A sensitive and accurate analytical method was developed and validated for the determination of di-(2-ethylhexyl)-phthalate(DEHP)metabolites in human serum by ultra performance liquid chromatographytandem mass spectrometry with solid phase extraction.The serum added with sodium acetate solution and internal standard(13C4MEHP)was hydrolyzed with beta-Glucuronidaseat at 37℃for 12 hours.The pretreated sample was condensed in the purified water after loading,washing and purifying through MAX solid phase extract...