加速溶剂萃取高效液相色谱-电感耦合等离子体质谱测定海产品中砷形态方法研究

目的建立加速溶剂萃取(PLE)与高效液相色谱-电感耦合等离子体质谱(HPLC-ICP MS)联用测定海产品中砷形态的方法,为食品安全风险监测提供参考方法。方法以50%甲醇-水为溶剂,采用快速溶剂萃取仪提取各形态的砷;利用阴离子交换柱分离,以O2为动态反应气消除质谱干扰,实现了As B、As(Ⅲ)、DMA、MMA、As(Ⅴ)5种形态砷的分离测定。结果 5种砷浓度在2.5μg/L~25μg/L时线性相关系数均≥0.999 0,检出限为0.1μg/L~0.2μg/L,相对标准偏差3.5%。实际样品加标回收率在80.1%~104.0%。结论方法具有快捷、准确、灵敏等优点,可分别用于无机砷、有机砷的测定,并可最大程度保留食品中砷的原始形态,便于进行形态分布研究。     

高效液相色谱-电感耦合等离子体质谱法同时测定海产品中6种砷形态的研究

目的建立高效液相色谱-电感耦合等离子体质谱联用(HPLC-ICP-MS)测定海产品中亚砷酸根As(Ⅲ)、砷酸根As(Ⅴ)、一甲基砷(MMA)、二甲基砷(DMA)、砷甜菜碱(AsB)和砷胆碱(AsC)6种砷形态的分析方法,了解海产品中砷的形态与含量。方法海产品经0.15mol/L硝酸溶液热提取后,高效液相色谱以色谱柱Dionex Ion Pac AS7(4mm×250mm,5μm)为分离柱,用碳酸铵为流动相进行梯度洗脱分离,用电感耦合等离子体质谱进行定量检测。结果 6种砷形态均达到良好分离,在2.5~150μg/L范围内有良好的线性关系,回收率82.0%~113.0%,相对标准偏差(RSD)5%;海产品中的砷主要以有机砷形式存在,砷甜菜碱含量较高。结论建立的砷形态分析方法简便、准确可靠,符合海产品砷形态检测的要求。     

HPLC-ICPMS测定海鱼中六种砷形态方法探讨

采用1%硝酸微波萃取进行提取,梯度洗脱的方式对六种砷形态(As B、As C、AsⅢ、As V、MMA、DMA)进行分离,HPLC-ICPMS(液相色谱-电感耦合等离子体质谱)测定海鱼中六种砷形态。对影响液相分离的各条件进行优化,得出六种砷形态的线性范围为1.0μg~200μg/L,相关系数r=0.999 6~1.000 0,检出限依次为As C:0.21μg/L、As B:0.21μg/L、DMA:0.14μg/L、MMA:0.12μg/L、AsⅢ:0.23μg/L、As V:0.21μg/L。加标回收率为82.2%~97.5%,相对标准偏差为0.8%~8.6%,该方法 12 min内能分离六种砷形态,前处理步骤简单,适用于海鱼中砷形态的测定。     

动物性海产品中砷形态分析方法的研究

目的 建立动物性海产品中砷甜菜碱(AsB)、亚砷酸盐(AsⅢ)、砷酸盐(AsⅤ)、二甲基砷酸(DMA)和一甲基砷酸(MMA)的液相色谱-在线紫外消解-氢化物发生-原子荧光光谱联用的测定方法(LC-UV-HG-AFS).方法 以90%甲醇为提取溶液,超声振荡提取后,提取液以N2浓缩至近干,加水溶解残渣后以正己烷萃取除去脂质成分,取下层清液,以超纯水定容至10 ml,过滤后进样分析;以0.2 mmol/L磷酸二氢铵(pH9.0)和20 mmol/L磷酸二氢铵(pH6.0)为流动相,梯度洗脱,以Hamilton PRPX-100柱分离,LC-UV-HG-AFS检测.结果 在给定的色谱条件下,AsB、AsⅢ、AsⅤ、DMA和MMA达到基线分离;各组分的检出限在0.0025～0.0032 mg/L之间,重复性和再现性＜10%,0.2 mg/kg添加水平的回收率＞85%;鱼、虾、贝样品中所含有的主要砷形态化合物为AsB,仅在某些贝类样品中检出微量AsⅢ和DMA;分别以定值参考物NBS 1566牡蛎组织和BCR 627金枪鱼考察总砷测定和砷形态分析的准确性,结果符合定值要求.结论 建立的LC-UV-HG-AFS方法适合于动物性海产品中砷形态化合物的特异性检测,测定结果准确可靠.     

离子色谱-电感耦合等离子体质谱法测定野生食用菌中6种砷形态

目的建立离子色谱-电感耦合等离子体质谱法(IC-ICP-MS)同时测定野生食用菌中砷甜菜碱(As B)、砷胆碱(As C)、二甲基砷(DMA)、一甲基砷(MMA)、亚砷酸As(Ⅲ)、砷酸As(Ⅴ)6种砷形态的方法。方法野生食用菌中砷形态用1%稀硝酸70℃超声提取1 h,离心后取上清液,残渣重复提取2次后合并上清液混匀,上清液经0.22μm滤膜过滤后通过阴离子色谱柱Dionex Ion Pac~(TM) AS7分离,2 mmol/L和100 mmol/L碳酸铵为流动相梯度洗脱,以电感耦合等离子质谱仪检测75As,外标法定量。结果 6种砷形态在0.5μg/L~50μg/L浓度线性关系良好,相关系数均为0.999 5,6种砷形态检出限为2μg/kg~8μg/kg,3个不同加标水平平均回收率为92.4%~109.1%,相对标准偏差7%。结论该方法具有灵敏度高、准确性好的特点,可用于野生食用菌中砷形态检测分析。     

超声辅助提取—高效液相色谱—电感耦合等离子体质谱法测定虾姑中无机砷的研究

目的 探索并建立超声辅助提取-高效液相色谱-电感耦合等离子体质谱法测定虾姑中无机砷含量的分析方法。方法 取1.0 g粉碎均匀的样品，加入15 ml 0.15 mol/L硝酸-0.45%过氧化氢混合溶液，90℃水浴超声辅助提取3 h,每隔30 min振摇一次。提取完毕后，用离心机将样液离心分离，取上层清液，过0.22μm滤膜，高效液相色谱法分离测定，分离柱是Thermo Dionex IonPac AS19(4 mm×250 mm),以10 mmol/L碳酸铵+2%甲醇与100 mmol/L碳酸铵+2%甲醇为流动相进行梯度洗脱，电感耦合等离子体质谱仪(ICP-MS)检测，标准曲线法定量，在15 min内完成了无机砷的分析测定。结果 在适宜条件下，无机砷可达到良好的分离，测定0μg/L～50μg/L浓度内As (Ⅲ)和As (V)的混合标准曲线，As (Ⅲ)和As (V)回归方程均呈良好的线性关系，相关系数均优于0.999 5,检出限为4.1μg/kg～5.8μg/kg, 3个浓度的加标回收率为97.1%～106.7%,相对标准偏差为1.7%～2.5%。结论 本试验建立的方法操作简单，提取...     

改进的湿法消解-原子荧光光谱法测定海产品中总砷

目的:建立准确稳定的测定动植物性海产品中总砷的分析方法。方法:采用硝酸、高氯酸、硫酸混合酸体系对海产品进行湿法消解,利用氢化物发生原子荧光光谱法测定样品总砷含量。结果:对植物性和动物性海产品分别进行最佳消解条件的摸索,同时优化检测条件。得出最佳条件如下:还原剂硼氢化钾(KBH4)浓度为2%;灯电流,60 mA;载气流量,400 ml/min;酸性介质,5%盐酸,砷在浓度范围0μg/L~40.0μg/L内线性关系良好,线性相关系数为0.9998,检出限为0.072μg/L。采用国家标准物质黄鱼GBW08573和海带GBW08517进行方法验证,所测结果均在标准参考值允许范围内,六次平行测定相对标准偏差小于3.8%。利用此方法对部分酒店的海产品进行监督检测,结果可靠。结论:该方法准确灵敏、简便高效,适用于海产品中总砷的测定。     

水中砷和硒的AFS-930型双道原子荧光光度计同时测定法

目的探讨应用AFS-930型双道原子荧光光度计,同时测定水中砷、硒的技术。方法用5%盐酸和5%硫脲-5%抗坏血酸混合试剂处理样品,并以0.2%氢氧化钾和1%硼氢化钾为还原剂,在2%的盐酸介质测定砷和硒。结果砷、硒回收率均大于95%,相对标准偏差小于3%,砷、硒的检出限分别为:As 0.10μg/L,Se 0.20μg/L。结论该方法精密度大,回收率高,操作简单,是测定水中砷、硒的可靠方法。     

高效液相色谱-原子荧光联用法快速测定海产品中汞形态

目的建立海产品中快速测定汞形态的方法。方法对海产品中甲基汞的液相色谱-原子荧光光谱联用测定方法进行了优化,避免使用C18小柱对样品的前处理进行净化,同时对流动相组成进行进一步的优化,使汞形态化合物的分离时间缩短至6 min以内。结果在优化条件下,3种汞形态的质量浓度为2μg/L~10μg/L时,标准曲线的浓度与其峰面积呈良好的线性关系,相关系数(r)均0.999。无机汞、甲基汞、乙基汞的检出限(S/N=3)分别为0.073μg/L、0.131μg/L、0.135μg/L;平均回收率分别为95.8%、97.5%、94.1%,相对偏差均10%。不同海产品的甲基汞加标回收率为83.7%~122.8%。结论该检测方法准确、快速、易操作,可满足海产品中甲基汞的检测。     

液相色谱-原子荧光联用法测定食用菌中4种砷形态

目的 建立1种液相色谱-原子荧光联用法测定食用菌中4种砷形态的方法。方法 取处理后的干食用菌样品,加入硝酸溶液,放入恒温箱浸提后,取上清液,经0.45μm有机滤膜过滤后,进入液相色谱,以Princen砷形态快速分析柱为色谱柱,用梯度洗脱进行分离,分离出的As(Ⅲ)、As(Ⅴ)、一甲基砷(MMA)、二甲基砷(DMA)等4种砷形态成分进入原子荧光光谱仪检测,根据保留时间定性,峰面积定量。结果 本法在质量浓度1～100μg/L范围内线性良好,相关系数r>0.999。取样0.5 g,提取体积为20 ml时,As(Ⅲ)检出限为6.20μg/kg, As(Ⅴ)为7.92μg/kg, MMA为2.72μg/kg, DMA为2.32μg/kg,加标回收率为90.4%～102.5%,相对标准偏差(RSD)为0.9%～2.2%。结论 本方法前处理简单、检测速度快、检出限低、准确度和精密度较高,可用于食用菌中4种砷形态的测定。     

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.