Two approaches to the removal of heating fuel oil trapped in wood and concrete: Bio- and photoremediation. Characterization of lignans in flaxseed by HPLC/DAD/ESI TOF MS and GC/MS.

摘要

Chemical contamination of buildings occurs as a result of storage, spills, and catastrophic floods. Over the time, contaminants slowly evaporate from the structural elements posing health risks. To develop a cost-effective and safe route to decontaminate and reuse the contaminated wood and concrete, studies including extraction of fuel oil hydrocarbons from wood and concrete, their transport and remediation were conducted.;n-Hexadecane was quantative recovered from wood using sequential extraction with acetone followed by pentane; from ambient concrete using pentane; and from water-saturated concrete using 2-propanol. Transport of fuel oil hydrocarbons in wood can be described by a two-step model: fast physical absorption of the liquid phase into the wood subsurface area followed by long-term contaminant diffusion through the bulk of the wood. Bioremediation resulted in 40--70% removal of n-hexadecane or fuel oil in 4--6 weeks whereas more than 95% of naphthalene was removed in just 1 week. Photoremediation resulted in >95% removal of n-hexadecane in just one week and about 50% of fuel oil in 1--2 weeks.;Flaxseed is known as one of the richest dietary sources of lignans, biologically active antioxidants that may help to cure cancer. Although, numerous lignan concentrations were reported, no systematic validation of the analytical methods was performed.;Thus, the sample preparation was optimized including the hydrolysis of pure diglucoside, liquid-liquid extraction and derivatization of hydrolyzed lignans with following gas chromatographic/mass spectrometric (GC/MS) analysis and solid-phase extraction with following high performance liquid chromatographic (HPLC)/MS analysis.;Only three lignan products were formed from the hydrolysis of the diglucoside. The sample extraction and purification methods play important role in the recoveries of the lignans. An 8h extraction with 80% methanol was required for optimal lignan recoveries. The purification using methylene chloride extraction was 2x more effective than when ethyl acetate/hexane mixture was used.;The limits of detections (LODs) for TOF MS (0.002--0.043 pg) were comparable to these of MS/MS (0.001--0.015 pg). GC/MS was the least sensitive (0.02--3.0 pg) of the methods, however the LODs obtained were two-fold lower than previously reported.;Concentrations of lignans in flaxseed hulls determined by the developed methods were comparable to each other. The total detected amount of SDG originally present in the analyzed flaxseed hulls was 5.5+/-1.0 mg/g of flaxseed hulls, which corroborates the literature data (2--26 mg/g flaxseed).