超高效液相色谱-串联质谱法测定饮料中的4种环境类雌激素

目的建立超高效液相色谱-串联质谱(ultra performance liquid chromatography-tandem mass spectrometry,UPLC-MS/MS)测定饮料中双酚A(bisphenol A,BPA)、双酚S(bisphenol S,BPS)、辛基酚(octylphenol,OP)和壬基酚(nonylphenol,NP)残留量的分析方法。方法样品经过HLB固相萃取柱净化后,用ZORBAX SB-Aq柱(3.0 mm×100 mm,1.8μm)分离,以甲醇和5 mmol/L乙酸铵溶液作为流动相进行梯度洗脱,电喷雾负离子模式(ESI-)电离,多反应监测模式(multiple reaction monitoring,MRM)进行检测。结果 BPA、BPS在2~100μg/L范围内线性关系良好(r0.999),方法的检出限(S/N=3)为0.3、0.01μg/L,在0.25、2、8μg/L添加水平的回收率分别为78.6%~88.0%,相对标准偏差(n=6)为1.1%~6.0%;OP、NP在10~500μg/L范围内线性关系良好(r0.999),方法的检出限(S/N=3)为0.7、0.9μg/L,在1.25、10、40μg/kg添加水平的回收率分别为85.5%~107%,相对标准偏差(n=6)为2.1%~6.6%。结论该方法简单、灵敏、准确可靠,适用于饮料中BPA、BPS、OP和NP等环境类雌激素的测定。     

超高效液相色谱-串联质谱法测定大豆中3种异黄酮素

目的建立超高效液相色谱-串联质谱法测定大豆中金雀异黄素(genistein)、大豆苷元(daidzein)和黄豆黄素(glycitein)的含量。方法样品经过乙醇-水(3:1,V:V)提取,用AcquityUPLC?HSST3柱(3.0mm×150mm,1.8μm)分离,以甲醇和0.1%甲酸溶液作为流动相进行梯度洗脱,电喷雾负离子模式(electrospray ionization, ESI-)电离,多反应监测模式(multiple reaction monitoring mode, MRM)进行检测。结果金雀异黄素、大豆苷元和黄豆黄素在2.0～200μg/L范围内线性关系良好(r20.999),方法的检出限分别为0.5、0.4、0.1 mg/kg,在2.5、10.0、40.0 mg/kg添加水平的平均回收率为79.3%～107%,相对标准偏差(n=6)为1.3%～6.8%。结论方法简单、灵敏、准确可靠,适用于大豆中金雀异黄素、大豆苷元和黄豆黄素等3种异黄酮素含量的测定。     

The industrial robot in a flexible manufacturing system: State of the art and prospects

The actual situation of the industrial robots is described here. A comparison of the density in different countries gives an idea of the importance of these machines. The situation in Germany and especially in assembly automation is described more in detail. The results of a study of assembly automation are described as well as the necessity for assembly-oriented product design.     

320份市售熟肉制品的微生物检验结果分析

目的了解市售熟肉制品被微生物污染的状况,为食源性疾病的预防和控制提供科学依据。方法一年内分四季抽取320份熟肉制品,依照国家标准进行检验和评价分析。结果共检熟肉制品320份(城区160份,乡镇160份),合格130份,总合格率为40.6%;菌落总数合格193份,合格率60.3%;大肠菌群合格149份,合格率46.6%;检出致病菌和条件致病菌33份,检出率10.3%。结论中山市市售熟肉制品被微生物污染的程度较为严重,总合格率偏低,不合格主要是大肠菌群。检出致病菌和条件致病菌,提示要警惕熟肉制品引发食物中毒、食源性疾病。     

超高效液相色谱-串联质谱法测定大豆中异黄酮素含量

目的 以染料木黄酮、大豆苷元和黄豆黄素的含量为指标,建立超高效液相色谱-串联质谱测定大豆中异黄酮素总量的方法。方法 样品用乙醇-水(3+1,V/V)提取,经过β-葡萄糖苷酶水解后,用Acquity UPLC?BEH C18柱(2.1 mm×100 mm, 1.7μm)分离,以甲醇和0.1%甲酸溶液(含5 mmol/L乙酸铵)作为流动相进行梯度洗脱,电喷雾负离子模式(ESI-)电离,多反应监测模式进行检测。结果 染料木黄酮、大豆苷元在5.0～500μg/L范围内线性关系良好(r>0.995),方法的检出限分别为2.7、4.0 mg/kg,在300.0、600.0、1 200 mg/kg添加水平的平均回收率为89.4%～102.2%,相对标准偏差(n=6)为1.5%～4.6%;黄豆黄素在0.5～50.0μg/L范围内线性关系良好(r>0.995),方法的检出限为0.6 mg/kg,在30.0、60.0、120.0 mg/kg添加水平的平均回收率为85.7%～104.0%,相对标准偏差(n=6)为1.3%～2.8%。结论 该方法简单、灵敏、准确可靠,适用于大豆中异黄酮素含量的测定...     

Reduction of Escherichia coli O157, Listeria monocytogenes and Salmonella enterica sv. Typhimurium populations on fresh-cut bell pepper using gaseous ozone

Bacterial contamination is the main cause of food poisoning which can lead to diarrhoea, abdominal cramp, vomiting as well as death. Bacterial contamination can potentially be controlled by application of gaseous ozone due to its antibacterial activity. Therefore, the objective of this study was to investigate the efficacy of gaseous ozone for reducing food-borne pathogens such as Escherichia coli O157, Listeria monocytogenes and Salmonella enterica sv. Typhimurium on fresh-cut bell pepper. Efficacy of gaseous ozone to reduce bacterial populations was investigated in vitro and in vivo. Results showed that optimum effect of ozone on reducing bacterial populations was achieved with short term exposures of less than 6 h. Ozone reduced the bacterial population by disrupting bacterial cell structure, which lead to cellular death. Results also showed that bacterial cells have different resistance to ozone where ozone was more effective against L. monocytogenes, followed by E. coli O157 and Salmonella Typhimurium. Optimal reduction of the bacterial population on fresh-cut bell pepper was achieved with exposure to 9 ppm ozone for 6 h. This treatment reduced 2.89, 2.56 and 3.06 log of E. coli O157, Salmonella Typhimurium and L. monocytogenes populations, respectively. In conclusion, exposure to 9 ppm ozone for 6 h helps in reducing food-borne pathogen on fresh-cut bell pepper and has high potential to be an alternative sanitization treatment to reduce pathogen population on fruit.     

全自动固相萃取-超高效液相色谱-串联质谱法测定鸡肉中的金刚烷胺和利巴韦林

目的建立全自动固相萃取-超高效液相色谱-串联质谱法(ultra performance liquid chromatographytandem mass spectrometry,UPLC-MS/MS)同时测定鸡肉中金刚烷胺和利巴韦林含量的分析方法。方法样品加入同位素内标后用三氯乙酸和乙酸铵缓冲液提取,经PBA/PCX复合固相萃取柱净化后,用Acquity UPLC~HSS T3柱(3.0 mm×150 mm,1.8μm)分离,以乙腈和0.2%甲酸作为流动相进行梯度洗脱,电喷雾正离子模式(ESI+)电离,多反应监测模式(multiple reaction monitoring,MRM)进行检测。结果金刚烷胺在0.2~10 ng/mL范围内线性关系良好,方法的检出限为(S/N=3)0.02μg/kg,在0.6、2.4和12μg/kg添加水平的平均回收率分别为92.2%、99.2%和99.2%,相对标准偏差(n=6)为6.2%、4.3%和1.5%。利巴韦林在1.0~50 ng/mL范围内线性关系良好,方法的检出限为(S/N=3)0.1μg/kg,在3.0、12和60μg/kg添加水平的平均回收率分别为99.0%、97.5%和97.2%,相对标准偏差(n=6)为4.9%、2.8%和1.4%。结论该方法简单、灵敏、准确可靠,适用于鸡肉中金刚烷胺和利巴韦林含量的同时测定。