Rapid Determination of Ethoxyquin Residues in Fruits by High Performance Liquid Chromatography with Fluorescence Detector
To establish a method for the determination of residual ethoxyquin in apple and pear samples by high performance liquid chromatograph tandem fluorescence detector.The fruit samples were mixed with ascorbic acid and homogenized for sample preparation.0.1 mol·L-1 sodium hydroxide solution was added to the samples.The samples were extracted by n-hexane for three times under alkaline conditions,and the liquid nitrogen was extracted and blown to dry.Dissolve with acetonitrile containing ascorbic acid,use liquid chromatography fluorescence detector method for machine measurement,and use external standard method for quantification.The excitation wavelength of fluorescence detector is 365 nm,the emission wavelength is 435 nm,and the mobile phase is acetonitrile : water = 65 : 35.The results showed that the method presented a good linear relationship in the concentration range of 2.00～200.00 ng·mL-1,the linear equation was Y=1.06×104X-1.74×103,and the correlation coefficient(r)was 0.999 97.Three concentration levels of 0.02 mg·kg-1,0.20 mg·kg-1 and 1.00 mg·kg-1 were added,and six parallel experiments were carried out.The recoveries were 81.09％～86.43％,and the relative standard deviations(RSD)were 1.18％～3.09％.The method is simple and rapid,has high extraction efficiency,high instrument sensitivity,good accuracy and repeatability,and can be used for the determination of ethoxyquin residues in fruits.
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