Analysis of trace levels of sulfonamides in fish tissue using micro-scale pipette tip-matrix solid-phase dispersion and fast liquid chromatography tandem mass spectrometry.

A micro-scale matrix solid-phase dispersion (MSPD) technique, using hydrophilic-lipophilic balance (HLB) material as sorbent and a pipette tip (PT) as the cartridge, was developed for the extraction and purification of sulfonamides in fish tissue. Eluates from PT-MSPD were analyzed using fast liquid chromatography and tandem mass spectrometry (LC-MS/MS). The method was fully validated; good linearity was obtained with correlation coefficients greater than 0.99. Precision and accuracy (RSD%) were in the range 1.4-10.3% while mean recoveries were 70.6-95.5%. With this technique, 15 aquatic samples (Collichthys niveatus) were analyzed for sulfonamides. The whole procedure took only 13min (5min for PT-MSPD and 8min for LC), materials for each sample included 5.1mL solvents (0.3mL for PT-MSPD and 4.8mL for LC), and 20mg HLB sorbent. Generally speaking, this method is indeed practical and particularly suitable for widespread drug residue analysis.