Sains Ma1aysiana 28: 119-126 (1999)                                                                          Sains Fizis dan Gunaan/

                                                                                                                                                Physical and Applied Science

The Use of Solid Phase Microextraction Technique for the

Extraction of Trihalomethanes in Drinking Water

Md. Pauzi Abdullah & Aiman M. Bobaker

Jabatan Kimia, Fakulti Sains Fizis dan Gunaan

Universiti Kebangsaan Malaysia

43600 UKM Bangi Selangor D.E. Malaysia

ABSTRACT

Solid phase micro-extraction technique is a fast, sensitive, inexpensive, portable and solvent free method for extracting organic compounds from aqueous samples. This technique involves exposing a fused silica fibre that has been coated with a stationary phase to an aqueous solution containing organic contaminants. The analytes partition into the stationary phase until an equilibrium has been reached, after which the fibre is removed from the solution and the analytes are thermally desorbed into the injector of a gas chromatograph. Optimization work were carried out for the time of absorption and desorption, and the equilibrium temperatures for the extraction of trihalomethanes in drinking water samples. Almost 100% recovery was achieved within three minutes of equilibration between 25 to 30°C with desorption time of two minutes. The samples of drinking water supplies were analyzed against calibrated standard solutions in deionized water. With 20.0 ml water sample, the method's detection limit MDL of 0.01 ppb was achieved for CHCl₃ and CHBrCI_2. For CHBr₂Cl and CHBr₃ the MDL were 0.04 and 0.06 ppb, respectively.

ABSTRAK

Teknik pengekstrakan mikro fasa pepejal ialah satu teknik pengekstrakan sebatian organik yang cepat, peka, murah dan bebas pelarut. Teknik ini melibatkan pencelupan gentian silika terlakur yang dilapisi dengan suatu fasa pegun ke dalam larutan yang mengandungi pencemar organik. Analit organik akan terjerap kepada gentian sehingga mencapai keseimbangan. Gentian yang mengandungi organik terjerap dikeluarkan daripada larutan dan kemudiannya dinyahjerap di dalam penyuntik alat kromatografi gas. Teknik ini telah dioptimumkan dari segi masa jerapan, masa nyahjerapan dan suhu keseimbangan. Hampir 100% pemulihan dicapai dengan masa keseimbangan selama 3 minit pada suhu antara 25°C ke 30°C dan dengan masa nyahjerap selama 2 minit. Analisis ke atas beberapa sampel air minum telah dilakukan menggunakan teknik ini. Bagi isipadu sampel sebanyak 20.0 ml, had pengesanan kaedah serendah 0.01 ppb telah dicapai bagi komponen CHCI₃ dan CHBrCI₂. Bagi CHBr₂Cl dan CHBr₃, had pengesanan kaedah masing-masingnya ialah 0.04 dan 0.06 ppb.

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