GC-MS/MS法测定动物性食品中的克伦特罗残留量

[目的]研究测定动物组织中克伦特罗残留量的GC-MS/MS分析方法。[方法]应用GC-MS/MS技术,采用二级质谱母离子特有的子离子碎片信息进行定性及定量分析。[结果]取样5 g时,该法对克伦特罗的最低检出限为0.034μg/kg,线性范围5~100 ng,不同含量水平加标回收率75%~93%。[结论]GC-MS/MS法具有检测快速、定性定量准确及灵敏度高的优点,可用于测定动物性食品中克伦特罗残留量。     

气相色谱-串联质谱法测定淡水鱼中氯霉素残留量

目的建立气相色谱-串联质谱法(GC-MS/MS)测定淡水鱼中氯霉素残留量的方法。方法称取混匀后的样品,加入内标D5-氯霉素,用乙酸乙酯提取,正己烷脱脂,硅胶固相萃取柱净化,N,O双三甲基硅烷三氟乙酰胺-1%三甲基氯硅烷(BSTFA-1%TMCS)硅烷化衍生,采用GC-MS/MS分析,选择反应监测(SRM)方式测定。结果氯霉素浓度为0.20μg/L~20μg/L,相关系数为0.999 6,相对标准偏差为1.58%~3.30%(n=7),加标回收率为80.0%~107.2%(n=3),方法检出限为0.015μg/kg。结论方法稳定、灵敏度高,选择性好,适用于氯霉素残留量的分析。     

超高效液相色谱联用三重四极杆质谱法同时测定蜂蜜中氯霉素、甲硝唑和林可霉素

目的建立快速同时测定蜂蜜中氯霉素、甲硝唑和林可霉素残留量的超高效液相色谱联用三重四极杆质谱法。方法蜂蜜样品在pH=10下经乙酸乙酯萃取净化,以甲醇和0.1%氨水作为流动相进行梯度洗脱,在Acquity BEH C18(2.1 mm×50 mm,1.7μm)色谱柱上实现分离,采用电喷雾正负离子多反应监测模式扫描采集,稳定同位素稀释法测定氯霉素、甲硝唑和林可霉素的残留量。结果氯霉素在0.10～10.00μg/L、甲硝唑和林可霉素在0.05～10μg/L浓度范围内,呈线性关系,相关系数0.999 0;氯霉素的检出限(LOD)和定量限(LOQ)分别为0.03μg/kg和0.10μg/kg,甲硝唑和林可霉素的LOD均为0.02μg/kg,LOQ均为0.05μg/kg;在蜂蜜中分别添加0.10μg/kg、0.30μg/kg和9.00μg/kg的氯霉素,各0.05μg/kg、0.3μg/kg和9.00μg/kg的甲硝唑和林可霉素,加标回收率为98.1%～110.0%,相对标准偏差(RSD)为1.4%～17.0%(n=6);6份市售蜂蜜样品中有1份检出林可霉素,含量为0.57μg/kg,其余样品均未检出。结论所建实验方法适合于蜂蜜中氯霉素、甲硝唑和林可霉素残留量的同时测定,具有灵敏、准确、简便的特点,可用于食品安全风险监测实际样品的测定。     

固相萃取-超高效液相色谱-串联质谱法同时测定蜂蜜样品中氯霉素和甲硝唑

目的探讨建立固相萃取-超高效液相色谱串联质谱法同时检测蜂蜜样品中氯霉素(CAP)和甲硝唑(MNZ)残留量的方法。方法蜂蜜样品中氯霉素和甲硝唑采用优化的固相萃取方法提取,通过超高效液相色谱分离后,利用质谱正负离子切换模式同步测定合肥市本地25份蜂蜜样品中氯霉素和甲硝唑,以氘代同位素为内标,内标法定量,并分别添加低、中、高浓度标准液,测试精密度和回收率。结果该方法线性良好,相关系数(r)0.9992,当取样量为5.0 g时,氯霉素和甲硝唑的检出限(LOD)均为0.001μg/kg,3种浓度水平的加标回收率和相对标准偏差(RSD)分别在93.6%~105.0%之间和2.2%~7.6%之间。结论固相萃取-超高效液相色谱串联质谱法灵敏度高、重现性好,能满足蜂蜜样品中氯霉素和甲硝唑残留量的快速筛查与检测。     

凝胶色谱净化联合气相色谱串联质谱法同位素内标法测定茶叶中9,10-蒽醌

目的建立GPC-GC-MS/MS、同位素内标法测定茶叶中9,10-蒽醌的方法。方法称取经均质混匀处理后的茶叶样品,加入一定量d8-蒽醌同位素内标,经环己烷-乙酸乙酯(1∶1,V/V)混合溶剂提取,GPC净化、减压浓缩后,经Agilent DB-5MS(30 m×0.25 mm,0.25μm)色谱柱分离,GC-MS/MS测定,采用MRM多反应监测模式扫描,以保留时间、定性定量离子对的比率定性,内标法定量。结果该方法的线性范围为10μg/L~200μg/L,线性相关系数(r)=0.999;检出限和定量限分别为0.003 mg/kg、0.01 mg/kg;该方法的加标回收率为92.2%~95.5%,加标回收试验的精密度为2.70%~18.80%。结论该方法定性准确、灵敏度高、线性范围宽、准确度好、精密度高,能满足对茶叶中9,10-蒽醌的定性定量检测;GPC净化茶叶样品,操作简单,适于批量操作。     

福建市售薏苡仁常见真菌毒素污染状况研究

目的建立同位素内标稀释超高效液相色谱-串联质谱(UPLC/MS/MS)快速测定真菌毒素的方法,了解福建市售薏苡仁中常见真菌毒素污染状况。方法粉碎均匀的薏苡仁经提取、离心、稀释后,加入同位素内标以校正基质干扰,用UPLC/MS/MS测定。用该法检测2015—2017年采自福建省农贸市场、超市等销售的薏苡仁50份。结果建立了同位素内标稀释UPLC/MS/MS快速测定真菌毒素残留的方法,本法灵敏度高、操作简单,可满足检测要求。50份薏苡仁16种常见真菌毒素污染情况分析结果,发现玉米赤霉烯酮和脱氧雪腐镰刀菌烯醇是主要的污染指标,检出率分别为34.0%和30.0%。参考GB 2761-2017规定,保质期内薏苡仁中玉米赤霉烯酮的超标率仅4%(2/50)。结论本研究所建立的同位素内标稀释超高效液相色谱-串联质谱(UPLC/MS/MS)法,测定快速、灵敏度高、操作简单,能满足真菌毒素的检测要求;应加强食品中真菌毒素污染情况监测,对消费量小的薏苡仁食品也需加强管理。     

超高效液相色谱-串联质谱法测定鸡胗和鸡肝中氯霉素残留

目的 建立测定鸡胗、鸡肝中氯霉素残留的超高效液相色谱-串联质谱(UPLC-MS/MS)分析方法.方法 样品经乙酸乙酯提取,正己烷净化后,用UPLC-MS/MS在多反应监测(MRM)模式下进行检测,同位素内标法定量.结果 氯霉素在0.10 ng/ml～10.00ng/ml呈现良好的线性关系,相关系数＞0.997,检出限为...     

高效液相色谱-串联质谱法同时测定蜂蜜中氯霉素和甲硝唑及残留结果分析

目的 建立同时测定蜂蜜中氯霉素和甲硝唑的高效液相色谱-串联质谱法（液质法）,并分析2019年河南省市售蜂蜜中氯霉素和甲硝唑残留情况,提供一种快速高效检测方法,为监管部门制定政策及国家卫生标准限值提供数据支持。方法 采集2019年河南省18个地市的蜂蜜样品444份,采用液质法检测氯霉素和甲硝唑残留,并对残留结果进行分析。结果 甲硝唑检出范围为0.25～3.79μg/kg,检出率2.93%;氯霉素检出范围为0.25～1.64μg/kg,检出率0.68%,甲硝唑检出率高于氯霉素,但氯霉素最大测定值高于甲硝唑,两种抗生素均为独立检出。散装蜂蜜检出率高于定型包装蜂蜜,百花蜂蜜检出率最高,为5.7%;枣花蜂蜜次之,为4.6%;桂花蜂蜜未检出。结论 液质法同时测定蜂蜜中氯霉素和甲硝唑快速高效,残留结果表明河南省内市售蜂蜜中存在甲硝唑和氯霉素的污染,建议对养蜂过程中的违规滥用药物问题进行持续监测,相关部门应引导蜂农养殖生产,避免产品质量出现问题。     

同位素稀释-超高效液相色谱-串联质谱法测定蜂蜜中氯霉素及5种硝基咪唑

目的 建立同位素稀释-超高效液相色谱-串联质谱法测定蜂蜜中氯霉素及5种硝基咪唑的方法。方法 样品经水溶解后，乙酸乙酯提取，离心后取上层清液氮吹至近干，用甲醇水(10:90,v/v)溶液溶解后过0.22μm滤膜上机，以Acquity BEH C18柱(100 mm×2.1 mm, 1.7μm)为分离柱，用乙腈和0.1%甲酸水溶液为流动相，分段多反应监测模式采集，氯霉素采用负离子模式，5种硝基咪唑类化合物使用正离子模式，内标标准曲线法定量。结果 6种待测物在0.07～5.0 ng/ml内线性相关系数(r)大于0.999,方法检出限为0.01～0.04μg/kg,定量限为0.03～0.12μg/kg,平均回收率在90.7%～103.3%之间，相对标准偏差(RSD)在1.1%～7.3%之间。结论 本方法便捷、快速、准确，适用于蜂蜜中氯霉素和5种硝基咪唑残留量的快速准确测定。     

气相色谱-三重四级杆质谱法测定有机溶剂清洗剂中正己烷、苯、三氯乙烯

目的 建立有机溶剂清洗剂中正己烷、苯、三氯乙烯测定的气相色谱-三重四级杆质谱法(GC-MS/MS)。方法 样品用二硫化碳稀释，DB-5ms色谱柱分离，用GC-MS/MS在多反应监测模式(MRM)下测定。结果 正己烷、苯、三氯乙烯在0～10 mg/L范围内线性关系良好，检出限分别为0.072、0.36、0.063μg/L,批内、批间相对标准偏差(RSD)为2.7%～5.7%和4.7%～9.2%,加标回收率为84.0%～109.0%。结论 该方法适用于有机溶剂清洗剂中正己烷、苯、三氯乙烯的测定。     

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.