Development of a competitive indirect ELISA for the determination of lincomycin in milk, eggs, and honey.
Polyclonal antibodies to lincomycin (LIN) were developed in rabbit as a result of immunization with BSA-LIN conjugate. Periodate oxidizing of hapten was the common step of both immunogen synthesis and preparation of conjugated antigens for coating plates (homologous and heterologous). Several ELISA variants on a base of the different antigens immobilized on polystyrene were compared. Heterology of solid-phase antigens was provided with relative hapten clindamycin (CLIN) and ethylene- or hexanediamine as spacer arm between hapten and carrier. The spacer insertion yielded no desirable effect, whereas gelatin-CLIN assay variant showed better test characteristics in comparison with the homologous one, although insignificant (IC(50) was 9.15 vs 18.3 ng mL(-1)). The detection limits of the developed test, being estimated as 0.43 ng mL(-1) (milk) and 0.65 ng mL(-1) (eggs), were sufficient to measure maximum residue levels for LIN in examined matrices. This value for honey was 1.9 ng mL(-1) (1.3 μg kg(-1)). The assay sensitivity was enough to dilute milk, egg, and honey samples by 10-100 times to minimize matrix effect. The examination of matrix effect and simple ways of its overcoming are detailed in the paper. The developed assay showed 111% cross-reactivity with CLIN; therefore, it is suitable for the determination of both lincosamides.
Burkin
Maksim A
MA
Department of Hybridomas, Mechnikov Research Institute for Vaccine and Sera, Russian Academy of Medical Sciences, Maliy Kazionniy per. 5a, Moscow, 105064 Russia. burma68@yandex.ru
Galvidis
Inna A
IA
D000818:Animals; D000900:Anti-Bacterial Agents / Q000032:analysis* / Q000276:immunology; D002645:Chickens; D004350:Drug Residues / Q000032:analysis*; D004531:Eggs / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay; D005513:Food Inspection / Q000379:methods*; D006722:Honey / Q000032:analysis*; D008034:Lincomycin / Q000032:analysis* / Q000276:immunology; D008892:Milk / Q000737:chemistry*
D000900:Anti-Bacterial Agents; D008034:Lincomycin