The power of pentafluorobenzyl alcohol chemical ionization/ion trap mass spectrometry to identify pentafluorobenzyl derivatives of oxygenated polar organics

Chamber studies establish that oxygenated and polar organics such as carbon yls, dicarbonyls, hydroxy carbonyls, epoxy carbonyls, oxo acids, and hydrox y carboxylic acids are photooxidation products of biogenic and anthropogeni c hydrocarbons. To date, with the exception of carbonyls and carboxylic aci ds, few studies report ambient measurements of oxygenated and polar organic s because of a lack of suitable methodologies. Such measurements are critic al to establish the accuracy of photochemical models that incorporate chamb er data, and are formulated to devise strategies to improve air quality. He re, we demonstrate the power and utility of pentafluorobenzyl alcohol (PFBO H) to identify pentafluorobenzyl derivatives of oxygenated and polar organi cs. The PFBOH chemical ionization (CI) mass spectrum comprises three primar y ions at m/z 181 (C6F5CH2)(+), 197 (C6F5CH2O)(+), and 198 (C6F5CH2OH)(+.). We report the presence of (M - H)(+), (M)(+.), (M + H)(+), and (M + 181)() ions in the PFBOH mass spectra that create a unique pattern which facilit ates molecular weight determinations. By conducting experiments in which th e reagent ions were selected prior to reaction with the derivative molecule s, we established that the m/z 181 reagent ion effects the formation of an (M + 181)(+) adduct ion. The data also suggest that the m/z 197 ion primari ly affects proton addition reactions, and that the m/z 198 ion promotes cha rge exchange and hydride abstraction reactions. We establish the practicali ty and power of PFBOH to identify pentafluorobenzyl derivatives in this and previous work. The knowledge gained regarding ion/molecule reactions of PF BOH chemical ionization (CI) was utilized to identify a pentafluorobenzyl d erivative in an extract of fine particulate matter of diesel motor vehicle exhaust in a traffic tunnel. The combination of pentafluorobenzyl derivatiz ation, PFBOH, and ion trap mass spectrometry assisted the identification of 4-hydroxybenzoic acid as a component of the particulate organic matter. (I nt J Mass Spectrom 190/191 (1999) 343-357) (C) 1999 Elsevier Science B.V.