New immunosensors for 2,4-D and 2,4,5-T pesticides determination

Abstract

New immunosensors for 2-(2, 4-dichlorophenoxy) acetic acid (i.e. 2,4-D) and (2, 4, 5-trichlorophenoxy) acetic acid (i.e. 2,4,5-T) pesticide determination were developed using a non commercial antibody, hydrogen peroxide transducer and horseradish peroxidase as enzyme marker. The results show the full validity of these immunosensor devices, which were optimized using a ‘competition’ separation procedure. These immunosensors were also used to test pesticide recovery in common real matrices such as field grass, maize and wheat samples, for which good results were obtained. The immunosensors developed demonstrated a good selectivity versus different kinds of pesticides and may thus be considered as suitable devices for application to real matrices (LOD = 8.0 × 10⁻¹¹mol L⁻¹; RSD% = 5.2 for 2,4-D and LOD = 2.8 × 10⁻⁹mol L⁻¹; RSD% = 6.1 for 2,4,5-T).

Keywords:

• immunosensor
• competition procedure
• chlorinated herbicides
• vegetal matrices

Acknowledgements

We are indebted to Professor Sergei Eremin (Department of Chemical Enzymology, M. V. Lomonosov Moscow State University, Russia) for providing the antibodies used in this work.

This work was funded by ‘La Sapienza’ University of Rome, Ateneo Project’.