title: Trace determination of beta-lactam antibiotics in surface water and urban wastewater using liquid chromatography combined with electrospray tandem mass spectrometry.
abstract: A sensitive and reliable method using liquid chromatography-electrospray tandem mass spectrometry has been developed and validated for the trace determination of beta-lactam antibiotics in natural and wastewater matrices. Water samples were enriched by solid-phase extraction. The analytes included amoxicillin (AMOX), ampicillin (AMP), oxacillin (OXA), cloxacillin (CLOX) and cephapirin (CEP). Average recoveries of beta-lactams (BLs) in fortified samples were generally above 75% (except amoxicillin) with the standard deviations lower than 10% in water matrices. Amoxicillin was not quantified due to poor recovery (less than 40%) in the investigated water matrices. Matrix effects were found to be minimal when measuring these compounds in water matrices. The accuracy, within- and between-run precision of the assay fell within acceptable ranges of 15% absolute. The method detection limit (MDL) was estimated to range between 8 and 10 ng/L in surface water, 13 and 18 ng/L in the influent and 8 and 15 ng/L in the effluent from a wastewater treatment plant. A large number of actual water samples were analyzed using this method in order to evaluate the occurrence of the beta-lactams in a river and a wastewater treatment plant in northern Colorado. Most of the samples were negative for all analytes. These compounds were found at 15-17 ng/L in the three influent samples and at 9-11 ng/L in three surface water samples out of a total of 200 samples. This indicates that contamination by beta-lactam antibiotics is of minor importance to the small mixed-watershed.
authors.affiliation: Department of Civil and Environmental Engineering, Colorado State University, Fort Collins, CO 80523-1372, USA.
authors.forename: J M
authors.initials: JM
authors.lastname: Cha
authors.forename: S
authors.initials: S
authors.lastname: Yang
authors.forename: K H
authors.initials: KH
authors.lastname: Carlson
mesh_terms: D000900:Anti-Bacterial Agents / Q000032:analysis*; D002853:Chromatography, Liquid / Q000379:methods*; D005618:Fresh Water / Q000737:chemistry; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012722:Sewage / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis*; D047090:beta-Lactams / Q000032:analysis*
chemical_list: D000900:Anti-Bacterial Agents; D012722:Sewage; D014874:Water Pollutants, Chemical; D047090:beta-Lactams