title: Application of microwave-assisted desorption/headspace solid-phase microextraction as pretreatment step in the gas chromatographic determination of 1-naphthylamine in silica gel adsorbent.
abstract: Pretreatment of silica gel sample containing 1-naphthylamine by microwave-assisted desorption (MAD) coupled to in situ headspace solid phase microextraction (HS-SPME) has been investigated as a possible alternative to conventional methods prior to gas chromatographic (GC) analysis. The 1-naphthylamine desorbs from silica gel to headspace under microwave irradiation, and directly absorbs onto a SPME fiber located in a controlled-temperature headspace area. After being collected on the SPME fiber, and desorbed in the GC injection port, 1-naphthylamine is analyzed by GC-FID. Parameters that influence the extraction efficiency of the MAD/HS-SPME, such as the extraction media and its pH, the microwave irradiation power and irradiation time as well as desorption conditions of the GC injector, have been investigated. Experimental results indicate that the extraction of a 150mg silica gel sample by using 0.8ml of 1.0M NaOH solution and a PDMS/DVB fiber under high-powered irradiation (477W) for 5min maximizes the extraction efficiency. Desorption of 1-naphthylamine from the SPME fiber in GC injector is optimal at 250 degrees C held for 3min. The detection limit of method is 8.30ng. The detected quantity of 1-naphthylamine obtained by the proposed method is 33.3 times of that obtained by the conventional solvent extraction method for the silica gel sample containing 100ng of 1-naphthylamine. It provides a simple, fast, sensitive and organic-solvent-free pretreatment procedure prior to the analysis of 1-naphthylamine collected on a silica gel adsorbent.
authors.affiliation: Department of Occupational Safety and Health, Chung-Shan Medical University, Taichung 402, Taiwan.
authors.forename: Cheing-Tong
authors.initials: CT
authors.lastname: Yan
authors.forename: Jen-Fon
authors.initials: JF
authors.lastname: Jen
authors.forename: Tung-Sheng
authors.initials: TS
authors.lastname: Shih