HPLC法同时快速测定饮料中12种添加剂

目的:采用变波长-反相高效液相色谱法,同时测定饮料中甜味剂(糖精钠、乙酰磺胺酸钾),防腐剂(苯甲酸、山梨酸),人工合成色素(柠檬黄、胭脂红、苋菜红、日落黄、亮蓝、赤藓红、诱惑红)及咖啡因.方法:以Agilent HC-C18柱(5μm,4.6 mm×150 mm)为分离柱,乙酸铵-甲醇为流动相,采用梯度洗脱,变换波长的方法进行检测.结果:12种组分完全分离,标准曲线线性良好,相关系数大于0.9999,回收率在88.9%～105%之间,相对标准偏差<5%.结论:该方法简便、快速,灵敏度高,分离度好,适用于饮料中12种食品添加剂的同时测定.     

高效液相色谱法同时快速测定食品中8种常用添加剂

目的建立梯度洗脱-反相高效液相色谱法同时测定食品中8种添加剂(柠檬黄、苋菜红、糖精钠、胭脂红、日落黄、苯甲酸、山梨酸、亮兰)的高效液相色谱方法。方法样品经前处理后用0.45μm微孔滤膜过滤后,以甲醇-0.02mol/L乙酸铵溶液(pH=5.0)梯度洗脱,二级管阵列(DAD)检测器:240 nm波长。流量1.0 ml/min,柱温:室温。结果线性关系好,回归系数均为0.999 9,回收率为96.0%~100.1%,相对标准偏差为0.4%~2.9%,检出限为0.01 mg/kg~0.06 mg/kg。,结论该法同时测定食品中8种添加剂成分,快速准确、重现性好,适合基层卫生单位快速检测。     

反相高效液相色谱梯度洗脱法测定乳饮料中9种食品添加剂

目的:建立反相高效液相色谱法同时测定乳饮料中9种食品添加剂的分析方法。方法:样品经甲醇处理后采用Gemini C18柱(250 mm×4.6 mm×5μm)以乙腈-三氟乙酸-乙酸铵为流动相进行梯度洗脱分离,紫外检测器测定,外标法定量。检测波长为210 nm,柱温30℃。结果:安赛蜜、糖精、咖啡因、阿斯巴甜、苯甲酸、山梨酸、脱氢乙酸和纽甜在5.0 mg/L～100.0 mg/L范围均具有良好的线性,甜菊糖苷在10.0 mg/L～200.0 mg/L范围具有良好的线性,9种待测物的回收率在93.2%～103.3%范围,RSD均小于6.0%,最低定量检出限在1.0 mg/kg～10 mg/kg范围。结论:该方法前处理简单,梯度洗脱分离效果和重现性好,具有快速、灵敏、简便、准确等优点,能满足实际工作的需要。     

超高效液相色谱法同时测定奶茶饮品中的10种添加剂

目的建立同时测定奶茶饮品中10种添加剂(咖啡因、茶碱、4种甜味剂及4种香味剂)的超高效液相色谱分析方法。方法奶茶饮品经乙醇-水(1∶1,V/V)超声提取,定容,上清液经离心过滤后进样分析。采用反相AcclaimTM RSLC120 C18柱(150 mm×2.1 mm,2.2μm)分离,以乙腈-0.02 mol/L乙酸铵水溶液(含0.25%乙酸)为流动相进行梯度洗脱,紫外检测。结果 10种添加剂的线性关系良好,相关系数为0.999 2~0.999 9;线性范围:茶碱、甘素、甲基香兰素、乙基麦芽酚为0.05 mg/L~50.0 mg/L,安赛蜜、糖精钠、咖啡因为0.20 mg/L~50.0 mg/L,香兰素、麦芽酚为0.30 mg/L~50.0 mg/L,纽甜为0.50 mg/L~50.0 mg/L;检出限为0.01 mg/L~0.15 mg/L;加标回收率为97.0%~104.6%,相对标准偏差为0.45%~3.36%。结论本方法简单、快速、结果准确,可用于同时测定奶茶饮品中常见的10种添加剂的检测。     

反相高效液相色谱法测定饮料中咖啡因含量

目的建立一种简单流动相洗脱的反相高效液相色谱法快速测定饮料中咖啡因含量。方法以甲醇-水-乙酸为流动相,对饮料进行简单的过滤处理后直接进样测定。结果标准曲线的回归方程为y=52.54635x+47.46411,相关系数r=0.99996;测定咖啡因保留时间的标准偏差为0.087 min,RSD为1.41%;浓度的标准偏差为2.22 mg/L,RSD为1.98%;测定结果的总体回收率在97.5%~98.1%之间;加标回收率在92.2%~95.9%之间。结论采用本法测定饮料中的咖啡因含量,具有结果准确、样品处理方法简便、流动相组成简单等优点,适合饮料中咖啡因的测定。     

液相色谱-串联质谱法同时测定饮料中的咖啡因、茶碱和可可碱

目的建立市售饮料中咖啡因、茶碱和可可碱的液相色谱-串联质谱法(LC-MS/MS)。方法将饮料用水稀释100倍后,采用三氯甲烷∶异丙醇(9∶1,V/V)进行提取,提取液经Allure PFP Propyl柱(100 mm×2.1 mm,5μm)分离,以5 mmol/L乙酸铵溶液(含5%甲醇、0.05%的甲酸)-甲醇为流动相进行梯度洗脱,采用电喷雾正离子化(ESI+)、多反应监测模式同时测定咖啡因、茶碱和可可碱。结果咖啡因、茶碱和可可碱在10 ng/ml^1000 ng/ml范围内方法的线性相关系数(r)均>0.9970,检出限为2 ng/ml^5 ng/ml,加标回收率均>60.68%,精密度均<14.41%。应用于实际市售饮料中,均检出咖啡因成分,部分饮品检出茶碱、可可碱成分。结论该方法简便、灵敏,可用于监测市售饮料中咖啡因、茶碱、可可碱的含量。     

饮料中11种添加剂的高效液相色谱测定法

目的研究用液相色谱法一次性测定饮料中苯甲酸、山梨酸、安赛蜜、糖精钠、阿斯巴甜、咖啡因、日落黄、柠檬黄、苋菜红、胭脂红、亮蓝的分析方法。方法利用高效液相色谱(HPLC)法梯度洗脱对11种饮料添加剂进行分离,定量测定。结果合成着色剂线性范围为2.5～25μg/ml,其他添加剂线性范围为10～100μg/ml,相关系数0.999 8～0.999 9。结论该方法一次分离11种添加剂,简便,快捷,适合含有其中几种添加剂的样品批量测定。     

饮料中6种添加剂超高效液相色谱测定

目的:建立饮料中6种食品添加剂的超高效液相色谱同时测定方法。方法:样品经乙腈去除蛋白后用水稀释,采用C18色谱柱,以乙酸铵缓冲液(0.02 mol/L)/甲醇为流动相,采用梯度洗脱分离,在230 nm波长下进行检测。结果:6种食品添加剂的加标回收率在90%~108%之间,相对标准偏差在1.0%~3.8%之间。阿斯巴甜在15μg/m l~100μg/m l范围具有良好的线性,安赛蜜、苯甲酸、山梨酸、糖精钠和咖啡因在1μg/m l~10μg/m l范围具有良好的线性,回归系数均大于0.999,最低定量限分别为,安赛蜜0.05 mg/L,苯甲酸0.05 mg/L,山梨酸0.02 mg/L,糖精钠0.1 mg/L,咖啡因0.1 mg/L,阿斯巴甜1.0 mg/L。结论:本方法简便、灵敏、重现性好,能满足饮料中6中添加剂的测定要求。     

固相萃取-高效液相色谱法同时测定饮料中10种食品添加剂

目的建立固相萃取-高效液相色谱法同时测定饮料中10种食品添加剂苯甲酸、山梨酸、糖精钠、柠檬黄、苋菜红、胭脂红、日落黄、赤藓红、亮蓝、诱惑红的方法。方法样品经固相萃取后,经色谱柱Waters sunfire C18(4.6 mm×250 mm,5μm)进行分离,流动相为甲醇-乙酸铵溶液进行梯度洗脱,柱温为30℃;进样量为10μl,流速为1.0 ml/min,检测波长为230 nm。结果 10种食品添加剂40 min内完全分离,最低检出限为0.08 mg/L~0.24 mg/L,在3个浓度水平下,加标回收率为87.8%~103.9%。相对标准偏差(RSD)为0.94%~5.41%。结论该方法简单、准确可靠,适用于饮料中10种食品添加剂的同时测定。     

反相高效液相色谱法同时测定海产品中11种食品添加剂

目的:建立反相高效液相色谱法同时测定海产品中11种添加剂。方法:30%乙腈溶液提取,采用synergy C18色谱柱(250×4.6 mm,5μm)梯度洗脱分离,变波长紫外检测器检测,外标法定量。结果:11种添加剂浓度在0～50 mg/L范围内线性关系良好,相关系数r=0.9999,检测限为0.0077 mg/L～0.045 mg/L,平均回收率均大于90%,相对标准偏差均小于5%。结论:方法便捷、灵敏、准确,适合海产品中多种添加剂的同时检测。     

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.