title: Analysis of benzylsuccinates in groundwater by liquid chromatography/tandem mass spectrometry and its use for monitoring in situ BTEX biodegradaton.
abstract: Benzylsuccinic acid (BS) and methylbenzylsuccinic acid (MeBS) isomers have been proposed as distinctive indicators of anaerobic toluene and xylene metabolism in fuel-contaminated aquifers; however, labor-intensive analytical procedures have limited their analysis at field sites. In this article, a rapid electrospray LC/MS/MS (liquid chromatography/mass spectrometry/mass spectrometry) method for benzylsuccinates is described that involves selected reaction monitoring, internal standard quantification with [ring-2H5]BS, small sample size (<1 mL), and no extraction/concentration steps. The highly selective LC/MS/ MS method was shown to be sensitive (detection limits ca. 0.3 microg/L), accurate, and precise. The method was used to characterize geographic and temporal distributions of BS and MeBS isomers in an anaerobic, hydrocarbon-contaminated aquifer. BS was never detected, and MeBS isomers were detected in the three wells with the highest concentrations of BTEX (benzene, toluene, ethylbenzene, and xylenes); MeBS concentrations ranged from <0.3 to 205 microg/L. A strong linear correlation (r2 = 0.94; n = 12) was found between concentrations of total MeBS isomers and their parent compounds, xylenes, which suggests that anaerobic xylene metabolism at this site was probably first-order rather than zero-order. The novel LC/MS/MS method for BS and MeBS isomers is a promising technique for rapid and reliable monitoring of in situ bioremediation of gasoline-contaminated groundwater.
authors.affiliation: Lawrence Livermore National Laboratory, California 94551, USA. beller2@llnl.gov
authors.forename: Harry R
authors.initials: HR
authors.lastname: Beller
mesh_terms: D001673:Biodegradation, Environmental; D002274:Carcinogens, Environmental / Q000378:metabolism; D002853:Chromatography, Liquid; D004784:Environmental Monitoring; D005742:Gasoline; D013058:Mass Spectrometry; D012680:Sensitivity and Specificity; D012989:Soil Pollutants / Q000032:analysis* / Q000378:metabolism; D013386:Succinates / Q000032:analysis*; D014050:Toluene / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000378:metabolism; D014881:Water Supply; D014992:Xylenes / Q000378:metabolism*
chemical_list: D002274:Carcinogens, Environmental; D005742:Gasoline; D012989:Soil Pollutants; D013386:Succinates; D014874:Water Pollutants, Chemical; D014992:Xylenes; C030196:benzylsuccinate; D014050:Toluene