[Determination of seven non-selective cyclooxygenase inhibitors in milk powder by ultra-performance liquid chromatography-tandem mass spectrometry with dispersive solid phase extraction].

An ultra-performance liquid chromatography-tandem mass spectrometry with dispersive solid phase extraction (dSPE-UPLC-MS/MS) method was developed to determine seven non-selective cyclooxygenase inhibitors in milk powder. The samples were extracted with 0.01 mol/L pH 2.5 ascorbic acid-acetonitrile-ethyl acetate solution (2:5:5, v/v/v), and then purified with a mixture of anhydrous sodium sulfate, octadecyl carbon silica gel (C18-N) sorbent and ethylenediamine-N-propyl carbon silica gel (NH2-PSA) sorbent. The analysis was performed using a UPLC-MS/MS system with Waters CORTECS UPLC C18 (100 mm×2.1 mm, 1.6 µm) column. The mobile phase consisted of 0.1% (v/v) formic acid aqueous solution and acetonitrile containing 0.1% (v/v) formic acid by gradient elution, and the multiple reaction monitoring (MRM) mode was used. Five linear calibration curves were obtained with correlation coefficients (r2) ≥ 0.9965. The recoveries were determined at three spiked levels and ranged from 76.4% to 89.8%. The limits of quantification (LOQs) were from 2 to 5 µg/kg. This method is suitable for the determination of seven non-selective cyclooxygenase inhibitors in milk powder.

[Simultaneous rapid determination of 12 anti-allergic chemical drugs in Chinese traditional patent medicine and health food by supercritical fluid chromatography tandem mass spectrometry with solid phase extraction].

An analytical method was developed for simultaneous rapid determination of 12 anti-allergic chemical drugs in Chinese traditional patent medicine and health food by supercritical fluid chromatography tandem mass spectrometry with solid phase extraction (SPE-SFC-MS/MS). Samples were extracted with methanol by sonification and then purified by Oasis mixed-model cation exchange SPE. The extracts were separated on a Waters Trefoil CEL1 (150 mm×3.0 mm, 2.5 µ m) column with a mobile phase consisting of carbon dioxide-methanol containing 0.1% (v/v) ammonia water in a gradient elution mode, at a flow rate of 1.2 mL/min. The column temperature was 45℃ and the back pressure was 12.4×106 Pa. The whole analysis was completed in 10 min. The 12 anti-allergic chemical drugs were detected by an electrospray ion source in positive or negative modes with a multiple reaction monitoring (MRM) mode. The calibration curves of the 12 anti-allergic chemical drugs showed good linearities in the range of 5-250 µ g/L with the correlation coefficients (r) ≥ 0.998. The limits of detection (LODs) were 0.141-0.262 µ g/L, and the limits of quantification (LOQs) were 0.703-1.308 µ g/L. The recoveries of the 12 anti-allergic chemical drugs at spiked levels of 10, 20 and 100 µ g/L were in the range of 76.1%-112.5%, and the relative standard deviations (RSDs) were 1.1%-8.3% (n=6). The method is simple, sensitive and reliable. It has been successfully used for the detection of illegally added anti-allergic chemical drugs in Chinese traditional patent medicine and health food.