A multiresidue method for the analysis of phenols and nitrophenols in the atmosphere

Abstract

A method using GC-MS and derivatization with N-(t-butyldimethylsilyl)-N-methyltrifluoroacetamide (MTBSTFA) was developed for the analysis of 20 phenolic compounds in atmospheric samples (gas and particles). Air sampling was carried out using a Hi-Vol sampler with glass fibre filter and XAD-2 resin at a flow rate of 60 m³ h⁻¹. The particle and gas phases were collected separately over a period of 4 h. Samples were Soxhlet extracted, evaporated to dryness under nitrogen and refilled with acetonitrile. 100 μl of these extracts were derivatized with 100 μl of MTBSTFA at 80 °C for 1 h under strong stirring. Phenolic compounds were injected into a GC–MS in splitless mode and quantified as their TBDMS derivatives in the SIM mode. Mass spectral analysis of the derivatives of the 20 compounds studied indicates that the spectra are highly specific showing an ion at [M − 57]⁺ which is useful for structure confirmation or analysis at low levels using selected ion monitoring. Quantification limits varied between 5 μg l⁻¹ and 10 μg l⁻¹ which correspond to 20 pg m⁻³ and 40 pg m⁻³ for 250 m³ of air sampled. This method was successfully applied to atmospheric samples.