Detection of pesticide model compounds in ethanolic and aqueous microdroplets by nonlinear Raman spectroscopy

Anal Chem. 2001 Jul 1;73(13):3146-52. doi: 10.1021/ac010169a.

Abstract

Pesticide model compounds are detected in microdroplets by means of in situ nonlinear Raman spectroscopy. The chloro- and nitro-substituted aromatics are dissolved in ethanol as well as in water. Their vibrational spectroscopic fingerprint, that is, Raman bands characteristic of the functional groups attached to the aromatic system, is determined in bulk medium by linear Raman spectroscopy. As a result of the concept of group vibrations, the chosen compounds can be regarded as representatives for a whole class of pesticides containing these residues. External seeding of stimulated Raman scattering (SRS) is applied for the detection of these group vibrations of the pesticide model compounds. This technique can be utilized for in situ diagnostics and a noninvasive vibrational spectroscopic analysis of the chemical composition of microdroplets with natural or anthropogenic origin.