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Abstract

A new method for analysis of polar terpene oxidation products in secondary aerosols is described. It is based on collection of particles on Teflon filters and extraction with dichloromethane followed by analysis with liquid chromatography (LC) ion-trap mass spectrometry (MS[n]) using pneumatically assisted electrospray ionistion (ESI) and atmospheric pressure chemical ionistion (AOCI) with the ion-trap operated in the product scan mode. Sparations are achieved on a C[18] reversed phase column with methanol/water (0.1 % acetic acid) as eluent. The method has a high sensitivity (Instrument Detection Limit 0.7-7 pg/uL at S/N=3) and precizion (5-10%) and a good linearity.
Acidic oxidation products produce strong signals with ESI. They appear as negative quasi-molecular ions [M-H] acetate adducts [M+CH (3)COO] and molecular clusters[2M-H]. In the MS(2) mode these acids show strong signals from neutral loss of CO(2)[M-H-CO(2)] and/or weaker signals from loss of H(2)O:[M-H-H(2)O],[M-H-h(2)O-CO(2)].Mass spectra were recorded by APCI for a number of oxygenated terponoid standards containing keto-groups, hydroxy-groups, aldegyde groups, or epoxy-groups. Thes compounds give intense signals as their positive quasi-molecular ions [M+H](+), methanol aducts [M+H+CH(3)OH-H(2)O](+) and [M+H-2H(2)O](+).By MS(2) and MS(3) neutral loss of H(2)O and H(2)O is observed.
The method has been tested in analysis of aerosol from O(3)/a-pinene and O(3)/myrtenol and proved to compare well with classical methods based on derivatization and gas chromatography mass spectrometry (GC-MS). Three new compounds, tentatively identified in aerosol are reported here for the first time: 10-hydroxy-pinonic acid, 9-hydroxy-norpinonic acid and pinalic 4 -acid. .

Additional information

Authors: GLASIUS M, Environment Institute, JRC Ispra (IT);DUANE M, Environment Institute, JRC Ispra (IT);LARSEN B R, Environment Institute, JRC Ispra (IT)
Bibliographic Reference: Article: Journal of Chromatography, 1998
Record Number: 199910278 / Last updated on: 1999-03-12
Category: PUBLICATION
Original language: en
Available languages: en
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