Figure 2: The coincidence spectra of the derivative of the ratio spectra of (a) 10 µgml-1 MEH (____) and ternary mixture (-----) (10 µgml-1 MEH, 15 µgml-1 DF and 20 µgml-1 MET). (b) 10 µgml-1 DF (------) and ternary mixture (-----) (2 µgml-1 MEH, 10 µgml-1 DF and 15 µgml-1 MET). (c) 20 µgml-1 MET (____) and ternary mixture (-----) (10 µgml-1 MEH, 15 µgml-1 DF and 20 µgml-1 MET).