Journal of Chromatography A, 873 (2000) 53–61 www.elsevier.com / locate / chroma Application of solid-phase microextraction–gas chromatography– mass spectrometry to characterize intermediates in a joint solar– microbial process for total mineralization of Aroclor 1254 * Chakib Rhofir, Jalal Hawari Biotechnology Research Institute, National Research Council Canada, 6100 Royalmount Avenue, Montreal ( PQ ), H4P 2R2 Canada Abstract A combined solid-phase microextraction–GC–MS analytical technique was used to monitor the formation of metabolites in the biodegradation of biphenyl, which were originally obtained from the solar photodechlorination of Aroclor 1254 by Pseudomonas pseudoalcaligenes KF707 and Burkholderia sp LB400. In both cases, the following metabolites were detected: 2-hydroxybiphenyl (2-OH-BP), 2,3-dihydroxybiphenyl (2,3-di-OH-BP), and benzoic acid, which was detected as its benzoate derivative 1-methylethylbenzoate. A time course study for the formation and disappearance of these metabolites was used to construct a degradation pathway, which in both cases, involved the formation of 2-OH-BP and 2,3-di-OH-BP. Crown copyright  2000 Published by Elsevier Science B.V. All rights reserved. Keywords: Mineralization; Aroclor 1254; Biphenyl; Hydroxybiphenyls; Benzoic acid 1. Introduction biotransformations in biological matrices [6]. Until recently, exhaustive sample preparation and sepa- Solid-phase microextraction (SPME) is a solvent- ration techniques (e.g. liquid–liquid extraction (LLE) less and rapid extraction technique that uses poly- followed by chromatographic clean-up procedures) mer-coated fibers for the extraction of organic com- were required to isolate and identify intermediates pounds from an aqueous or gaseous phase sample from biotransformation processes [5,7]. When such followed by thermal desorption in the injection port intermediates are formed in trace amounts, LLE may of a gas chromatograph for subsequent detection and not be as practical as SPME for the extraction of quantification. The technique is known for its speed such metabolites particularly from a fermentation 21 and sensitivity which enables detection in the mgl broth where emulsion formation, due to the presence range [1–5]. of surfactant-like products, constitutes an extraction Although SPME has been widely used for the and phase separation problem. Additionally, rela- trace analysis of organic compounds in several tively large volumes of organic solvents are needed aqueous based matrices, little is known on the during LLE. These problems added together may applicability of the technique for monitoring organic render LLE unsuitable for the detection of small quantities of (bio)degradation intermediates thus leading to the loss of valuable information on the *Corresponding author. Tel.: 11-514-496-6267; fax: 11-514-496- metabolic pathway. 6265. E-mail address: jalal.hawari@NRC.ca (J. Hawari) The main objective of this study was to apply 0021-9673 / 00 / $ – see front matter Crown copyright  2000 Published by Elsevier Science B.V. All rights reserved. PII: S0021-9673(99)00922-X