title: Exploring petroleum hydrocarbons in groundwater by double solid phase extraction coupled to gas chromatography-flame ionization detector.
abstract: This work proposes an analytical procedure for measuring aliphatic and aromatic hydrocarbons fractions present in groundwater. In this method, hydrocarbons are solid phase extracted (SPE) twice from the groundwater and the resulting fractions are analyzed by gas chromatography with flame ionization detection. The first SPE disposes the hydrocarbons present in groundwater in organic solvents and the second SPE divides them into aliphatic and aromatic hydrocarbons. The validation study is carried out and its uncertainties are discussed. Identifying the main sources of uncertainty is evaluated through applying the bottom-up approach. Limits of detection for hydrocarbons ranges are below 5 µg L(-1), precision is not above of 30%, and acceptable recoveries are reached for aliphatic and aromatic fractions studied. The uncertainty due to volume of the sample, factor of calibration and recovery are the highest contributions. The expanded uncertainty range from 13% to 26% for the aliphatic hydrocarbons ranges and from 14% to 23% for the aromatic hydrocarbons ranges. As application, the proposed method is satisfactorily applied to a set of groundwater samples collected in a polluted area where there is evidence to present a high degree of hydrocarbons. The results have shown the range of aliphatic hydrocarbons >C21-C35 is the most abundant, with values ranging from 215 µg L(-1) to 354 µg L(-1), which it is associated to a contamination due to diesel.
authors.affiliation: Division of Chemistry, Technology Department, CIEMAT. Av. Complutense 40, 28040 Madrid, Spain. Electronic address: oscar.pindado@ciemat.es.
authors.forename: Oscar
authors.initials: O
authors.lastname: Pindado Jiménez
authors.affiliation: Division of Chemistry, Technology Department, CIEMAT. Av. Complutense 40, 28040 Madrid, Spain.
authors.forename: Rosa Ma
authors.initials: RM
authors.lastname: Pérez Pastor
authors.affiliation: Division of Soil and Environmental Geology, Environment Department, CIEMAT. Av. Complutense 40, 28040 Madrid, Spain.
authors.forename: Olga
authors.initials: O
authors.lastname: Escolano Segovia
authors.affiliation: Environment and Hydrogeology, AITEMIN. C/Río Cabriel, 45007 Toledo, Spain.
authors.forename: Susana
authors.initials: S
authors.lastname: del Reino Querencia
mesh_terms: D002849:Chromatography, Gas / Q000379:methods*; D005410:Flame Ionization / Q000379:methods; D060587:Groundwater / Q000032:analysis*; D006840:Hydrocarbons, Alicyclic / Q000032:analysis*; D006841:Hydrocarbons, Aromatic / Q000032:analysis*; D010578:Petroleum / Q000032:analysis*; D052616:Solid Phase Extraction / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D006840:Hydrocarbons, Alicyclic; D006841:Hydrocarbons, Aromatic; D010578:Petroleum; D014874:Water Pollutants, Chemical
keywords: Groundwater; Hydrocarbons fractions; Petroleum hydrocarbons; Solid phase extraction; Uncertainty; Validation