酶联免疫吸附（ELISA）法测定生猪尿液中的沙丁胺醇

将标准品、样品和和酶标记物一并加入到微孔板中孵育,样品中的游离沙丁胺醇与酶标记的沙丁胺醇竞争结合酶标板微孔中固定相化的沙丁胺醇特异性抗体,通过清洗步骤洗掉未结合的酶标记沙丁胺醇,再通过酶的专一性显色剂显色,微孔显蓝色,加入反应终止液使颜色由蓝色转为黄色。在450nm处测量吸光度（OD）值,并设置标准曲线,通过标准曲线测定样品中沙丁胺醇的含量,结果显示：OD值的大小与样品中沙丁胺醇的含量成反比。

Enzyme Linked Immunosorbent Assay for the Determination of Salbutamol in Pig Urine

Salbutamol standard,the sample solution and the enzyme-labelled salbutamol were added to the microwells.During the incubation,free and enzyme-labelled salbutamol competed for the antibody binding sites.Any unbound enzyme conjugate was then removed by washing.The bound enzyme activity was determined by adding a fixed amount of a chromogenic substrate.The enzyme converted the colorless chromogen into a blue product.The addition of the stop reagent lead to a color change from blue to yellow.The absorbance（OD） was measured by a microplate reader at 450 nm.A standard curve was drawn and the corresponding concentration of each sample from the standard curve was read.The result showed thet the color development was inversely proportional to the salbutamol concentration in the sample.