ANALYSIS OF POLYAROMATIC QUINONES IN A COMPLEX ENVIRONMENTAL MATRIX USING GAS-CHROMATOGRAPHY ION-TRAP TANDEM MASS-SPECTROMETRY

GC/MS and GC/MS/MS in a quadrupole ion trap were used to analyze for a nthraquinone, alkyl anthraquinones, benz[a]anthracene-7,12-dione and 9 -fluoranone in a sediment obtained from an aluminum smelter settling p ond contaminated with polycyclic aromatic hydrocarbons. By standard GC /MS analysis many of these target compounds were either undetectable o r their confirmation uncertain because of matrix interferences. Detect ion and identification were greatly improved by using GC/MS/MS. GC/MS/ MS analyses were performed by selecting the molecular ion (M) of a tar get compound and fragmenting it via collision induced dissociation (CI D) to yield product ions corresponding to loss of CO for unsubstituted compounds or CO plus CH3 for alkylated compounds. The CID conditions were optimized using anthraquinone and 2-methylanthraquinone standards by varying the CID excitation energy and RF storage levels to yield o ptimum amounts of fragment ions. CID experiments were performed using both resonant and non-resonant wave forms. Although both excitation te chniques gave comparable results for the removal of matrix interferenc es, non-resonant excitation provided more characteristic spectra for t he alkylated anthraquinones. Monitoring of secondary fragmentation pro ducts, such as M-2CO, provided greater discrimination from matrix inte rferences than the use of primary fragmentation products, such as M-CO . (C) 1997 Elsevier Science B.V.