| β-agonists, which is synthesized artificially by chemistry, is a kind of phenolethanolamine chemical substance possessing adrenergic function. The Ministry of Agriculture of the People’s Republic of China has restricted the use of β-agonists in animal breeding process, which was announced and documented according to article (No.176 and 1519). Therefore, it is necessary to develop a fast and easy-to-use method for detecting the β-agonists at low concentrations with satisfactory precision and accuracy for supervision and control. In this paper, microfluidic chip technology was first applied in determining β-agonists in swine hair. During the study, we suggested four different microfluidic analytical devices in which chemiluminescence method was performed in the determination of β-agonists in swine hair. The main results are as follows:Firstly, we found that β-agonists diminished the chemiluminescence generated by the reaction of luminol and KIO4 on the microfluidic paper-based analytical device (μPAD). On the basis of this phenomenon, a novel μPAD chemiluminescence sensor, which was designed as "96-well plate", was developed for the determination of total β-agonists in swine hair. About 48 samples could be detected on the same μPAD. The limit of detection of this method was recorded at 1.0×10-9mol/L. The degree of diminishment is proportional to the concentration of the P-agonists from 1.0×10-8 to 1.0×10-5mol/L.Two different reagents of chemiluminescence reaction could be added on the double-layer μPAD, so the double-layer μPAD is better. And on the μPAD, the stability of K3 [Fe (CN)6] was found better than that of KIO4. We also observed that the β-agonists diminished the chemiluminescence generated by the reaction of luminol and K3 [Fe (CN)6] on the μPAD, where the possible mechanism was studied. On the basis of this phenomenon, a novel double-layer μPAD chemiluminescence sensor was developed for the determination of total β-agonists in swine hair. The detection limit of this method was as low as 2.0×10-8mol/L. The degree of diminishment is proportional to the concentration of the β-agonists from 4.0×10-8 to 1.0×10-5mol/L.In addition to the methods on the μPAD, an analytical method was established on the glass chip in this paper. We observed that β-agonists with phenolic group have the ability to enhance the chemiluminescence generated by the reaction of luminol and K3[Fe (CN)6] in aqueous solution. On the basis of this phenomenon, a novel, sensitive, rapid, easy-to-use micro flow injection chemiluminescence analysis system on a microfluidic glass chip was established in the determination of ractopamine, salbutamol and terbutaline in swine hair. The limits of detection according to the method used are as follows:2.0×10-8mol/L of ractopamine,1.0×10-8mol/L of terbutaline and 5.0×10-7 mol/L of salbutamol. When compared with the methods used on the μPAD, the repeatability of the method used on the glass chip was better. And the glass chip can be reused.At last, a post-chemiluminescence phenomenon was observed when β-agonists were added to a mixture of luminol and KIO4 after the chemiluminescence reaction between luminol and KIO4 had finished. On the basis of this phenomenon, we presented a micro flow injection post-chemiluminescence analysis system on the glass chip for the determination of β-agonists in swine hair. The detection limit recorded was at 1.0×10-9mol/L. The intensity of chemiluminescence is proportional to the concentration of the β-agonists from 5.0×l0"9 to 1.0×10-7mol/L. When compared with the traditional chemiluminescence method, the sensitivity of this method was found to be 5 times higher.In summary, microfluidic analytical devices in which chemiluminescence method was performed in determining β-agonists in swine hair was observed to be highly sensitivity, easy to use, fast, reducing the reagents consumption, simple instrument and low cost. The merits of the proposed system make it attractive for developing miniaturization instrument for on-site analysis. |
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