固相萃取-高效液相色谱法测定畜禽肉中四环素类抗生素残留

目的:建立采用固相萃取技术净化样品,高效液相色谱-紫外检测器同时测定畜禽肉中土霉素、四环素和金霉素3种四环素类抗生素残留的方法。方法:样品经过匀浆、旋涡、超声、离心后,取上清液经Wa-ters Oasis HLB萃取柱净化,净化液经氮吹仪浓缩后进样,色谱柱采用Agilent Eclipse XDB-C18 150×4.6 mm,5μm,流动相为(0.01 mol/L磷酸二氢钠∶乙腈∶甲醇=70∶20∶10,流速0.8 ml/min,检测波长为355 nm和270 nm,柱温30℃,进样量50μl进行检测。结果:样品平均回收率为82.0%～98.4%,RSD为0.8%～3.2%,线性范围为0.02μg/ml～10μg/ml,相关系数为0.99998～0.99999,最低检出浓度为土霉素0.4μg/kg,四环素0.4μg/kg,金霉素0.8μg/kg。结论:建立的方法用于同时测定畜禽肉中土霉素、四环素和金霉素3种四环素类抗生素残留灵敏度高,分离度好,回收率高,适合于日常检测工作。     

高效液相色谱法同时测定动物组织中四种抗生素残留量的研究

为了快速、简便、灵敏地检测动物组织中土霉素、四环素、金霉素、氯霉素残留 ,建立了高效液相色谱分析法。样品用高氯酸沉淀蛋白质 ,超声波提取 ,高效液相色谱法同时测定四种抗生素。色谱柱为SUPELCODiscoveryC185 μm2 5 0× 4.6mm ,流动相为 0 .0 1mol/L磷酸二氢钠 0 .0 0 1mol/LEDTA :甲醇 =60 :40 (V/V ,pH =2 .0 ) ,流速为 0 .8ml/min ,检测波长为 2 68nm。本方法的最低检出浓度分别为 :土霉素 (0 .18mg/kg)、四环素 (0 .2 5mg/kg)、金霉素 (0 .43mg/kg)、氯霉素(0 .10mg/kg) ,标准曲线线性良好 ,其回归方程及相关系数r分别为土霉素 :y =5 6.3 2 15x -0 .90 0 4,r =0 .9999;四环素 :y =42 83 45x -1.14 84,r=0 .9999;金霉素 :y =2 3 .0 0 97x -0 .963 0 ,r =0 .9999;氯霉素 :y =3 8.83 3 2x 0 .165 5 ,r =0 .9999,回收率在 93 %～ 10 1%之间 ,相对标准偏差小于 1.9%。     

UPLC-ESI-MS/MS检测畜、禽肉中土霉素、四环素、金霉素残留量

目的：建立超高效液相色谱-电喷雾串联四极杆质谱快速测定畜、禽肉中土霉素、四环素、金霉素的方法。方法：采用超高效液相色谱-电喷雾串联四极杆质谱仪,多离子反应监测（MRM）定量法,通过对试样净化预处理、色谱条件、质谱参数等的优化选择和方法回收率、精密度等的验证,建立了同步准确定量测定肉类食品中土霉素、四环素、金霉素的理想方法。结果：土霉素、四环素、金霉素的最低检出限（LOD）分别为0.1、0.1、0.5μg/kg,在5.0-80.0 ng/ml的线性范围内,相关系数r均大于0.99,回收率在82.6%-111%。结论：采用液相色谱-电喷雾串联四极杆质谱仪,可快速测定畜、禽肉样品中土霉素、四环素、金霉素含量,结果准确可靠,重复性好,灵敏度高。     

SPE-HPLC法同时测定水产品中四种抗生素残留的研究

目的 :为快速、简便、灵敏的检测水产品中土霉素、四环素、金霉素、氯霉素残留 ,建立了固相萃取(SPE) -高效液相色谱 (HPLC)分析法。方法 :样品高氯酸沉淀蛋白质 ,超声波提取 ,固相萃取 ,高效液相色谱法同时测定 4种抗生素。固相萃取小柱为ZORBAXSPEC18Cart,洗脱液为 5 0 %甲醇水 ;色谱柱为SUPELCODiscoveryC185 μm 2 5 0× 4 . 6mm ,流动相为 0 . 0 1mol/L　磷酸二氢钠 +0 . 0 0 1mol/L　EDTA :甲醇 =6 0∶4 0 (V/V ,pH =2. 0 ) ,流速为 0 .8ml/min ,检测波长为 2 6 8nm。结果 :本方法的最低检出浓度分别为 :土霉素 (0. 0 18mg/kg)、四环素 (0 . 0 2 5mg/kg)、金霉素(0 .0 4 3mg/kg)、氯霉素 (0 . 0 10mg/kg)、标准曲线线性良好 ,其回归方程及相关系数r分别为土霉素 :y =5 6 . 32 15x -0 . 90 0 4 ,r=0 .9999;四环素 :y =4 2 .8345x - 1 .14 84 ,r=0 .9999;金霉素 :y =2 3 0 0 97x - 0 . 96 30 ,r =0 . 9999;氯霉素 :y=38 .8332x+0 . 16 5 5 ,r=0 . 9999,回收率在 93%～ 10 1%之间 ,相对标准偏差小于 1 .9%。结论 :以超声波萃取 ,经固相柱净化、用二极管阵列检测器是一种快速、灵敏、简便的测定水产品中抗生素残留的高效液相色谱方法。     

典型抗生素对羊角月牙藻的生长抑制及其联合毒性

目的 研究两种使用量较大的头孢类抗生素(头孢氨苄、头孢拉定)及其主要降解产物7-氨基头孢霉烷酸(7-ACA)和四环素类药物(四环素和金霉素)对羊角月牙藻(Selenastrum capricornutum)生长的作用及其联合毒性.方法 将5种物质分别暴露于羊角月牙藻,设置5个浓度梯度(四环素和金霉素均为0.25～4 μg,/ml,头孢氨苄、头孢拉定均为0.1～1 000 μg/ml,7-ACA为60～960 μg/ml)及空白对照;同时,依据毒性单位法设计四环素+金霉素及四环素+7-ACA的联合毒性实验,5个浓度梯度的混合物总毒性单位(TU)为0.2、0.4、0.8、1.6和3.2 TU,培养72 h后测定藻液密度并计算相应抑制率和半数抑制浓度(IC50值).结果 羊角月牙藻的72 h-IC50分别为:四环素0.50 μg/ml、金霉素0.47 μg/ml、7-ACA 775.6μg/ml.头孢拉定在测试浓度范围(0.1～1 000 μg/ml)的抑制率均为负值;头孢氨苄在低浓度(0.1、1和10μg/ml)时的抑制率为负值,但在高浓度(100和1 000 μg/ml)下产生抑制作用;且当头孢氨苄浓度为1 000 μg/ml时,抑制率小于50％.因而头孢拉定和头孢氨苄在所测试范围内不能计算出72 h-IC50值.四环素+金霉素组的IC50值为0.99 TU;而四环素+7-ACA组的IC50值为1.5 TU.结论 四环素类药物对羊角月牙藻的生长产生抑制作用;但头孢拉定在测试浓度却刺激羊角月牙藻的生长;头孢氨苄和7-ACA对羊角月牙藻的作用存在明显hormesis现象,且7-ACA的毒性明显高于其母体.四环素和金霉素的联合毒性表现为相加作用,而四环素+7-ACA的联合毒性则为拮抗作用.     

凝胶渗透色谱净化-高效液相色谱法测定动物源性食品中四环素类药物残留

目的:建立凝胶渗透色谱净化-高效液相色谱法同时测定动物源性食品中四环素、土霉素、金霉素药物残留的方法。方法:样品用乙腈提取,提取液经Pharmadex LH-20凝胶柱(15 mm i.d×450 mm)净化,用1%乙酸甲醇洗脱。采用Agilent TC-C18柱(4.6 mm i.d×250 mm,5μm)分离,以乙腈-0.1%三氟乙酸(18:82,v/v)洗脱,流速为1.5 ml/min,检测波长为360 nm。结果:四环素、土霉素药物在0.02~1.0 mg/L范围内,金霉素在0.04~2.0 mg/L范围内有良好的线性关系(r0.999),检测限为11~33μg/kg,平均加标回收率为51.9%~95.2%,相对标准偏差3.4%~6.7%。结论:方法快速、简单,可应用于食品中四环素类药物残留量的检测。     

高效液相色谱法检测水产品中抗生素药物残留

目的:建立了同时检测水产品中土霉素、四环素、氯霉素、金霉素残留量的检测方法。方法:采用高效液相色谱法,利用Mellvmince-EDTA缓冲溶液提取,ODS-C18固相萃取柱净化,乙腈-磷酸二氢钠为流动相,以350 nm为检测波长,0.85 ml/min流速,梯度洗脱。结果:本方法在0.1μg/ml～2.0μg/ml范围内线性良好,相关系数在0.9991～0.9996之间,检出限在18μg/kg～32μg/kg之间,精密度RSD在2.12%～4.59%之间,回收率在88%～94%之间。结论:方法简单、快速,灵敏度高,定量准确、毒性低,对环境污染少等优点。     

杭州城区动物性食品中四环素类抗生素残留调查

目的了解杭州城区市售动物性食品中四环素、金霉素、土霉素和强力霉素的残留水平,为动物性食品的质量安全监管提供依据。方法 2018年从杭州市西湖区、江干区、下城区和滨江区的农贸市场、超市和个体自营店采集鸡肉、鸡蛋、河/湖虾和淡水小龙虾共66份,按照GB/T 21317—2007 《动物源性食品中四环素类兽药残留量检测方法液相色谱-质谱/质谱法与高效液相色谱法》检测四环素、金霉素、土霉素和强力霉素残留水平。结果 66份样品检出四环素类抗生素残留样品13份,总检出率为19.70%。除鸡蛋外,其他3类样品均检出四环素类抗生素残留,检出强力霉素11份,检出率为16.67%,检出浓度为0.87～7.36μg/kg;检出土霉素6份,检出率为9.09%,检出浓度为1.99～12.90μg/kg;四环素和金霉素均未检出。鸡肉样品中强力霉素和土霉素的检出率分别为47.06%和17.65%;河/湖虾样品中强力霉素和土霉素的检出率均为10.71%。西湖区、江干区、下城区和滨江区样品的四环素类抗生素检出率分别为28.57%、22.22%、20.00%和7.69%,差异无统计学意义(P0.05)。来自超市、农贸市场和自营商店样品的四环素类抗生素检出率分别为23.08%、17.65%和16.67%,差异无统计学意义(P0.05)。结论杭州城区市售鸡肉、河/湖虾和淡水小龙虾均有强力霉素和士霉素残留,需加强对养殖业合理用药的指导与监管。     

高效液相色谱法同时测定畜禽废水中4种四环素类抗生素

目的利用高效液相色谱-二极管阵列检测器,建立同时检测畜禽废水中土霉素、四环素、金霉素、强力霉素的方法。方法选用Waters SunF ire C18色谱柱(250 mm×4.6 mm,5μm),乙腈-0.5%三氟乙酸(TFA)水溶液为流动相梯度洗脱,流速1.2ml/min,检测波长360nm,高效液相色谱仪测定。结果土霉素、四环素、金霉素和强力霉素4种抗生素质量浓度为0.1μg/ml~15.0μg/ml时有良好的线性关系,4种抗生素的检出限均为50ng/ml,方法回收率在83.82%~108.70%之间。结论高效液相色谱法方便、快速、准确,且重现性好,能够用于畜禽废水中四环素类抗生素的检测。     

高效液相色谱法测定化妆品中四种抗生素

目的:建立测定化妆品中抗生素含量的高效液相色谱检测方法。方法:样品经甲醇+0.1 mol/L盐酸=1+1的混合溶液提取,用HPLC-DAD进行分析检测,色谱条件为:色谱柱:Waters-AtlantisT3,4.6 mm×150 mm I.D.,粒径5μm;流动相:乙腈+0.02 mol/L磷酸二氢钾(含0.1%甲酸)=15+85;流速:1.0 ml/min;检测波长:218 nm。结果:氨苄西林浓度在25 mg/L～250 mg/L时,美满霉素、土霉素、四环素浓度在50 mg/L～500 mg/L时,工作曲线回归系数为0.999以上,平均回收率为85.6%～109.5%,精密度(RSD)为3.01%～7.74%,氨苄西林检出限为5 mg/L,美满霉素检出限为10 mg/L、土霉素检出限为10 mg/L、四环素检出限为15 mg/L。结论:该方法前处理简单,分离效果好,准确度高,能够满足测定化妆品中氨苄西林、美满霉素、土霉素、四环素的需要。     

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.     

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.     

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.     

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.