title: Development of a syringe pump assisted dynamic headspace sampling technique for needle trap device.
abstract: This paper describes a new approach that combines needle trap devices (NTDs) with a dynamic headspace sampling technique (purge and trap) using a bidirectional syringe pump. The needle trap device is a 22-G stainless steel needle 3.5-in. long packed with divinylbenzene sorbent particles. The same sized needle, without packing, was used for purging purposes. We chose an aqueous mixture of benzene, toluene, ethylbenzene, and p-xylene (BTEX) and developed a sequential purge and trap (SPNT) method, in which sampling (trapping) and purging cycles were performed sequentially by the use of syringe pump with different distribution channels. In this technique, a certain volume (1 mL) of headspace was sequentially sampled using the needle trap; afterwards, the same volume of air was purged into the solution at a high flow rate. The proposed technique showed an effective extraction compared to the continuous purge and trap technique, with a minimal dilution effect. Method evaluation was also performed by obtaining the calibration graphs for aqueous BTEX solutions in the concentration range of 1-250 ng/mL. The developed technique was compared to the headspace solid-phase microextraction method for the analysis of aqueous BTEX samples. Detection limits as low as 1 ng/mL were obtained for BTEX by NTD-SPNT.
authors.affiliation: Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada.
authors.forename: In-Yong
authors.initials: IY
authors.lastname: Eom
authors.forename: Vadoud H
authors.initials: VH
authors.lastname: Niri
authors.forename: Janusz
authors.initials: J
authors.lastname: Pawliszyn
mesh_terms: D001555:Benzene Derivatives / Q000737:chemistry; D005591:Chemical Fractionation / Q000295:instrumentation* / Q000379:methods; D002849:Chromatography, Gas; D009339:Needles; D015203:Reproducibility of Results; D013696:Temperature; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000737:chemistry
chemical_list: D001555:Benzene Derivatives; D014874:Water Pollutants, Chemical