Determination Of Quinolones In Honey By Liquid Phase Microextraction Based On New Extraction Solvents

Quinolones（QNs）will survive through the accumulation of food chain and biological metabolism,forming veterinary drug residues and causing serious damage to human health.Therefore,in order to protect the health of consumers,it is imperative to strictly supervise veterinary drug residues,control and reduce their presence in food.Liquid phase microextraction（LPME）with advantages of simple operation,high enrichment ratio,low cost and good biocompatibility is widely applied in multiple fields.The noval extraction solvent has the unique properties of low toxicity,strong solubility,stable properties,adjustable structure and wide liquid path.It has become a hot topic in analytical chemistry and has great potential.This work aims to establish a liquid-phase microextraction method based on noval extraction solvent,which is used to detect QNs residues in honey samples and provide effective technical guarantee for monitoring drug residues.A novel vortex assisted dispersive liquid-liquid microextraction method based on deep eutectic solvent（VA-DLLME-DES）completed in syringe has been established to extract twelve quinolones from honey.This method is an improvement of traditional DLLME.In this work,the green DES prepared with heptanoic acid and thymol was used for extractant rather than traditional organic extraction solvent.Without centrifugation,the phases were separated in the way of removing aqueous phase by pushing the syringe and extractant phase was collected for Ultra performance liquid chromatography-mass spectrometry（UPLC-MS）analysis.The stability of DES and some experimental parameters（type,molar ratios and volume of extraction solvent,type and volume of dispersant,vortex time and effect of p H and Na Cl）were evaluated.In the range of 2-100 ng m L^-1,the proposed method showed good linearities（R~2 ranged from0.996 to 0.999）.The extraction recoveries were obtained in the range of 75.01%-117.05%and relative standard deviations were less than 13.83%for inter-（n=6）and intra-day（n=3）precisions.The limits of detection and quantification were 3 ng g-1 and 10 ng g-1,respectively.The developed method with the advantages of simple operation,short extraction time and less consumption organic solvent provides a technical idea for green,simple and time-saving sample preparation methods.In this work,nonanoic acid with switchable and lower density than water was used as extractant to establish an effervescent assist liquid phase microextraction（EA-LPME）based on switchable hydrophilic solvent combined with high performance liquid chromatography with fluorescence detection（HPLC-FLD）method for the determination of seven quinolones in honey.In the proposed method,the p H value of the solution was adjusted by adding Na₂CO₃and H₂SO₄ separately to promote nonanoic acid complete the conversion from hydrophobicity to hydrophilicity and then to hydrophobicity.Meanwhile,the CO₂ bubbles generated in-situ were increase the contact area and consequently promoted the extraction of analytes.Unlike traditional LPME that performed in a centrifuge tube,this proposed method with simultaneous extraction and enrichment was completed in the syringe,and the phase separation can be realized without centrifugation.In order to improve the extraction efficiency,the type and volume of extractant,the type and volume of p H regulator and the extraction time were optimized.The optimum extraction conditions were as follows.Extraction solvent,nonanoic acid（200μL）;p H regulators,2mol L^-1 Na₂CO₃（400μL）and 2mol L^-1 H₂SO₄（300μL）;extraction time,1.5 min.Within the concentration range of 2-200 ng m L-1(NOR and CIP were2-100 ng m L^-1),a good linearity was acquired for all analytes（R~2 was between 0.9995 and0.9999）,the extraction recovery was 62.82%-116.95%,and the RSD of intra-day（n=3）and inter-day（n=6）precision was less than 6.21%.The limit of detection was 3 ng g^-1 and the limit of quantification was 10 ng g^-1.The extraction process of this method is completed in the syringe,and the phase separation can be realized without centrifugation.The results demonstrated that the developed approach is simple,accurate,effective and environmentally friendly.