A GC-MS method for the determination of polar organic compounds in atmospheric samples

A new method was developed for the simultaneous determination of polar organic compounds from liquid samples (atmospheric hydrometeors) as well as for aerosol samples. The analysis of aerosol samples includes a new extraction method using diethylether, methanol and organic free water to obtain a liquid sample solution. The sample-separation into two classes of organic compounds with different polarity was performed using solid phase extraction (SPE). The adsorbed fraction contains weakly polar compounds like monocarboxylic acids (C8 - C18), alcohols (Cg - C18), phthalates, aliphatic and aromatic aldehydes. The solution passing the SPE-tube contains the not adsorbed strong polar organic compounds like dicarboxylic acids (C2 - C9) and related compounds. After a sample pretreatment of the two fractions, including esterification of the acids and extraction with cyclohexane, the samples were analyzed with GC-MS. Recoveries for the determined compounds ranged from 60 - 100%, the experiments have shown that substances with longer carbon chains exhibit decreased recoveries. The reproducibility given as the relative standard deviation varies from 5 - 15%. The absolute amount of an individual compound which is necessary for detection is about 10 to 50 ng. For quantification the absolute amounts varies in a range of 25 to 150 ng. The new method is applied for the analysis of aerosol and cloud water samples from a continental background site in Central Europe (Sonnblick Observatory).