Pyridine compounds having a carboxyl side chain at the 2-position are attracting considerable attention for their ability. Chromium, manganese, iron, copper, zinc, and molybdenum are present as chelating agents in the human body. Picolinic acid acts as a chelating agent instead of these elements. In this study, the extraction of picolinic acid was studied using tridodecylamine (TDA) with respect to the functional groups of the diluents. All experiments reported on the extraction of picolinic acid by tridodecylamine (TDA) dissolved in different two different acetates (ethyl acetate and propyl acetate), two different alcohols (1-octanol and 1-decanol), and two different ketones (2-heptanone and 2-octanone), as well as single solvents. The experimental results of batch extraction experiments are reported as distribution coefficients, (K-D = C-PA/C-PA), loading factors, Z, and extraction efficiency, E. All measurements were carried out at 298.15 K. The highest distribution coefficient has been obtained by 1-octanol value of 4.121 and its extraction efficiency is 80%. Linear Solvation Energy Relationship (LSER) model has been applied to the experimental data with good regression coefficient, R-2:0.90. Model results are close to experimental results. (C) 2010 Elsevier B.V. All rights reserved.