Extraction of bituminous coal fly ash for polynuclear aromatic hydrocarbons: evaluation of modified and unmodified supercritical fluid extraction, enhanced fluidity solvents, and accelerated solvent extraction.
A comparison among supercritical fluid extraction (SFE), modified SFE, enhanced-fluidity extraction, and accelerated solvent extraction (ASE) techniques was made for the extraction of polynuclear aromatic hydrocarbons (PAHs) from an aged, spiked bituminous coal fly ash. Non-ASE extraction techniques used in this study could not recover PAHs with molecular weights greater than that of pyrene. ASE techniques using methylene chloride (with and without a static step) and toluene were able to recover most of the PAHs studied. None of the ASE techniques could quantitatively extract the low-molecular-weight PAHs from the bituminous fly ash. The medium-molecular-weight PAHs were best recovered with toluene ASE. The high-molecular-weight PAHs were best recovered with the toluene ASE technique (> 80%), but the overall precision of these measurements was low. Methylene chloride ASE with a static step recovered the high-molecular-weight PAHs with the next highest efficiency (approximately 55%) and had standard deviations less than 10% (longer extraction times [> 30 min] with the methylene chloride would increase the recoveries of these analytes.) A comparison of the results from this study with those of a previous study using lignite coal fly ash illustrates the difficulty in developing and adapting analyte-specific extraction methods for analytes that are adsorbed on different matrices.
Kenny
D V
DV
Department of Chemistry, Ohio State University, Columbus 43210, USA.
Olesik
S V
SV
D002244:Carbon / Q000032:analysis / Q000737:chemistry*; D003031:Coal / Q000032:analysis; D060729:Coal Ash; D006841:Hydrocarbons, Aromatic / Q000032:analysis* / Q000737:chemistry; D007220:Industrial Waste / Q000032:analysis; D008752:Methylene Chloride / Q000737:chemistry; D008970:Molecular Weight; D052638:Particulate Matter; D015203:Reproducibility of Results; D012997:Solvents / Q000737:chemistry; D014050:Toluene / Q000737:chemistry
D003031:Coal; D060729:Coal Ash; D006841:Hydrocarbons, Aromatic; D007220:Industrial Waste; D052638:Particulate Matter; D012997:Solvents; D014050:Toluene; D008752:Methylene Chloride; D002244:Carbon