title: Simultaneous determination of four synthesized metabolites of mequindox in urine samples using ultrasound-assisted dispersive liquid-liquid microextraction combined with high-performance liquid chromatography.
abstract: A novel pretreatment method termed ultrasound-assisted dispersive liquid-liquid microextraction (UADLLME) coupled with high-performance liquid chromatography-ultraviolet detector (HPLC-UV) was applied for the detection of four synthesized metabolites of mequindox in pig urine samples. A total volume of 200 μL of methanol (dispersant) and 60 μL of 1,1,2,2-tetrachloroethane (extract) were injected into 5.0 mL of urine sample and then emulsified by ultrasound treatment for 4 min to form a cloudy solution. The effect of several factors on the recovery of each metabolite was investigated by a fitting derivation method for the first time. Under optimum conditions, the method yields a linear calibration curve in the concentration range from 0.5 to 500 μg/L and a limit of detection (LOD) of 0.16-0.28 μg/L for target analytes. The recoveries ranged from 72.0% to 91.3% with a relative standard deviation (RSD) of less than 5.2%. The enrichment factors for the four compounds ranged from 75 to 95. Two pig urine samples were successfully analyzed using the proposed method.
authors.affiliation: Department of Applied Chemistry, China Agricultural University, Yuanmingyuan West Road 2#, Haidian District, Beijing 100194, China.
authors.forename: Jiaheng
authors.initials: J
authors.lastname: Zhang
authors.forename: Haixiang
authors.initials: H
authors.lastname: Gao
authors.forename: Bing
authors.initials: B
authors.lastname: Peng
authors.forename: Yubo
authors.initials: Y
authors.lastname: Li
authors.forename: Songqing
authors.initials: S
authors.lastname: Li
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Zhou
mesh_terms: D000818:Animals; D002138:Calibration; D002851:Chromatography, High Pressure Liquid; D004655:Emulsions; D004980:Ethane / Q000031:analogs & derivatives / Q000737:chemistry; D006843:Hydrocarbons, Chlorinated / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D057230:Limit of Detection; D059627:Liquid Phase Microextraction; D000432:Methanol / Q000737:chemistry; D010084:Oxidation-Reduction; D011810:Quinoxalines / Q000138:chemical synthesis* / Q000652:urine*; D015203:Reproducibility of Results; D012997:Solvents; D013010:Sonication; D013552:Swine
chemical_list: D004655:Emulsions; D006843:Hydrocarbons, Chlorinated; C545385:Mequindox; D011810:Quinoxalines; D012997:Solvents; C015530:1,1,2,2-tetrachloroethane; D004980:Ethane; D000432:Methanol