Gas chromatographic determination of formaldehyde in air using solid-phasemicroextraction sampling

The optimization of in situ derivatization and preconcentration of formalde hyde in air using solid phase microextraction with gas chromatographic dete rmination was investigated. A dimethylpolysiloxane coating (7 mu m) solid-p hase microextraction needle was used in the final procedure as a support fo r derivatizing reagents such as 2,4-dinitrophenylhydrazine and acetylaceton e. Standard concentrations of formaldehyde in air were obtained using a hea dspace technique and equilibrium concentrations of formaldehyde in air were calculated using Henry's law. After derivatization on the fiber, the deriv ative was thermally desorbed in the injector of a gas chromatograph and ana lyzed using an electron capture detector. A detection limit of 0.17 mg m(-3 ) was obtained. Calibration was done at 296 K. Reproducibility of the metho d was 9.6 %. Some real air samples were also analyzed. The method is very c onvenient and ideal for the rapid determination of formaldehyde in air.