title: Pressurised hot water extraction followed by headspace solid-phase microextraction and gas chromatography-tandem mass spectrometry for the determination of N-nitrosamines in sewage sludge.
abstract: A method for the quantitative determination of the nine EPA N-nitrosamines in sewage sludge was developed by using pressurised hot water extraction (PHWE) followed by headspace solid-phase microextraction (HS-SPME) and gas chromatography coupled to chemical ionization ion trap tandem mass spectrometry (GC-CI-MS-MS). The pressurised hot water extraction was optimized using a central composite design with regard to operational parameters such as temperature, extraction time and pH of water as extracting solvent. The optimum conditions were: water at pH 7.5 as extracting solvent, temperature of 125°C and extraction time of 5 min. The sewage sludge extract was automatically analyzed by HS-SPME using a divinylbenzene/carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber and GC-CI-MS-MS. The limits of detection of all compounds were lower than 0.15 μg/kg of dry weight (d.w.) of sewage sludge. The repeatability and reproducibility between days (10μg/kg d.w.) expressed as relative standard deviation were lower than 16 and 19%, respectively. The method was applied to determine the N-nitrosamines in sewage sludge from urban and industrial sewage treatment plants (STPs) and from a potable water treatment plant. Some N-nitrosamines were determined in the samples and N-nitrosodiethylamine (NDEA) and N-nitrosodi-n-butylamine (NDBA) showed the highest values (371 and 305 μg/kg (d.w.), respectively) in sewage from industrial STPs.
authors.affiliation: Department of Analytical Chemistry and Organic Chemistry, Rovira i Virgili University, Sescelades Campus, Marcel lí Domingo s/n, Tarragona 43007, Spain.
authors.forename: Anna
authors.initials: A
authors.lastname: Llop
authors.forename: Francesc
authors.initials: F
authors.lastname: Borrull
authors.forename: Eva
authors.initials: E
authors.lastname: Pocurull
mesh_terms: D004129:Dimethylpolysiloxanes / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D059627:Liquid Phase Microextraction / Q000379:methods; D009602:Nitrosamines / Q000032:analysis*; D011145:Polyvinyls / Q000737:chemistry; D011312:Pressure; D015203:Reproducibility of Results; D012722:Sewage / Q000737:chemistry*; D052617:Solid Phase Microextraction / Q000379:methods; D053719:Tandem Mass Spectrometry; D013696:Temperature; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D004129:Dimethylpolysiloxanes; D009602:Nitrosamines; D011145:Polyvinyls; D012722:Sewage; D014874:Water Pollutants, Chemical; C445089:poly(dimethylsiloxane-divinylbenzene)