Hollow-fiber liquid-phase microextraction (HF-LPME) has been developed for preconcentration of macrolide antibiotic residues in water and poultry muscle. A low-cost microporous hollow fiber was employed with simple configuration for enrichment process. HF-LPME parameters affecting enrichment factor such as immersion time, organic solvent composition, donor solution, acceptor solution and extraction time were investigated. A few microliters of 20% Aliquat 336 in dihexylether immersed in the hollow fiber pores have induced the extraction and preconcentration of four macrolide antibiotics from outside (donor solution pH 8.0) to inside (acceptor solution pH 4.0) fiber membrane within 60 minutes of extraction time, qualitative and quantitative detection with liquid chromatography-tandem mass spectrometry. In selected HF-LPME condition, macrolide antibiotics can preconcentrated with enrichment factor between 12.38 to 36.14 at concentration 50.00 µg/L. Limit of detection ranged from 0.07 to 2.28 µg/L with correlation coefficient between 0.97 to 0.99 in concentration range of 0.50-5.00 µg/L, the high value of % recovery ranged from 89.90 to 102.99 and the relative standard deviations were in acceptable range (<1.35) when compared with the value from Horwitz equation. This method was effectively applied in real sample with enrichment factor of four macrolides ranged from 14.15 to 35.81 for water sample and 3.94 to 7.31 for poultry sample. The % recoveries of macrolides from water and poultry sample were high in range of 82.93 to 97.20 and 71.78 to 90.23, respectively.

Thesis (M.Sc.)--Chulalongkorn University, 2009