Determination of Tetracycline Residue in Food by a Simple Resonance Rayleigh Scattering Method

A novel method for the determination of TC using resonance rayleigh scattering (RRS) technique was established. The resonance rayleigh scattering (RRS) spectra of 3-(4´-nitrophenyl)-5-(2´-sulfonicphenylazo) rhodanine (4NRASP) with tetracycline (TC) was studied. Experimental result showed that when lambda_ex = lambda_em = 394 nm, the RRS peak of 4NRASP was greatly enhanced with the increase of TC concentration at a pH of 5.5 Britton-Robinson(B-R) buffer solution and the medium of SDS micro-emulsion. The linear range of the calibration curve for TC was 0.05~3.30 mug-mL^-1. The detection limit was 2.95 times 10^-10 g-mL^-1. The method has been applied to the determination of the trace amount of TC in food samples with satisfactory results. The reaction mechanism was discussed in this work.