title: Matrix effect on the performance of headspace solid phase microextraction method for the analysis of target volatile organic compounds (VOCs) in environmental samples.
abstract: Solid phase microextraction (SPME) is a fast, cheap and solvent free methodology widely used for environmental analysis. A SPME methodology has been optimized for the analysis of VOCs in a range of matrices covering different soils of varying textures, organic matrices from manures and composts from different origins, and biochars. The performance of the technique was compared for the different matrices spiked with a multicomponent VOC mixture, selected to cover different VOC groups of environmental relevance (ketone, terpene, alcohol, aliphatic hydrocarbons and alkylbenzenes). VOC recovery was dependent on the nature itself of the VOC and the matrix characteristics. The SPME analysis of non-polar compounds, such as alkylbenzenes, terpenes and aliphatic hydrocarbons, was markedly affected by the type of matrix as a consequence of the competition for the adsorption sites in the SPME fiber. These non-polar compounds were strongly retained in the biochar surfaces limiting the use of SPME for this type of matrices. However, this adsorption capacity was not evident when biochar had undergone a weathering/aging process through composting. Polar compounds (alcohol and ketone) showed a similar behavior in all matrices, as a consequence of the hydrophilic characteristics, affected by water content in the matrix. SPME showed a good performance for soils and organic matrices especially for non-polar compounds, achieving a limit of detection (LD) and limit of quantification (LQ) of 0.02 and 0.03 ng g(-1) for non-polar compounds and poor extraction for more hydrophilic and polar compounds (LD and LQ higher 310 and 490 ng g(-1)). The characteristics of the matrix, especially pH and organic matter, had a marked impact on SPME, due to the competition of the analytes for active sites in the fiber, but VOC biodegradation should not be discarded in matrices with active microbial biomass.
authors.affiliation: Department of Soil and Water Conservation and Organic Waste Management, Centro de Edafología y Biología Aplicada del Segura, CSIC, PO Box 4195, 30080 Murcia, Spain; Department of Soil Science, Federal University of Lavras, Department of Soil Science , PO Box 3037, 37200-000 Lavras, Minas Gerais, Brazil.
authors.forename: Fábio S
authors.initials: FS
authors.lastname: Higashikawa
authors.forename: Maria Luz
authors.initials: ML
authors.lastname: Cayuela
authors.forename: Asunción
authors.initials: A
authors.lastname: Roig
authors.forename: Carlos A
authors.initials: CA
authors.lastname: Silva
authors.forename: Miguel A
authors.initials: MA
authors.lastname: Sánchez-Monedero
mesh_terms: D004784:Environmental Monitoring / Q000379:methods*; D004785:Environmental Pollutants / Q000032:analysis* / Q000737:chemistry; D052617:Solid Phase Microextraction / Q000379:methods*; D055549:Volatile Organic Compounds / Q000032:analysis* / Q000737:chemistry
chemical_list: D004785:Environmental Pollutants; D055549:Volatile Organic Compounds
keywords: Biochar; Limit of detection; Limit of quantification; Organic wastes; SPME; Soil