[Application of fluorescence microscopic imaging technique with self-ordered ring to residues detection of...

Fluorescence microscopic self-ordered ring (SOR) technique with microwave heating is proposed for minocycline based on the capillary flow of solvent on the surface of hydrophobic glass slide and applied to residues detection of the antibiotics in milks of Inner Mongolia. In the reaction medium of hexahydropyridine containing polyvinyl alcohol-124 (PVA-124), a SOR of minocycline with the outer diameter of 1.54 mm and the ring belt width of 22.6 microm can be formed. When a 0.30 microL droplet of minocycline mixture was spotted on the solid surface, minocycline in the range of 4.2 x 10(-2)-1.8 x 10(-11) mol x ring(-1) (1.4 x 10(-6)-0.60 x 10(-5) mol x L(-1)) can be detected, the maximum fluorescence intensity was found to be proportional to the minocycline concentration, and the limit of detection can reach 4.2 x 10(-13) mol x ring(-1) (1.4 x 10(-7) mol x L(-1)) with three times of signal to noise ratio. With the present method, the contents of minocycline in milk samples of Inner Mongolia and minocycline hydrochloride capsule sample were satisfactorily determined with recoveries of 97.2%-103% and 99.4%-102%, respectively, and RSD lower than 1.2%, correspondingly. Therefore, a highly sensitive and selective analysis method for detecting content of trace drug contaminations was established. The method provided theory basis to quantificational analysis of the residues of the antibiotics in milks which was Inner Mongolia' preponderant resource products. It has important realistic meaning and broad application prospect.