Abstract: A quantitative and qualitative method of ultrasound-extraction high performance liquid chromatography coupled precolumn derivation with ultrasound was developed for the rapid and sensitive analysis of formaldehyde in wollens sample.The wollens were extracted by 0.1% sodium dodecyl ?sulfate solution under ultrasonic for 15min at 30 ℃, then 0.03% DNPH solution prepared with acetonitrile-phosphate buffer (pH=2) as the derivatization reagent, the ultrasonic assisted derivatizations were processed for 15 min. The formaldehyde derivatives were separated on an SunFireTMC18柱（4.6 nm×150 nm, 5μm）at 30 ℃ with acetonitrile-water ( 60:40，v /v) as mobile phase at a flow rate of 1.0 mL/min，and detected at the wavelength of 350 nm．The recoveries were 81.36~109.80% at the spiked levels of 10, 50, 150mg /kg of formaldehyde in wollens，and the relative standard deviations were less than 10. 0%, the limit of quantification of the formaldehyde in wollens was ≤5.0mg/kg．This method had the advantages of less time of pretreatment, simpler handle, better repeatability and higher accuracy than tradition methods.

Key words: formaldehyde, ultrasonic extraction, high performance liquid chromatography, pre-column derivatization