Determination Of Beta-agonists Using Microfluidic Chip Coupled With Surface-Enhanced Raman Spectroscopy (SERS)

Beta-agonists are often used as feed additive in the livestock industry because they are able to improve the carcass composition by reducing the fat deposition and increasing the muscle mass, however, they are prohibited for use as a growth promoting agents because side effects may carry over to people. We can determine whether farmers illegally use beta-agonists by measuring beta-agonists in swine hair. Conventional liquid chromatography and mass spectroscopy (LC-MS) analytical technique is time-consuming and tedious, furthermore, cumbersome equipment makes analysis only possible at the central lab. Herein, it is possible for combining Surface-enhanced Raman Spectroscopy (SERS) with microfluidic chip to develop simple, fast, point of care testing methods for measurement of beta-agonists in swine hair. Specifically achieved:(1) Determination of beta-agonists by paper microfluidics coupled with SERSThe3D paper microfluidic used in this study was fabricated by wax printing. It can filtrate the swine particle and enrich beta-agonists in swine hair extract by folding the microfluidic paper. Synthesis and characterization of different kinds of nanoparticles as Au, Ag, and Au@SiO2and screening their SERS enhancement effect. Finally, we choose55nm Au nanoparticle as SERS substrate. We adjust pH conditions on paper chip, aim at finding the suitable pH for different beta-agonists. In acidic condition, characteristic band of clenbuterol, ractopamine and terbutaline did not overlap and were simultaneously identified with a detection limit around ng/mL. In alkaline condition, characteristic band of salbutamol, clencyclohexerol and ritodrine can be resolved separately and determined simultaneously with a detection limit around ng/mL.(2)The SERS detection based on glass chipConstructing glass chip used for beta-agonists detection. The system includes extraction module, separation and enrichment module, and the detection module. Extraction of clenbuterol in swine hair was achieved by micro heater and circulation system in extraction module on chip; clenbuterol can be purified by C18and MIP solid phase extration column in separation and enrichment module; By Fe3O4@Au magnetic nanoparticles and applied magnetic field, online and dynamic SERS detection of clenbuterol was achived in detection module.