Abstract: A matrix solid-phase dispersion extraction (MSPDE) method was developed to extract 6 tetracycline antibiotics (TCs) from milk samples using multiwalled carbon nanotubes (MWCNTs) as adsorbent prior to high performance liquid chromatography (HPLC) determination. Milk samples, MWCNTs, oxalic acid, and EDTA were evenly ground and then packed into a glass syringe as dispersion column. The analytes were eluted with methanol containing formic acid, and detected by HPLC with variable wavelength detector at 365 nm. The limits of detection (LODs) for 6 TCs ranged from 0.01 to 0.03μg/mL. Their recoveries in spiked milk samples were in the range of 78.7%－105.2% with relative standard deviations of less than 12%. #br# MSPD exhibited higher recovery in extracting 6 TCs as compared to C18 column extraction, suggesting that the developed MSPD procedure can be applied for the multiresidues analysis of pesticides and veterinary drugs in foods.

Key words: tetracycline antibiotics, matrix solid-phase dispersion extraction, carbon nanotubes, high performance liquid chromatography