Details

Autor(en) / Beteiligte

• SUNG, NAK JUNE

Titel

PART I. INNOVATIVE GAS CHROMATOGRAPHIC TECHNIQUES FOR THE DETERMINATION OF VOLATILE POLAR ORGANICS AT THE PPB LEVEL IN AQUEOUS MATRICES. PART II. STUDY ON THE PREPARATION OF COPPER CAPILLARY COLUMNS FOR THE GAS CHROMATOGRAPHIC SEPARATION OF VOLATILE ORGANIC COMPOUNDS

Ort / Verlag

ProQuest Dissertations & Theses

Erscheinungsjahr

1986

Quelle

ProQuest Dissertations & Theses A&I

Beschreibungen/Notizen

• An extensive study on the quantitative determination of volatile polar and nonpolar organic compounds at 1 to 10 ppb range in aqueous matrices without any preconcentration has been carried out. The combination of new analytical developments such as direct injection of aqueous sample by on-column injection technique, bonded-phase fused silica capillary columns, and sensitive and selective gas chromatographic detectors was the main concept to determine trace organic compounds at 1- 10 ppb levels in various aqueous matrices. Flame ionization detector (FID), electron capture detector (ECD), photoionization detector (PID), and Far UV detector were evaluated for their working detectability and compatability with the aqueous sample. Bonded-phase fused silica capillary columns of Carbowax as a polar stationary phase and methyl silicone as a nonpolar stationary phase were examined for their column performance and suitability in handling aqueous samples. Among the six test compounds tested, volatile polar organics could not be determined satisfactorily on methyl silicone columns of a thin film in the 0.33 to 1 (mu)m range. Benzene, and methyl isobuthyl ketone (MIBK) were, however, excellently determined on these thin columns coupled with a FID down to 10 ppb level upon injection of 1 (mu)l of water sample. The detection limit of trichloroethylene (TCE) was not good compared to those of benzene and MIBK. The quantitative determination of volatile polar organics such as acetone, methyl ethyl ketone (MEK), and tetrahydrofuran (THF), could be achieved when using a 50 m long methyl silicone bonded-phase column with film thickness of 5 mm with the detection limits down to 5 ppb levels. All of the six test compounds could be determined quantitatively with base line separation on this thick column. The reproducibility of retention time for all components at 20 ppb level was within 2.3% of relative standard deviation for ten replicate injections of 1 (mu)l of water sample. The detection limit for all these components was lowered to 5 ppb level when injecting up to 5 (mu)l. Difficulties in quantitation of benzene and MIBK at 20 ppb level were due to the integrator being incapable for the precise integration of relatively wide peak widths. TCE at 20 ppb level was not quantitated because the minium detectable limit of TCE was down to 20-30 ppb level with S/N ratio of 2-3. Peak areas were reproducible within 20% of relative error for acetone, TCE, and benzene at 20 ppb level, while MIBK and TCE were reproducible within 40% and 70%, respectively.