New fluorescent labeling reagent Benzimidazo[2,1- b ]quinazoline-12(6H) -one-5-ethylimidazole ester and its application in the analysis of endocrine disrupting compounds in milk by high performance liquid chromatography with fluorescence detection

Abstract A new fluorescent labeling reagent, benzimidazo[2,1- b ]quinazoline-12(6H)-one-5-ethylimidazole ester (BQEIC), was designed and synthesized, and successfully applied to the analysis of endocrine-disrupting compounds (EDCs) by high performance liquid chromatography (HPLC) with fluorescence detection. BQEIC reacted with EDCs under mild conditions with 4-dimethylaminopyridine as basic catalyst. The derivatives showed excellent fluorescence property with excitation and emission wavelength of 302 nm and 401 nm respectively. Under the optimal conditions, good linearity was observed in the concentration range of 20.0 to 200 μg L −1 with correlation coefficients of >0.996. The limits of detection and limits of quantification were in the range of 10.5–13.8 and 33.1–37.9 ng L −1 , respectively. The average recoveries ( n  = 3) were in the range of 92.6–98.5%. The developed method was successfully applied to analyze the EDCs residues in milk samples.