Development of microformat imaging microplate and membrane immunoenzyme assays of the herbicide atrazine

Abstract

A microformat imaging technique in combination with registration of chemiluminescence by a charge-coupled device, CCD camera, were applied for the detection of the herbicide atrazine by two immunoenzyme assay formats – microplate and membrane assays. For the microplate (ELISA) case the detection limit was 95 pg mL⁻¹, giving a 9.5-fold enhancement in comparison with a traditional colorimetric assay. The membrane dot blot assay allowed detection of up to 40 pg mL⁻¹ of atrazine (4.5-fold enhancement). Due to the application of polyelectrolyte carriers for rapid reactants separation the membrane assay may be realized in 15 min. CCD-based registration of signals assures a high reproducibility of measurements; the variation coefficient is in the range 1–7%. The effectiveness of the assays developed for controlling triazine herbicides in mineral and tap water has been demonstrated.

Keywords:

• Enzyme immunoassay
• Atrazine
• Herbicides
• Chemiluminescence
• Charge-coupled device
• Microformat imaging

Acknowledgements

The investigations were supported by the Russian Foundation for Basic Research (project #03-04-48773), INTAS Research Project Grant #99-1461 and INTAS Young Fellowship #2002-371. The authors are thankful to Dr. E. V. Yazynina (Institute of Biochemistry, Moscow) for obtaining conjugates used in the membrane assays.