Analytical strategy based on the use of liquid chromatography and gas chromatography with triple-quadrupole and time-of-flight MS analyzers for investigating organic contaminants in wastewater

Open Access

Abstract

The presence of a wide variety of organic pollutants with different physico-chemical characteristics has been investigated in wastewater samples from a municipal solid waste treatment plant placed at Castellón, Spain. An advanced analytical strategy has been applied, consisting on the combined used of two powerful and complementary techniques, GC and LC, both hyphenated with tandem mass spectrometry with triple quadrupole analyzers. The GC-MS/MS method was based on sample extraction using C18 SPE cartridges and allowed the determination of around 60 compounds from different chemical families, such as PAHs, octyl/nonyl phenols, PCBs, organochlorine compounds, insecticides, herbicides and PBDEs. Most of compounds selected are included as priority contaminants in the European Union (EU) Water Directive. The UHPLC-MS/MS method, which provided high chromatographic resolution and sensitivity and short analysis time, used a sample extraction with OASIS HLB SPE cartridges and allowed the determination of 37 (more polar) pesticides. The methodology developed has been applied to the analysis of 41 water samples (20 non-treated, raw leachates, and 21 treated) collected between March 2007 and February 2009. Treated (reverse osmosis) water samples analyzed rarely exceeded 0.5 μg/L for the contaminants investigated. As expected, in non-treated leachates the number of detections and the concentration levels found were notably higher than in treated waters. The most commonly detected pollutants were herbicides (simazine, terbuthylazine, terbutryn, terbumeton, terbacil and diuron), together with fungicides (thiabendazole and carbendazim) and 4-t-octylphenol. In the light of data obtained, it has been proven that reverse osmosis process used for water treatment was efficient and notably reduced the levels of organic contaminants found in raw leachate samples. 2 In order to investigate the presence of other non-target contaminants, water samples were also analyzed by using GC-TOF MS and LC-QTOF MS. Several organic pollutants that ...