鸡肉鸡肝中20种磺胺类兽药残留的测定——QuEChERS-超高效液相色谱串联质谱法

笔者建立了一种同时测定鸡肉及鸡肝中20种磺胺类兽药残留的Qu ECh ERS-超高效液相色谱串联质谱检测方法。样品经1%的乙酸乙腈水溶液(20/80,V/V)提取,振荡离心后,取上清液于Qu ECh ERS净化管中净化,取净化液,浓缩至干,甲醇水溶液(甲醇∶水=1∶4)溶解残渣,过膜,待测。采用C18色谱柱(2.1 mm×100 mm,1.7μm)分离,以0.2%甲酸水溶液和0.2%甲酸乙腈溶液作为流动相进行梯度洗脱,UPLC-MS/MS法同时定性、定量测定鸡肉和鸡肝中20种磺胺类兽药残留。20种磺胺类兽药在0.5 ng/m L~80 ng/m L范围内线性关系良好,相关系数(r)均大于0.99μg/kg。以5μg/kg、10μg/kg和50μg/kg 3个浓度水平进行添加回收实验,20种磺胺类兽药的平均回收率在64.4%~108.0%之间,相对标准偏差为2.6%~19.0%,方法的定量限为5μg/kg。方法重现性、灵敏度高,分析时间短,确证能力强,适用于鸡肉及鸡肝中20种磺胺类兽药残留的同时检测。     

超高效液相色谱-串联质谱法同时检测鸡蛋中5种磺胺类药物和甲氧苄啶残留量

建立超高效液相色谱-串联质谱法(Ultrahigh-performance liquid chromatography-tandem mass spectrometry, UPLC-MS/MS)同时测定鸡蛋中5种磺胺类药物(磺胺甲恶唑、磺胺二甲嘧啶、磺胺间甲氧嘧啶、磺胺喹噁啉、磺胺二甲氧嘧啶)和甲氧苄啶的残留量的方法。样品经乙腈提取2次, 95%乙腈溶液进行溶解后,过Alumina B Cartridges柱,30%乙腈洗脱,滤膜过滤后滤液用于超高效液相色谱-串联质谱仪测定,外标基质标准曲线法定量。在0.5～100μg/kg的浓度范围内5种磺胺类药物和甲氧苄啶色谱峰面积与浓度呈良好线性相关,相关系数均大于0.99;方法检测限0.5μg/kg、定量限为1.0μg/kg;鸡蛋样品中5种磺胺类药物和甲氧苄啶在1.0～100.0μg/kg添加水平内的平均回收率在66.3%～97.5%之间,批内、批间相对标准偏差在1.4%～11.4%之间。该方法回收率满足残留检测要求,且方法的重现性良好,满足国内外兽药残留相关法规规定。     

QuEChERS-超高效液相色谱法-串联质谱法同时检测猪组织中赛庚啶及可乐定残留量

建立了Qu ECh ERS前处理结合超高效液相色谱-串联质谱同时检测猪组织中赛庚啶和可乐定残留量的方法。猪肉样品添加0.5 g C18粉,猪肝和猪肾样品添加3.0 g硫酸镁和2.0 g氯化钠,再分别加入10 m L 0.1%甲酸乙腈进行提取,提取液经浓缩后采用LC-MS/MS进行检测,内标法定量。该方法线性关系良好,猪肉、猪肝和猪肾中赛庚啶和可乐定在1~50μg/kg浓度范围内加标回收率分别为62%~112%和106%~121%,相对标准偏差均10%,方法检出限为0.5μg/kg。方法灵敏度高,选择性好,可作为猪组织中赛庚啶和可乐定残留量检测的确证方法。     

QuEChERS-超高效液相色谱串联质谱法同时测定鸡肉中7类42种兽药残留的研究

为了建立Qu ECh ERS结合超高效液相色谱-电喷雾电离串联质谱同时测定鸡肉中磺胺类、喹诺酮类、四环素类、酰胺醇类、大环内酯类、镇静剂类和金刚烷胺药物残留的分析方法,试验通过准确称取2 g均质样品,经Mcllvaine-Na_2EDTA缓冲溶液、[C4MIN]Cl溶液和甲酸乙腈溶液超声提取,氯化钠(Na Cl)盐析,无水硫酸镁(Mg SO4)、乙二胺-N-丙基硅烷化硅胶(PSA)和十八烷基硅烷键合硅胶(C18)净化后,超高效液相色谱-电喷雾电离串联质谱采用正、负电喷雾电离源,多反应监测(Multiple reaction monitoring,MRM)模式进行检测。结果显示:在最优试验条件下测得磺胺类、四环素类、氟喹诺酮类、酰胺醇类、大环内酯类、镇静剂类和金刚烷胺在1.0～100.0 ng/mL范围内线性良好,相关系数(R~2)均大于0.99;方法定量限为2.0～6.0μg/kg;在3个浓度添加水平下,平均回收率为72.5%～104%,RSD为2.37%～13.6%。研究结果表明试验建立的方法操作简单,具有很好的精密度与准确度,适合鸡肉中磺胺类、四环素类、氟喹诺酮类、酰胺醇类、大环内酯类、镇静剂类和金刚烷胺药物残留的同时检测。     

鸡蛋中多种磺胺类药物残留的检测方法研究

试验利用高效液相色谱法同时测定鸡蛋中9种磺胺类药物的残留。鸡蛋样品经60%乙醇水溶液(V/V)提取,提取液采用离心超滤装置净化,将离心超滤所得滤液进行HPLC分析。结果表明,用该方法测得磺胺类药物的最低检测限均为0.005μg/g,回收率均高于83.0%,能够满足鸡蛋中多种磺胺类药物残留检测的技术要求。     

高效液相色谱-串联质谱检测鸡蛋中5种新型喹喏酮类药物

采用超高效液相色谱串联质谱法建立鸡蛋中加雷沙星、曲伐沙星、莫西沙星、吉米沙星和加替沙星5种新型喹诺酮类药物残留的检测方法。样品经过2%甲酸乙腈提取、正己烷分步去脂,氮吹、Oasis HLB柱净化后,经Acquity UPLC BEH Shield RP18(100 mm×2.1 mm,1.7μm)分离,以甲醇和0.1%甲酸水溶液为流动相进行梯度洗脱,多反应监测扫描模式,5种新型喹诺酮类药物能在11 min内完好分离,方法的定量限均低于1.0μg/kg,在5.0~100.0μg/L浓度范围内,5种喹诺酮类药物线性良好,相关系数均在0.992以上;通过2、10、20μg/kg的加标回收试验表明,回收率为63.7%~88.3%,RSD%值为1.36%~11.5%。该方法能满足鸡蛋中新型喹诺酮类药物残留检测要求,对监控养殖过程非法添加隐患具有一定的参考价值。     

超高效液相色谱法测定鸡肉中氯羟吡啶和磺胺类药物残留的方法研究

为同时测定鸡肉中氯羟吡啶和9种磺胺类药物残留量,通过建立样品处理技术,优化目标化合物色谱条件,建立了一种超高效液相色谱(UPLC)法。样品用乙腈提取后,经RP18色谱柱分离,外标法定量,样品检测氯羟吡啶和9种磺胺类药物时间仅需3.9 min,在10~1 000 ng/m L浓度范围内呈良好线性关系,相关系数均大于0.999;在10、50、200μg/kg 3个添加水平回收率为69.0%~95.6%,相对标准偏差≤7.98%;检测限为3.0μg/kg,定量下限为10.0μg/kg。该方法简便、快速、灵敏度高,重现性好,可用于鸡肉组织中氯羟吡啶和9种磺胺类药物的快速定量检测。     

高效液相色谱法同时测定猪肌肉中氟喹诺酮类和磺胺类药物残留

为了建立同时检测猪肌肉组织中3种喹诺酮类药物(环丙沙星、单诺沙星、恩诺沙星)和3种磺胺类药物(磺胺二甲基嘧啶、磺胺间甲氧嘧啶、磺胺甲唑)的高效液相色谱(HPLC)检测方法,试验采用磷酸盐缓冲液(pH值为6)提取动物组织样品,混合型阳离子交换(MCX)固相萃取柱净化,无水乙醇平衡、洗涤,无水乙醇-氨水(95/5)洗脱,Symmetry C18色谱柱分离,紫外检测器串联荧光检测器同时测定。线性良好,相关系数(r2)大于0.998 7,平均回收率为70.6%~89.3%,相对标准偏差为2.5%~13.4%。喹诺酮类药物的检出限为0.04~0.20μg/kg,定量限为0.2~1.0μg/kg;磺胺类药物的检出限为4μg/kg,定量限为15μg/kg。结果表明:HPLC法具有快速、环保的特点,可以用于猪肌肉组织中氟喹诺酮类和磺胺类药物的常规残留检测。     

牛肉中磺胺类药物残留的检测分析

为建立用高效液相色谱法同时测定牛肉中6种磺胺类药物(磺胺二甲嘧啶、磺胺间甲氧嘧啶、磺胺甲噁唑、磺胺异噁唑、苯酰磺胺、磺胺二甲氧哒嗪)残留的方法。牛肉样品经均质匀浆、乙酸乙酯提取后,用MCX柱净化,洗脱液洗脱,6种磺胺类药物以0.1%甲酸-乙腈为流动相,在C18色谱柱上(100 mm×4.6 mm)分离。结果表明:6种磺胺药物浓度在0.01~5.00μg/m L范围内,其标准曲线的相关系数(R~2)在0.999 1~0.999 8范围内,加标回收率为67.6%~73.8%,相对标准偏差RSD为2.56%~7.12%(n=3),检出限为0.004~0.017μg/m L。所检测的样品中无磺胺类药残检出。     

超高效液色谱相法检测鸡蛋中氟喹诺酮类药物残留

超高效液相法检测鸡蛋中四种氟喹诺酮类药物残留,样品经1%甲酸乙腈提取后,荧光检测器检测分析。结果表明,四种氟喹诺酮类药物的峰面积与浓度呈现良好的线性关系,相关系数R20.9999。在环丙沙星、恩诺沙星、沙拉沙星添加浓度为10、100、200μg/kg和达氟沙星添加浓度为2、20、40μg/kg的情况下,四种氟喹诺酮类药物的回收率为73.4%~99.1%,各药物批内、批间相对标准偏差均小于10%,适用于鸡蛋中氟喹诺酮类药物残留的检测。     

商会自治的基石——商会自治规范研究

在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。     

癸氧喹酯干混悬剂含量测定的改进

采用高效液相色谱法测定癸氧喹酯干混悬剂的含量,在2-250μg/mL范围内,峰面积的常用对数与进样量浓度的常用对数呈良好的线性关系,R^2=1(n=5),平均回收率为99.24%~99.51%,RSD在0.05%~0.28%。此方法分析时间短,样品前处理简便、定量结果准确,重现性好,结果满意,为其质量控制提供了依据。     

猪毛色遗传的研究进展

本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。     

Comparison of 2 methods of centesis of the bursa of the biceps brachii tendon of horses

REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air.     

不同样本商品蜂蜜中硒含量的测定

用硝酸和高氯酸消化蜂蜜,使硒游离出来,在微酸性环境下,硒和2,3-二氨基萘(DAN)生成有较强荧光的物质,用环己烷萃取,在激发波长378nm,荧光波长518nm处测定其荧光强度。蜂蜜中硒含量范围:0.10～0.82μg/g。表明:蜂蜜应视为天然富硒营养品。     

乳酸杆菌益生作用机制的研究进展

乳酸杆菌作为益生菌广泛用于人和动物。本文综述了乳酸杆菌改善宿主健康的机制。乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道。文章重点讨论了乳酸杆菌表面成分（表面蛋白、脂磷壁酸和肽聚糖）与肠道受体（Ｃ型凝集素受体、Ｔｏｌｌ样受体和 Ｎｏｄ样受体）,阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制。     

Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF

Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo.     

Mechanism of Action of Probiotic Function of Lactobacilli

乳酸杆菌作为益生菌广泛用于人和动物.本文综述了乳酸杆菌改善宿主健康的机制.乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道.文章重点讨论了乳酸杆菌表面成分(表面蛋白、脂磷壁酸和肽聚糖)与肠道受体(C型凝集素受体、Toll样受体和Nod样受体),阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制.     

中华人民共和国农业部公告 第267号

为贯彻落实《兽药生产质量管理规范》(简称《兽药GMP》),进一步推动兽药GMP实施进程,我部制定了《兽药生产质量管理规范检查验收办法》,现予公告。本公告自2003年6月1日起施行。附件:兽药生产质量管理规范检查验收办法二○○三年四月十日第一章 总则 第一条 为推动《兽药生产质量管理规范》(以下简称兽药GMP)的实施,规范兽药GMP检查验收工作,制定本办法。 第二条 农业部负责全国兽药GMP管理和检查验收工作;负责制修订兽药GMP检查验收管理规定;负责兽药GMP检查员队伍建设和监督管理工作,负责国际兽药贸易中GMP互认工作。 …