基于免疫胶体金试纸条检测盐酸克伦特罗的便携式光电型传感器

利用免疫竞争抗制原理制备检测盐酸克伦特罗的免疫纳米金试纸条,盐酸克伦特罗与CLB-BSA复合物竞争性结合胶体金上抗体的有限位点,从而使试纸条上的检测带显色减弱或消失.将显色后的试纸条插入自行研制的光电型传感器的测试孔内,根据反射光的强弱计算出克伦特罗的浓度.结果表明:用光电传感方法检测盐酸克伦特罗的线性范围为1～10 μg/L,检出限为0.05 μg/L,回收率为85.5％～96.0％.此光电型传感器检测克伦特罗具有简便、快速、灵敏、特异性强的优点.     

基于纳米金固定半抗原的电化学免疫传感器灵敏检测克伦特罗

研制了一种基于纳米金固定半抗原的间接竞争电化学免疫传感器,可灵敏检测克伦特罗.在金电极表面组装1,6-己二硫醇单分子膜,通过Au-S共价作用连接纳米金颗粒,通过吸附作用固定克伦特罗牛血清白蛋白偶联物.样品中的待测组分与固定化的克伦特罗偶联物竞争结合单克隆抗体,碱性磷酸酯酶标记的二抗选择性地与电极表面捕获的一抗反应,进而催化底物1-萘酚磷酸酯水解生成1-萘酚,在电极表面氧化产生电信号.在优化的实验条件下,克伦特罗浓度在0.1～1000 μg/L范围内与电流强度线性相关,线性方程为I(A)-8.79× 10-7-2.66× 10-7logC (μg/L),相关系数0.9960,检出限达20 ng/L.同时测定了猪肉及猪肝样品中克伦特罗含量,相对标准偏差平均值为7.0％,加标回收率在89.1％～105.6％之间,与传统的间接竞争酶联免疫吸附法对照,结果无显著性差异.     

Trace determination of clenbuterol with an MWCNT-Nafion nanocomposite modified electrode

A method for the determination of trace clenbuterol is described. Multi-walled carbon nanotubes (MWCNTs)-Nafion composite was used to modify the glassy carbon electrode (GCE). The modified electrode showed high sensitivity and good selectivity for clenbuterol detection. It offered a linear range of 1.0 × 10⁻⁹–1.0 × 10⁻⁶ mol · L⁻¹ with a detection limit of 5.0 × 10⁻¹⁰ mol · L⁻¹ in pH = 1.2 solution. The oxidation mechanism of clenbuterol on the electrode was also investigated. Correspondence: Xiao-Ya Hu, Department of Chemistry, Yang Zhou University, Yang Zhou, Jiang Su, P.R. China     

1 H NMR Spectral Simplification with Achiral and Chiral Lanthanide Shift Reagents. Clenbuterol. Method for Direct Optical Purity Determination

The 60 MHz ¹H NMR spectra of clenbuterol, 1, have been studied in CDCl₃ solution with the achiral shift reagent, tris (6,6,7,7,8,8,8-hepta-fluoro-2,2-dimethyl-3,5-octanedionato)europium (III), 2, and the chiral reagent tris[3-(heptafluoropropylhydroxyn1ethyl-ene)-(+)-canphorato]europiunr(III), 3. Use of 3 resulted in observable enantiomeric shift differences, ΔΔσ, for the t-butyl, NH₂ benzylic CH and the aryl proton signals. Values of ΔΔσ as high as 135.1 Hz (2.25 ppm) and 86.5 Hz (1.44 ppn) were seen for the methine and aryl protons, respectively, with a solution 0.1035 molal in 1 and a 1:3 molar ratio of 0.551. The aryl resonance is especially well suited for direct optical purity determinations of 1.     

固相萃取-高效液相色谱法同时测定克伦特罗和沙丁胺醇

提出用固相萃取 -高效液相色谱法同时测定饲料中微量克伦特罗和沙丁胺醇的新方法。选用 Dikma Diamonsil C18-ODS分析柱 (2 0 0× 4.6mm,5μm) ,乙腈 -0 .0 1mol/ L KH2 PO4 (p H 3 .0 )作流动相 ,应用波长编程进行检测。克伦特罗和沙丁胺醇的线性范围为 0 .1～ 1 0 0μg/ m L,相关系数分别为 0 .99999和 0 .99977,检出限分别为0 .3 1 ng/ m L和 0 .2 4ng/ m L ,回收率分别为 91 .2 %～ 92 .0 %和 91 .9%～ 93 .0 % ,相对标准偏差分别是 1 .2 0 %～ 2 .0 5%和 1 .2 9%～ 2 .51 %。     

电子束辐照下克伦特罗的降解研究

克伦特罗(clenbuterol)属于儿茶酚胺衍生合成的一类化合物,化学名称为4-胺基-α-(叔丁胺甲基)-3,5-二氯苯甲醇。克伦特罗为β2受体兴奋剂,能较强地影响体内物质代谢,促进动物肌肉蛋白质的合成,抑制脂肪的合成和积累,从而改变胴体的品质,使生长速度加快,胴体瘦肉率提高10％以上,所以有人干脆将其称为"瘦肉精"。克伦特罗作为饲料添加剂,其使用剂量较高,且使用时间较长(3周以上),并且由于具有极强的热稳定性和生化稳定性,动物食用后,在内脏和组织中形成严重的蓄积性残留,人食用了含有这些药残的动物组织后,会产生严重的毒副作用,故欧美及我国农业部严禁使用克伦特罗做为动物生长促进剂、饲料添加剂。但资料显示,1999年农业部组织的猪配合饲料和饮用水中盐酸克伦特罗抽查检出率为19.8％,2000年抽查检出率为7.6％。为保障消费者的食用安全和各国贸易的正常往来,本文探索了一种使克伦特罗降解的方法--电子束辐照法。     

Liquid chromatographic analysis of clenbuterol residues in food products of animal origin (cow liver) using diphasic dialysis extraction

Summary This paper reports a method employing diphasic dialysis extraction for the rapid confirmation of clenbuterol in cow liver by RPHPLC with diode-array detection. The most suitable means of homogenizing the liver is in barium hydroxide-barium chloride buffer; the optimum extraction solvent istert-butyl methyl ether at an extraction temperature of 37°C; stirring should be applied at 150 r.p.m. for 4h. This extraction method improves clenbuterol recovery values to 98.9%.     

Influence of the storage conditions on the concentration of clenbuterol in cattle urine samples

A study of the stability of clenbuterol in cattle urine samples under different time and temperature storing conditions is reported. At the farm, urine samples were spiked with several amounts of this compound. Then, they were immediately transported to the laboratory and stored at room temperature, between 4 and 8 °C and frozen. Clenbuterol was quantified by using high performance liquid chromatography with diode-array detection (HPLC-PDA) on days 1, 7 and 42 after sample collection. The drug concentration in frozen urine samples was apparently stable during the whole studied period. However, there was a notable decrease in the concentration of this analyte when samples were stored at room temperature and between 4 and 8 °C, specially during the first week. A complementary study showed that the decrease in clenbuterol concentration was particularly significant from 1st to 4th day after sample collection and when urine specimens were kept at room temperature. Based on the results of this study, it was concluded that sample freezing as soon as possible after collection is the most adequate way to guarantee that the reliable concentration of clenbuterol in urine specimens remains unchanging until sample analysis.     

Three-phase solvent bar microextraction and determination of trace amounts of clenbuterol in human urine by liquid chromatography and electrospray tandem mass spectrometry

Three-phase solvent bar microextraction (TPSBME) technique is described for the quantitative determination of trace amounts of clenbuterol (CB) in urine samples using liquid chromatography (LC) and electrospray tandem mass spectrometry (ES-TMS). CB was extracted from a basified urine sample (donor phase) into the organic solvent residing in the pores of a freely moving hollow fiber and then back extracted into an acidic solution (acceptor phase) inside the lumen of the hollow fiber. The ends of the fiber were pressure-sealed. Here, forward and back extraction took place spontaneously. We studied various parameters affecting the extraction efficiency viz. type of organic solvent (octanol, nonanol and dihexyl ether) used for immobilization in the pores of the hollow fiber, i.e. extraction time (10-40 min), stirring speed (0-1000 rpm), effect of sodium chloride (0-25%, w/v) and concentration of the donor (0.25-3 M NaOH) and the acceptor (0.5-5 M formic acid) phases. After extraction, CB was analyzed by injecting the analyte enriched acceptor phase into LC combined with ES-TMS. Enrichment factor (79), repeatability (R.S.D. = 5.1%), correlation coefficient (0.9972, for the range of 0.1-4 ng mL⁻¹), detection limit (7 pg mL⁻¹) were also investigated. The present technique is compared with the reported solid phase microextraction techniques in terms of selectivity, analysis time per extraction, cost of analysis per extraction, and precision. Among all microextraction techniques reported, this technique is the most economical sample preparation/preconcentration technique to our knowledge. The method was applied for the analysis of CB in human urine.     

Gas chromatographic-tandem mass spectrometric analysis of clenbuterol residues in faeces

In all EU member states, the use in livestock farming of certain substances having a hormonal action is prohibited. Clenbuterol, the β-adrenergic agonist, has some growth promoting characteristics. Screening for clenbuterol can be carried out by an immunoassay. Gas chromatography-mass spectrometry (GC-MS) is very valuable for confirmatory purposes. In full scan MS it is impossible to fulfil the EU criteria of four diagnostic ions with one single ionisation mode. Some alternative possibilities are: (1) the use of two different ionisation modes, (2) the use of different derivatization methods or (3) the use of tandem MS. Each derivatisation or ionisation mode on its own did not give a sufficient number of ions. By combining these different possibilities we were able to obtain four ions, fulfilling the EU criteria.