title: Determination of aromatic hydrocarbons in asphalt release agents using headspace solid-phase microextraction and gas chromatography-mass spectrometry.
abstract: The possibility of quantitative analysis of aromatic hydrocarbons in oil-based asphalt release agents was investigated using headspace solid-phase microextraction (HS-SPME) followed by gas chromatography-mass spectrometry (GC-MS). The target analytes studied were benzene, toluene, ethylbenzene, p-, m-, and o-xylene (BTEX) and 1,3,5-trimethylbenzene and 1,2,4-trimethylbenzene. Experimental parameters influencing HS-SPME efficiency were studied (equilibration time between sample and headspace and between headspace and SPME fiber, sample amount and sample matrice effects). A HS-SPME method using hexadecane as a surrogate matrice was developed. The detection limit was estimated as 0.03-0.08 ppm (w/w) for the target analytes investigated. Good linearity was observed (R2 > 0.999) for all calibration curves at high, medium and low concentration level. The repeatability of the method (RSD, relative standard deviation) was found to be less than 10% (generally less than 5%) in triplicate samples and approximately 2% at eight consecutive tests on one and the same sample. The accuracy of the method given by recovery of spiked samples was between 85 and 106% (generally between 95 and 105%). The HS-SPME method developed was applied to four commercially available asphalt release agents. External calibration and standard addition approaches were investigated regarding accuracy. The results showed that standard addition generates higher accuracy than external calibration. The contents of target aromatic hydrocarbons in the asphalt release agents studied varied greatly from approximately 0.1-700 ppm. The method described looks promising, and could be a valuable tool for determination of aromatic hydrocarbons in different types of organic matrices.
authors.affiliation: Department of Civil and Architectural Engineering, Royal Institute of Technology, SE-10044 Stockholm, Sweden.
authors.forename: Bing
authors.initials: B
authors.lastname: Tang
authors.forename: Ulf
authors.initials: U
authors.lastname: Isacsson
mesh_terms: D001554:Benzene / Q000302:isolation & purification; D001555:Benzene Derivatives / Q000302:isolation & purification; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D006838:Hydrocarbons / Q000737:chemistry*; D006841:Hydrocarbons, Aromatic / Q000032:analysis*; D015203:Reproducibility of Results; D014050:Toluene / Q000302:isolation & purification; D014992:Xylenes / Q000302:isolation & purification
chemical_list: D001555:Benzene Derivatives; D006838:Hydrocarbons; D006841:Hydrocarbons, Aromatic; D014992:Xylenes; D014050:Toluene; C006647:asphalt; D001554:Benzene; C004912:ethylbenzene