Multiresidue Screening Method For Veterinary Drugs In Aquaculture Water By LC-Q-TOF

This paper establishes a multiresidue screening method for 7 kinds of 45 veterinary drugs in aquaculture water by LC-Q-TOF. The method applies to fish, shrimp and shellfish aquaculture water for multiresidues detection. The 7 kinds of 45 veterinary drugs include Sulfas, Triphenylmethanes, Fluorquinolones, Macrolides, Lincosamides, Estrogens and Chloramphenicols. Details are as follows:The first part establishes the LC-Q-TOF screening method for veterinary drug standards. With the optimal analysis conditions,7 kinds of 45 veterinary drugs are separated by Agilent Extend C18 chromatographic column(3.5μm,3.5x100mm) and detected by ESI+and ESI-mode respectively. The mobile phase for ESI+ mode is 5mmol/L ammonium acetate containing 0.1% formic acid aqueous solution and acetonitrile, and for ESI-mode is 5mmol/L ammonium acetate solution and acetonitrile. With the optimum mass spectrometry detective conditions,7 kinds of 45 veterinary drugs are verified for Retention Time and Accurate Mass by MS Scan mode, and for special product ions and optimal collision energy by Target MS/MS Scan mode. Every target compound should be verified with the precursor ion and at least two product ions. As the isomerides, there should be at least one different product ion. The results show that the mass error for 7 kinds of 45 veterinary drugs are below 5ppm, the calibration curves have good relationship in range of 1-500μg/L, the linear correlation coefficients are greater than 0.99 and the retention time deviations are less than 0.2%. The instrument detection limit LODs are 0.5-20μg/L, quantification limit LOQs are 1-50μg/L. The entire analysis process completes in 40 min, and the sensitivity, the degree of separation and repeatability satisfy the requirement of multi-veterinary residues detection, which could provide a powerful technical support.The second part establishes the mass spectrum database for 7 kinds of 45 veterinary drugs and optimize the screening parameters. The spectral library database contains the following information: the whole name, brief name, CAS number, formula, ionization mode, retention time, accurate molecular mass, mass spectrum per each collision energy and so on. By optimized the screening parameters of MS scan and MS/MS scan, the method is further confirmed the feasibility with low concentration standard for reference. The database lays a good foundation for fast screening veterinary multiresidue and provides the technical support for unknown sample screening.The third part establishes the pretreatment method and detective method at the same time for 7 kinds of 45 veterinary drugs in aquaculture water of fish, shrimp and shellfish. The sample is extracted and purified by Agela BAP solid phase column first, which is activated by methanol and ultrapure water previously. Being eluted by methanol,1% formic acid in acetonitrile and 10% methanol in ethyl acetate successively and collected all, the solution is dried by a stream of nitrogen and added purity water-acetonitrile (V/V,9:1) to be ready for injection. The targets are separated by Agilent Extend C18 chromatographic column and detected by ESI+ and ESI- mode respectively. The mobile phase for ESI+ mode is 5mmol/L ammonium acetate containing 0.1% formic acid aqueous solution and acetonitrile, and for ESI-mode is 5mmol/L ammonium acetate solution and acetonitrile. The results show that the 7 kinds of 45 veterinary drugs have good relationship in range of 1-500μg/L, the linear correlation coefficients are greater than 0.99, the method limits of detection are lower than 0.25μg/L Despite sulfaguanidine’s recovery is 58.85%, all rest recoveries are 70.22%-120.69%, the relative standard deviations(RSD) are 1.18%-22.03%. This method has high sensitivity and good accuracy, which can be used to screen the veterinary multiresidue. The results are both negative samples when apply this method to fresh (carp, northern and southern white shrimp, loach) and ocean (Abalone) aquaculture water samples.