Component loss during evaporation—reconstitution of organic environmental samples for gas chromatographic analysis

Abstract

Standard and sample solutions stored in borosilicate sample vials were allowed to evaporate to dryness at room temperature. The solutins were analyzed by gas chromatography—flame ionization detection before evaporaion and after reconstitution to the original volume to determine component losses due to evaporation. The standard solutions were also stored in sample vials which had been treated with a surface deactivating agent, benzyltriphenylphosphonium chloride. The standard solution contained n-hydrocarbons, l-alcohols, phthalates and polynuclear aromatic hydrocarbons. The sample solution was a benzene extrat of municipal incinerator fly-ash which contained over 200 components including n-hydrocarbons, phthalates, polynuclear aromatic hydrocarbons and polychlorinated dibenzo- p-dioxins. At the 95% confidence level, the differences among mean losses observed with the 100 ng/μl standard mixture were within random variations between untreated and deactivated vials. The random variations between mean losses of the 10 ng/μl mixture were significantly higher with the deactivated vials at the 99% confidence level. Large losses were observed for early-eluting components of the standard solutions and the benzene extract of incinerator fly ash. Losses for polychlorinated benzo- p-dioxins and polynuclear aromatic hydrocarbons averaged ca. 10%.