Fast quantification of fluoroquinolones in environmental water samples using molecularly imprinted polymers coupled with internal extractive electrospray ionization mass spectrometry

Abstract

In this study, a facile method based on molecularly imprinted polymers (MIPs) combined with internal extractive electrospray ionization tandem mass spectrometry (iEESI-MS/MS) was developed for the quantitative analysis of fluoroquinolones (FQs) in environmental water samples. FQ molecules in water samples were captured by the MIPs, which was retained on a 0.22 μm syringe filter. Then, an electrospray solution selected as the elution solution was employed to extract the FQs from the MIPs, getting an eluate of FQs for mass spectrometric interrogation. Under the optimized experimental conditions, low limits of detection (LODs, 0.015-0.026 μg L^-1), with relative standard deviations (RSDs) less than 8.81% (n = 6) were obtained. The present method also provides good recoveries (91.14-103.60%) with acceptable precision (RSDs < 6.18%) and have no serious matrix effects for environmental water samples. The experimental results demonstrated that MIPs-iEESI-MS/MS has advantages including easy use, high speed (less than 3 min per sample) and high sensitivity for the analysis of FQs in environmental water samples, showing potential application in environmental science and water safety control.

Fig. 1. Schematic illustration of MIPs-iEESI-MS for analysis of FQs.

Fig. 2. MIPs-iEESI-MS/MS spectra of FQs spiked in deionized water at the concentration of 10 μg L⁻¹. (a) Fleroxacin, (b) norfloxacin and (c) enoxacin.

Fig. 3. Optimization of the MIPs-iEESI-MS/MS experimental conditions: (a) amount of MIPs (b) composition of elution solution (c) volume of elution solution (d) flow rate of extraction and (e) mixture vortexes time. n = 6, the error bar represents a standard deviation of 6 determinations.

Fig. 4. Recoveries curves of inter-day. Spiked sample at the concentrations of 50 μg L⁻¹ (a), 15 μg L⁻¹ (b) and 0.5 μg L⁻¹ (c).