐的固相萃取离子色谱测定法

目的建立离子色谱同时测定牛乳与乳粉中亚硝酸盐和硝酸盐含量的方法。方法采用甲醇-乙腈对样品进行萃取并离心,上清液经C18小柱净化后,利用IonPac AS 11—HC柱分离和电导检测器测定,外标法定量。结果亚硝酸盐:线性范围0.02～0.20 mg/L,相关系数0.999 5,样品加标回收率90.0%～104.8%,RSD 3.5%,检出限为牛乳0.002 mg/kg,乳粉0.006 mg/kg;硝酸盐:线性范围0.20～2.0 mg/L,相关系数0.999 4,样品加标回收率90.0～105.8%,RSD 2.3%,检出限为牛乳0.006 mg/kg,乳粉0.03 mg/kg。结论该方法简便,快速,适合牛乳与乳粉中亚硝酸盐和硝酸盐含量的测定。     

离子色谱法同时测定婴幼儿奶粉中的硝酸盐和亚硝酸盐

[目的]建立离子色谱法同时测定婴幼儿奶粉中硝酸盐和亚硝酸盐含量的方法。[方法]样品经3%乙酸去除脂肪和蛋白质后,离心,上清液用0.22μm滤膜过滤,20℃温度下,经阴离子分析柱MetrosepASupp5-2504.0mm×250mm分离,电导检测器检测。[结果]硝酸盐、亚硝酸盐浓度分别在0.25～4.00mg/L、0.10～1.50mg/L范围内显良好的线性关系(r1=0.9997、r2=0.9999),方法回收率分别为90.2%～104%、91.0%～106%,RSD分别为1.83%～3.82%、1.35%～4.15%,最低检出浓度分别为0.04mg/L、0.05mg/L。[结论]实验表明,该法样品处理简单,测定快速,灵敏度高,满足婴幼儿奶粉中硝酸盐和亚硝酸盐含量的同时测定。     

酶水解-离子色谱法同时测定婴幼儿谷物辅助食品中亚硝酸盐和硝酸盐含量

目的 建立酶水解-离子色谱法同时测定婴幼儿谷物辅助食品中亚硝酸盐和硝酸盐的分析方法,调查市售婴幼儿谷类辅助食品中亚硝酸盐和硝酸盐含量。方法 在国家标准方法《食品安全国家标准食品中亚硝酸盐和硝酸盐的测定》(GB 5009. 33—2016)的基础上,采用α-淀粉酶水解样品后再进行提取、测定。结果 该方法避免了淀粉糊化对样品中亚硝酸盐和硝酸盐提取效率及测定结果的影响。该方法在亚硝酸盐(0 mg/L～1. 00 mg/L)、硝酸盐(0 mg/L～10. 00 mg/L)范围内具有良好的线性关系,相关系数(r)均在0. 999以上,加标回收率在99. 6%～107%,相对标准偏差(RSD)5%。结论 本方法采用α-淀粉酶水解淀粉完全后进行样品提取、测定,使得检测的结果更加准确可靠,适用于婴幼儿谷类辅助食品中亚硝酸盐和硝酸盐的测定。     

离子色谱法分析食用油中亚硝酸盐与硝酸盐

目的建立了食用油中亚硝酸盐和硝酸盐的离子色谱分析方法。方法样品用75℃温水在超声震荡下提取出硝酸盐与亚硝酸,该样品制备液先后经IC-:RP柱、IC-Ag柱和IC-Na柱净化后直接上机测定。结果本方法中NO_2~-标准浓度在0.0 mg~0.2 mg/L、N03~-标准浓度在0.0 mg~7.0 mg/L范围内,均具有较好线性0.999,方法的最低检出限分别为0.001 7 mg/L、0.002 5 mg/L回收率分别为98.3%~103.1%、99.4.%~102.6%,Rsd分别为2.10%,1.51%。结论本方法具有灵敏度高,操作简单等优点,适用于基层实验室对食用油中亚硝酸盐和硝酸盐含量的日常检测工作。     

积分安培检测-离子排斥色谱法测定食品中亚硫酸盐的研究

目的:建立积分安培检测-离子排斥色谱法测定食品中亚硫酸盐的方法。方法:采用ICE-AS1型离子排斥分离柱(9×250 nm),10 mmol/L H2SO4淋洗液,样品经10 mmol甘露醇+20 mmol Na2HPO4缓冲液浸泡提取。过滤后进样积分安培检测分析。结果:方法线性好,相关系数r=0.9999,相对标准偏差RSD3.5%,样品加标回收率在87.88%~101.79%,方法检出限为0.85 mg/kg。结论:该方法样品前处理简单,测定结果准确,重现性好,对分析测定食品中亚硫酸盐具有实用意义。     

离子色谱法改进后检测肉制品中亚硝酸盐含量

目的对离子色谱法检测食品中亚硝酸盐的方法进行了改进,优化了肉制品中亚硝酸盐检测时预处理、提取和净化方法,建立改进后离子色谱法定量检测肉制品中亚硝酸盐含量分析方法。方法样品捣碎后制成匀浆,经75℃水浴浸泡,加入饱和硼砂溶液和硫酸锌溶液沉淀蛋白质,除去上层脂肪,取上清液过滤后测定;以3.5 mmol/L碳酸钠-1.0mmol/L碳酸氢钠为淋洗液,采用AS14离子色谱柱,使用电导检测器检测肉制品中亚硝酸盐含量。结果在0.00-0.50 mg/L范围内硝酸盐线性关系良好,相关系数为0.9996,亚硝酸盐的方法检出限(3N/b)为0.17 mg/kg,加标回收率为93.2~102.50%,重复性(RSD)为5.66%以下。结论改进后方法简单、准确,易于操作,适用于肉制品中亚硝酸盐的定量测定。     

空气中亚硝酸盐和硝酸盐的离子色谱测定方法的研究

目的:建立空气中亚硝酸盐和硝酸盐的离子色谱测定方法。方法:本文采用超细玻璃纤维滤纸采集空气中亚硝酸盐和硝酸盐,用蒸馏水洗脱过滤后,经色谱柱分离,电导检测器检测,保留时间定性,峰高或峰面积定量。结果:空气中亚硝酸盐和硝酸盐的线性范围分别为0.5~30.0μg/m l和0.5~30.0μg/m l;相关系数分别为0.9997和0.9992;方法的最低检出限分别为0.5μg/m l和0.5μg/m l;若采集300 L空气进行测定,则最低检出浓度分别为0.017 mg/m3和0.017 mg/m3;相对标准偏差分别为0.39%~1.03%和0.45%~1.00%;样品洗脱效率分别为100.4%~103.2%和102.3%~106.8%;采样效率分别为94.8%~100.0%和92.7%~94.6%;样品在室温中至少可保存1周。结论:此法灵敏度高,选择性好,干扰少,是同时检测空气中亚硝酸盐和硝酸盐的好方法。     

离子色谱法同时测定饮用水中七种阴离子的含量

目的:建立同时测定饮用水中7种无机阴离子含量的测定方法。方法:样品用0.2μm滤膜过滤后直接进样,离子色谱法同时测定氟化物、氯化物、亚硝酸盐氮、溴化物、硝酸盐、硫酸盐和磷酸盐。色谱柱为:IonPac AS19型阴离子交换色谱柱(4 mm×250 mm i.d)和IonPac AG19保护柱;检测方式为:抑制型电导检测器。结果:本法相关性好(r>0.9993),精密度高(RSD%<3.0),样品加标回收率为95.0%～103.7%,检出限分别为:F-:0.0015 mg/L;Cl-:0.0010 mg/L;NO2--N:0.0019 mg/L;SO42-:0.0012 mg/L;Br-:0.0018 mg/L;NO3-:0.0013 mg/L;HPO24-:0.0023 mg/L。结论:该方法操作简单、快速、准确、线性范围广,可满足大批量水样检测分析要求。     

离子色谱法快速测定食品中的硝酸盐、亚硝酸盐

目的：应用离子色谱分析技术快速测定食品中的硝酸盐、亚硝酸盐。方法：纯水萃取食品中的硝酸盐、亚硝酸盐，经过离心、过滤、过C18柱、过滤膜后直接进样。结果：经过多次实验，该方法样品加标回收率：硝酸盐90．7％～99．7％、亚硝酸盐89．4％～104．3％；方法检出限：硝酸盐0．107mg／kg、亚硝酸盐0．087mg／kg。结论：该法操作简单、快速、准确、灵敏。     

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.     

The occurrence of antimicrobial substances in toilet,sink and shower drainpipes of clinical units: A neglected source of antibiotic residues

Antibiotics represent one of the most important drug groups used in the management of bacterial infections in humans and animals. Due to the increasing problem of antibiotic resistance, assurance of the antibacterial effectiveness of these substances has moved into the focus of public health. The reduction in antibiotic residues in wastewater and the environment may play a decisive role in the development of increasing rates of antibiotic resistance. The present study examines the wastewater of 31 patient rooms of various German clinics for possible residues of antibiotics, as well as the wastewater of five private households as a reference.To the best of our knowledge, this study shows for the first time that in hospitals with high antibiotic consumption rates, residues of these drugs can be regularly detected in toilets, sink siphons and shower drains at concentrations ranging from 0.02?μg·L^?1 to a maximum of 79?mg·L^?1. After complete flushing of the wastewater siphons, antibiotics are no longer detectable, but after temporal stagnation, the concentration of the active substances in the water phases of respective siphons increases again, suggesting that antibiotics persist through the washing process in biofilms. This study demonstrates that clinical wastewater systems offer further possibilities for the optimization of antibiotic resistance surveillance.     

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.