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International Journal of Analytical Chemistry
Volume 2015, Article ID 347621, 10 pages
http://dx.doi.org/10.1155/2015/347621
Research Article

Highly Sensitive Immunochromatographic Identification of Tetracycline Antibiotics in Milk

1A.N. Bach Institute of Biochemistry, Research Centre of Biotechnology of the Russian Academy of Sciences, Leninsky Prospect 33, Moscow 119071, Russia
2Institute of Physical Organic Chemistry, Surganov Street 13, 220072 Minsk, Belarus
3Institute of Bioorganic Chemistry, Acad. Kuprevich Street 5/2, 220141 Minsk, Belarus
4Chemical Department, M.V. Lomonosov Moscow State University, Leninskie Gory, Moscow 119991, Russia

Received 17 September 2015; Accepted 4 November 2015

Academic Editor: Josep Esteve-Romero

Copyright © 2015 N. A. Taranova et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A rapid immunochromatographic assay was developed for the control of tetracycline (TC). The assay is based on the competition between immobilized TC-protein conjugate and TC in a tested sample for binding with polyclonal anti-TC antibodies conjugated to colloidal gold during the flow of the sample along a membrane strip with immobilized reactants. Conjugation of colloidal gold and the total immunoglobulin (IgG) fraction of polyclonal antibodies was used to increase the assay sensitivity to ensure low content of specific antibodies in the conjugate. This allowed effective inhibition of free TC and conjugate binding in the strip test zone. Photometric marker registration allows control of the reduction of binding, thereby enhancing detection sensitivity. The proposed assay allows TC to be detected at concentrations up to 20 ng/mL, exceeding the limit of detection of the known analogues, in a wide working range (more than two orders) of 60 pg/mL to 10 ng/mL, ensured through the use of polyclonal antibodies. The assay time is 10 min. The efficiency of the designed assay is shown to identify TC in milk; the degree of recovery of TC ranges from 90 to 112%. The precision of the concentrations measurements was no more than 10%.