Residue Detection of Tetracyclines in Eggs by High Performance Liquid Chromatography

The study was aimed to establish the method of simultaneous detection of four kinds of tetracyclines,including oxytraoycline,tetracycline,chlortetracycline and doxyeycline in eggs by high performance liquid chromatography (HPLC).The eggs samples were detected with HPLC after through the procedure of extraction of 0.1 mol/L Na₂EDTA-Mcllvaine buffered solution,purification of Oasis MAX solid-phase extraction column,gradient elution of taking acetonitrile-0.01 mol/mL trifluoroacetic acid as mobile phase,separation with reverse liquid chromatography.The results showed that the calibration curves of four kinds of tetracyclines were linear correlated in the concentration range of 30 to 1 000 ng/g which the limits of detection was 10 ng/g and the limit of quantification was 50 ng/g.The average recoveries were 67.3% to 81.4%,relative standard deviations of intraday was 2.7% to 14.3%,relative standard deviations of inter-day was 0.9% to 5.0%.This mothod established in this study could simultaneously detect oxytetracycline,tetracycline,chlortetracycline and doxycycline drug residues in egg and it had high sensitivity,accuracy and precision.The method was rapid and simple to operate.     

嗜水气单胞菌对四环素类和氟喹诺酮类药物的耐药性研究

在离体条件下进行患病鱼体内分离的嗜水气单胞菌3个菌株对四环素类和氟喹诺酮类药物的耐药性获得、稳定性、保存条件和交叉耐药性研究.结果表明:分别在含有盐酸多西环素、盐酸四环素、诺氟沙星和左氧氟沙星的药物培养基中连续传代9次(在28℃条件下培养72 h为1代)后,四环素类对3个菌株的最小抑菌浓度上升倍数为8～32倍,氟喹诺酮...     

固相萃取-高效液相色谱法测定有机肥中四环素类抗生素药物残留

建立了固相萃取-高效液相色谱(SPE-HPLC)法测定有机肥中土霉素(OTC)、四环素(TC)和金霉素(CTC)3种四环素类抗生素残留的方法。肥料样品采用甲醇、EDTA和McIlvaine缓冲液的混合液(pH=7.2)为提取液,用强阴离子交换柱(SAX)-亲水亲脂萃取柱(HLB)串联进行纯化和富集。采用甲醇-乙腈-0.01mol/L草酸溶液为流动相,进行HPLC分析。3种抗生素的线性范围为0.10～20 mg/L,OTC、TC和CTC的检测限分别为0.03、0.03和0.05 mg/L。不同添加水平的样品加标回收率为64%～86%,RSD在4.14%～8.16%之间。该方法测定了上海市场上40种肥料,发现部分样品有四环素类抗生素的残留物。     

胶体金试纸条法和液相色谱-串联质谱法检测牛奶中四环素类药物残留比较

采用胶体金试纸条与液相色谱-串联质谱（LC-MS/MS）两种方法检测牛奶中残留的四环素类药物。结果表明：胶体金试纸条的检测限为四环素40μg/L、强力霉素40μg/L、金霉素40μg/L、土霉素80μg/L;LC-MS/MS法在牛奶中四环素、强力霉素、金霉素、土霉素的检测限为50μg/L。采用两种方法对实际样品检测,检测结果一致。与液相色谱-串联质谱法相比,胶体金试纸条具有操作简便、快速、直观的特点,可作为筛选法对样品进行定性筛查,LC-MS/MS法进行阳性样品的确证和精确定量。     

贵州省猪源大肠杆菌对四环素类药物的耐药性及耐药基因检测

为考察贵州省猪源大肠杆菌对四环素类抗菌药的耐药情况和耐药基因的流行情况,本试验采用微量肉汤稀释法测定783株分离于贵州省8个地区规模化养殖场的猪源大肠杆菌对6种四环素类药物的敏感性,并通过PCR方法检测其携带四环素耐药基因情况。结果显示,猪源大肠杆菌对土霉素、四环素、金霉素、多西环素、米诺环素和替加环素的耐药率分别为97.3%、97.6%、96.6%、89.3%、48.0%和34.2%;土霉素和四环素的耐药水平最高,其MIC₅₀分别为256 和128 μg/mL,而MIC₉₀均为512 μg/mL,四环素的耐药倍数高于土霉素;米诺环素和替加环素的耐药水平最低,其MIC₉₀分别为32和4 μg/mL,耐药倍数相同;耐药基因tetA、tetB、tetC、tetD和tetM的检出率分别为92.60%、41.50%、58.75%、58.62%和70.10%;耐药菌株中主要以tetA基因为主,且大多数以携带复合基因的形式存在;大肠杆菌对土霉素、四环素、金霉素、多西环素和米诺环素的耐药性分别与耐药基因tetB和tetM呈极显著相关（P<0.01）,tetD基因分别与对米诺环素和替加环素的耐药性呈极显著相关（P<0.01）。贵州省猪源大肠杆菌对四环素类药物的耐药情况十分普遍,尤其是四环素和土霉素,金霉素和强力霉素有高度耐药的趋势;外排泵是四环素类药物主要的耐药机制;在兽医临床上越来越严重的耐药情况与耐药基因的广泛存在有很大关系。     

反相高效液相色谱法测定鱼肉组织中四环素族抗生素残留量

建立了一种采用同相萃取-反相高效液相色谱法同时测定鱼肉中土霉素、四环素、金霉素的分析方法,即样品用McI-Vaine-EDTA溶液提取,C18小柱净化,流动相洗脱定容,选择355nm为检测波长进行检测,结果表明:土霉索、四环素、会霉素的检出限分别为0.02、0.03、0.04 mg/kg,方法相对标准偏差为2.95%～5.73%,平均回收率为80%～92%.     

猪肉中四环素类抗生素的固相萃取-液相色谱法测定

本文建立了猪肉中四环素类抗生素的高灵敏度测定方法,通过对实验条件的优化,采用固相萃取- 反相高效色谱法同时测定猪肉中的土霉素（oxytertracycline ）, 四环素（tetracycline ）,金霉素（chlorteracycline ）,去甲基金霉素（demeclocycline ）,脱氧土霉素（doxycycline） 五种抗生素残留量;土霉素,四环素,金霉素,脱氧土霉素, 去甲基金霉素的检出限分别为50,50,100, 100, 50ug/kg,方法相对标准偏差范围为3.7 %-8.9 % (n = 5) 平均回收率70 %-90 %。 关键词 ：固相萃取;反相高效液相色谱法;四环素类;猪肉     

中国西北地区膜下滴灌对棉田土壤CO2通量和浓度的影响

In northwestern China,there has been a change from traditional cultivation system (TC) with no mulching and flood irrigation to a more modern cultivation system (MC) using plastic film mulching with drip irrigation.A field study was conducted to compare soil CO 2 concentrations and soil surface CO 2 fluxes between TC and MC systems during a cotton growing season.CO 2 concentrations in the soil profile were higher in the MC system (3 107-9 212 μL L-1) than in the TC system (1 275-8 994 μL L-1) but the rate of CO 2 flux was lower in the MC system.Possible reasons for this included decreased gas diffusion and higher soil moisture due to the mulching cover in the MC system,and the consumption of soil CO2 by weathering reactions.Over the whole cotton growing season,accumulated rates of CO2 flux were 300 and 394 g C m-2 for the MC and TC systems,respectively.When agricultural practices were converted from traditional cultivation to a plastic film mulching system,soil CO 2 emissions could be reduced by approximately 100 g C m-2 year-1 in agricultural lands in arid and/or semi-arid areas of northern and northwestern China.     

ROSA法快速检测UHT奶中的四环素类和β-内酰胺类药物残留

主要探讨应用ROSA法同时快速检测UHT奶中的四环素类和β-内酰胺类药物残留。评价了ROSA法的灵敏度和特异性,验证了ROSA法的检测稳定性,10 min可出检测结果。     

鱼源温和气单胞菌对氨基糖苷类和四环素类抗生素的耐药性分析

为探究温和气单胞菌对氨基糖苷类和四环素类抗生素的耐药性,试验采用PCR法检测10株来源不同的鱼源温和气单胞菌对氨基糖苷类抗生素的4种耐药基因（aph（3'）-Ⅱa、ant（3″）-Ⅰa、aac（6'）-Ⅰb、aac（3）-Ⅱa）及四环素类抗生素的3种耐药基因（tetA、tetC、tetM）的表达情况,并利用K-B纸片扩散法对6种抗生素进行耐药表型分析。结果显示,10株温和气单胞菌对氨基糖苷类耐药基因aph（3'）-Ⅱa、ant（3″）-Ⅰa、aac（6'）-Ⅰb的检出率分别为20%、30%、20%,未检测出aac（3）-Ⅱa基因;对四环素类的耐药基因tetA、tetC、tetM的检出率分别为70%、20%、60%。K-B纸片扩散法结果显示,10株菌对四环素耐药率最高,对链霉素敏感,对庆大霉素、卡那霉素、多西环素、米诺环素高度敏感。结果表明,本次分离的温和气单胞菌对氨基糖苷类和四环素类抗生素具有一定的耐药性,为深入了解温和气单胞菌的耐药机制提供参考。