Polyaniline/chitosan functionalized melamine sponge for quick, easy, cheap, effective, rugged, and safe analysis of quinolones in cosmetic emulsion by HPLC-fluorescence detection

Using cosmetics with prohibited quinolones can induce a range of deleterious side effects. The present study used polyaniline/chitosan functionalized melamine sponge (PANi@CS-Ms) as a novel and cost-effective QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) pretreatment material, in combination with high performance liquid chromatography-fluorescence detector (HPLC-FLD), for simultaneous and rapid detection of 5 quinolones (fleroxacin, levofloxacin, pefloxacin, enrofloxacin, and difloxacin) in cosmetic emulsions. The prepared PANi@CS-Ms was characterized using scanning electron microscopy, Fourier transform infrared spectra, X-ray photoelectron spectroscopy, thermogravimetric analysis, and water contact angle measurement. The results of quantitative determination demonstrated that the CS-assisted modification route achieved a significant increase of PANi loading compared with PANi-Ms. To achieve the optimal matrix removal and extraction efficiencies, several factors were optimized, including the weight of PANi@CS-Ms, type, volume, and acidity of the extraction solvent, and salt combinations. The matrix removal efficiency of PANi@CS-Ms surpassed that of raw Ms, CS-Ms, and PANi-Ms. The constructed analytical method showed a good linear relationship within a concentration range from 0.2 to 20 ng mL^-1, with a coefficient of determination greater than 0.999. The recoveries for all five quinolones fell between 78.4% and 103.9% at three different spiked concentrations. In terms of precision, the intra-day and inter-day relative standard deviations were found to be below 4.5% and 8.8%, respectively. This study demonstrated that PANi@CS-Ms can serve as an alternative to QuEChERS purification materials, thereby offering a novel direction for detecting prohibited drugs in cosmetics.