Evaluation of natural crab shell as an adsorbent for preconcentrating airborne volatile organic compounds collected in a canister

A method has been developed for preconcentrating the volatile organic compo unds (VOCs) in ambient air using a trap filled with natural crab shell powd er without the need for extensive cryotrapping with liquid cryogens. Air sa mples collected in the canister were concentrated on the crab shell adsorbe nt trap without cryotrapping and then analysed using thermal desorption fol lowed by capillary column (DB-5) gas chromatography with simultaneous ion t rap mass detection. These analytical data on ambient air have been compared with those obtained by cryotrapping volatile compounds in glass beads foll owed by thermal desorption. The characteristics of natural crab shell as an adsorbent have been presented and its capacity for preconcentrating airbor ne VOCs has been tested by measuring breakthrough volume (l/g), detection l imit (ppb, v/v) and reproducibility. The application of natural crab shell adsorbent trap for the analysis of ambient air samples collected in the can ister has been proved to be useful. (C) 1998 Elsevier Science B.V. All righ ts reserved.