Determination of 4 Sterols in Atmospheric Particles by Ultrasonic Extraction Coupled with High Performance Liquid Chromatography-Tandem Mass Spectrometry

A rapid analytical method was developed for the determination of 4 sterols in atmospheric particles by ultrasonic extraction coupled with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). After extraction by methanol and enrichment, sterols were separated on an Atlantis C-18 column (100 mmx2.1 mm, 3 mu m) with acetonitrile and water served as mobile phase in gradient elution, then determined by HPLC-MS/MS using atmospheric pressure chemical positive ionization (APCI(+)) and multiple reaction monitoring (MRM). Parameters of chromatography and mass spectrometry, as well as conditions of ultrasonic extraction were optimized. The developed method provided good linearity (R > 0. 99) and high recoveries (80.3%-97.7%) for 4 sterols. Low detection limits were obtained as 0.015 ng/m(3), with RSD less than 15% (n = 6). Comparing with GC/MS, this method was more rapid, sensitive and economical because the derivation was eliminated from the procedure, thus saving a lot of resources. Samples of atmospheric particles were detected using this method, and the results indicated that this method could meet the requirements for quantitative analysis of sterols in atmosphere.