A simple, rapid, and sensitive method is developed for the determination of UV filters in river waters by applying the vortex-assisted dispersive liquid-liquid microextraction based on solidified floating organic droplet technique followed by the injector port silylation (IPS) in a gas chromatography-tandem mass spectrometry system. Statistical experimental design methods including general factorial design, one factor at a time, and central composite face-centered design are used for optimization purposes. Under optimized conditions, 460 mu L of acetone and 30 mu L of 2-dodecanone are rapidly injected into a 10 mL water sample with 10% (w/v) NaCl at pH 2.5 and vortexed for 3 min. After centrifugation, 2 mu L of the separated organic solvent is subjected to auto-IPS with 1 mu L of bis (trimethylsilyl) trifluoroacetamide containing 1% trimethylchlorosilane, at 260 degrees C for 4.5 min in programmable temperature vaporization mode. As a result of the validation studies, the intra-day and inter-day precision indicated as relative standard deviation are less than 12.4% and 18.8%, respectively. For all UV filters, detection limits are between 1.1 and 5.5 ng L-1 and limit of quantitation values are between 3.1 and 16.6 ng L-1. Successful recovery of extraction values (77.1%-107.4%) and good enrichment factors (231-350) are obtained.