Simultaneous trace determination of acidic non-steroidal anti-inflammatory drugs in purified water, tap water, juice, soda and energy drink by hollow fiber-based liquid-phase microextraction and ultra-high pressure liquid chromatography coupled to tandem mass spectrometry.

In this study, a two-phase hollow fiber liquid-phase microextraction (HF-LPME) coupling with ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed for determination of four non-steroidal anti-inflammatory (NSAIDs)-salicylic acid, ibuprofen, naproxen and diclofenac in real water samples. The influencing parameters of HF-LPME sample preparation method, such as organic solvents (acceptor phase), pH of sample solution (donor phase), extraction time, stirring speed, extraction temperature and ionic strength were systematically optimized. Through the developed determination method, high enrichment factors (195-346) were achieved for the four drugs. The instrumental calibration curves of salicylic acid, naproxen, diclofenac, and ibuprofen show good linear relations (R>0.998) in the concentration range of 1-500, 5-2500, 10-5000 and 5-2500 μg L(-1), respectively. The average recoveries of the four drugs in the low, medium and high spiked concentration levels (20-200, 50-500 and 100-1000 μg L(-1)) were between 98-115% with relative standard deviation (RSD) values were less than 12% (n=6). Limits of detection (LOD) of salicylic acid, naproxen, diclofenac, and ibuprofen in water were 0.5, 0.5, 1.0, and 1.25 μg L(-1), respectively. The determination method has been applied for the real samples (purified water, tap water, juice, soda and energy drinks), and the results show that salicylic acid was detected in tap water and soda, the concentrations were 2.85 μg L(-1) and 61.22 μg L(-1) separately, the RSD values were less than 9% (n=6). Salicylic acid and diclofenac were detected in energy drink, the concentrations were 44.62 μg L(-1) and 8.31 μg L(-1), the RSD values were less than 11% (n=6).