Concentration dependent red shift: qualitative and quantitative investigation of motor oils by synchronous fluorescence scan

Synchronous fluorescence scan (SFS) has been described as a successful tech nique to characterize Motor oils like diesel, petrol, kerosene, 2T oil and Mobil. The concentration dependent investigation of Motor oils shows a red shift in lambda (max)(SFS). Using red shift of lambda (max)(SMS), a method has been developed to quantify Motor oil in the concentration range 5-100% v/v. The concentration dependent overall rate of energy transfer of Motor o il gives a unique behavioral change according to the oil type and SFS is a simpler spectroscopic method to qualitatively differentiate between heavy a nd light oil. The molecular interaction of polycyclic aromatic compounds (P ACs) in fluorophoric mixtures like resonance energy transfer and self-quenc hing via solvent collision has been clearly explained by SFS method. Effect of solvent and external quencher molecule on Motor oils has also been stud ied. Nitrobenzene is found to be a selective quencher for PACs of Motor oil s. (C) 2001 Elsevier Science B.V. All rights reserved.