Ion mobility spectrometry for the detection of sodium saccharin and trace maleic acid in beverages

目的利用电喷雾-高效离子迁移谱(ESI-HPIMS)对饮料中常见的甜味剂糖精钠和有可能残存的痕量马来酸进行检测。方法通过在饮料中加入糖精钠和马来酸标准品来模拟添加剂存留情况,添加后的饮料经简单的稀释,过滤等前处理,直接进样即可测定。结果研究结果表明,仪器对糖精钠和马来酸标准品的灵敏度达到了10~(-10)数量级,最低检出限为0.1 ng/μl,6组平行数据的相对标准偏差(rSd)在1.2%~7.2%,线性相关系数均达到了r~2大于0.99,单次测量时间低于10 S。结论实现了糖精钠和痕量马来酸的快速分析检测。Objective Saccharin sodium and possible remaining maleic acid in beverages were detected by high performance ion mobility spectrometry with direct electrospray ionization(ESI-HPIMS).Methods By adding saccharin sodium and maleic acid standards into beverages to simulate real situation,the beverages were diluted,filtered,samples were injected into IMS directly.Results The research showed that the sensitivity of the instrument for saccharin sodium and maleic acid could reach 10-10 with detection of minimum standard 0.1 ng/μL,the relative standard deviation(RSD) of 6 parallel data was in the range of 1.2%~7.2%,with linear correlation coefficients r~2>0.99.The single detection time was less than 10 s.Conclusion This method can achieve a rapid analysis of sodium saccharin and trace maleic acid.国家质检总局科研项目(2014IK111)~

DETERMINATION OF TERBUFOS RESIDUES IN FOOD AND ENVIREMENT SAMPLES BY GC/GC-MS

建立在食品及环境样品中特丁硫磷残留量的气相色谱检测及气质联用确证法。样品采用乙酸乙酯提取、活性炭-酸性氧化铝复合小柱净化,丙酮-正己烷混合溶液(体积比为1∶9)洗脱,样液浓缩后经GC-FPD检测,外标法定量,GC-MS定性。GC-FPD法分析时,特丁硫磷在不同样品、不同水平的加标回收率为74.5%~103.3%,RSD为2.1%~11.7%(n=5),方法的检出限为0.001 mg/kg。气质联用法确证时,特丁硫磷的SIM离子为186、231(Q,100)、288。A method for the determination of terbufos residue in food and environment samples was developed.The GC-FPD was used as quantitative detection system,and positive sample was confirmed by GC-MS with SIM mode.Terbufos was extracted with ethyl acetate and eluted with acetone/n-hexane(volume ratio was 1∶9).A SPE column(ENVI-Carb 0.25 g,3 mL) with 0.5 g acid aluminum oxide on the top of the cartridge was used for purification.The recoveries of terbufos in different samples ranged from 74.5% to 103.3% with relative standard deviations ranging from 2.1% to 11.7%(n=5).Under the proposed conditions,the detection limit was 0.001 mg/kg for FPD.When terbufos was confirmed by GC-MS,186,231(Q) and 288 were selected as the SIM ions.厦门市科技计划项目(3502Z20072003);; 厦门出入境检验检疫局科技计划项目(2006XK03

Transfer of drug resistance plasmids from Escherichia coli to pathogenic vibrio

用混合培养法进行耐药质粒从大肠杆菌 (Escherichiacoli)向病原弧菌转移研究 ,结果表明 ,耐药质粒 pBR322和 pBR325可以从大肠杆菌向病原弧菌转移。在混合培养30min后 ,部分弧菌获得耐药质粒 ,质粒的转化率随着培养时间的延长而增大 ;混合培养24h后 ,转化率分别提高至4.62×10-6～1.18×10-5。耐药质粒 pBR322和 pBR325在2株病原弧菌细胞内能较为稳定地遗传 ,在培养初期 (0～1h) ,均未出现质粒丢失 ,随着培养时间的延长 ,有少量细胞因丢失耐药质粒而表现出对药物的敏感性 ;培养72h后 ,质粒 pBR322和 pBR325在副溶血弧菌(Vibrioparahaemolyticus)中的丢失率分别为10 %和9% ,溶藻弧菌(Vibrioalginolyticus)中2种质粒的丢失率分别为22%和19 %。细菌的药敏试验表明不同菌株在获得耐药质粒后对特定药物的抗性大大增强 ,但不同菌株的耐药水平有所不同 ,说明耐药质粒在不同菌株中的表达水平有所不同。The transfer of drug-resistant plasmid from Escherichia coli to pathogenic vibrios was studied by mixed culturing.Results showed that plasmid pBR322and pBR325could be transferred from E.coli to pathogenic vibrios.Some tested vibrio could be obtained plasmid within30min of mixed culturing.The transfer rate of plasmid increased with inˉcreasing culture time at24h the transfer rate was4.62×10 -6 ～1.18×10 -5 .Drug-resistant plasmid pBR322and pBR325were in pathogenic vibrio.In the initial stages of culture,no plasmid was lost,but as the culture time increased,some vibrio would lose plasmid and became sensitive to antibiotic.72h after culture,plasmids pBR322and pBR325lost in V.parahaemolyticus were10%and9%respectively,while in V.alginolyticus,22%and19%was lost.Bacterial drug-resistance level increased significantly after plasmid was obtained,but variety was seen between different bacteria indicating the expression level of drug-resistant plasmid varied.国家高技术研究发展计划 (863计划 )(819-02-12

Detection of the Vibrio alginolyticus LPS of Pseudosciaena crocea by indirect ELISA

用酚 水法从20dm3溶藻弧菌培养液中分离得到脂多糖(LPS)97.6mg,以0.5mg cm3的LPS溶液通过耳缘静脉注射免疫实验兔,经过3次加强注射后从颈动脉放血制备抗血清.该抗血清的效价为1∶2560,对副溶血弧菌等10株细菌的交叉反应效价都较低.用免疫吸附过滤法去除血清中的非特异性成分.用吸附后的抗血清进行溶藻弧菌间接ELISA检测,其检测限为97×104个 cm3.以ELISA进行大黄鱼体内溶藻弧菌检测.结果表明:用LPS抗血清可以较为灵敏地检测大黄鱼体内的溶藻弧菌,该方法不仅可以用于诊断大黄鱼的溶藻弧菌病,也可以检测无病症带菌大黄鱼.97.6mg lipopolysaccharide(LPS) were obtained by phenol-watermethod from 20dm~3 suspension of Vibrio alginolyticus. 0.5mg/cm~3 LPS were injected into rabbits for the sake of making anti-serum. The titer of anti-serum was 1∶2 560. The non-special component in the serum was removed by absorption. Serum after absorption was used for indirect ELISA detection. The detecting limit of V.alginolyticus was 9.7×10~4ind/cm~3. By using indirect ELISA of anti-LPS serum to detect V.alginolyticus in Pseudosciaena crocea, the results indicated that ELISA method could beused not only to diagnose the clinically diseased P.crocea, but also to recognize pathogenic bacteria carrying P.crocea.国家高技术研究发展计划(863计划)资助(863 819 02 12;2001AA635070

JUNO Sensitivity on Proton Decay p→νˉK+p\to \bar\nu K^+ Searches

The Jiangmen Underground Neutrino Observatory (JUNO) is a large liquid scintillator detector designed to explore many topics in fundamental physics. In this paper, the potential on searching for proton decay in $p\to \bar\nu K^+$ mode with JUNO is investigated.The kaon and its decay particles feature a clear three-fold coincidence signature that results in a high efficiency for identification. Moreover, the excellent energy resolution of JUNO permits to suppress the sizable background caused by other delayed signals. Based on these advantages, the detection efficiency for the proton decay via $p\to \bar\nu K^+$ is 36.9% with a background level of 0.2 events after 10 years of data taking. The estimated sensitivity based on 200 kton-years exposure is $9.6 \times 10^{33}$ years, competitive with the current best limits on the proton lifetime in this channel