Abstract: This study aimed to establish the determination method of four paraben preservatives including methylparaben (MP), ethylparaben (EP), propylparaben (PP) and butylparaben (BP) in dairy products by high-performance liquid chromatography-mass spectrometry (HPLC-MS) with a column of C18 and a mobile phase consisting of methanol -water by gradient elution. The samples were solved by methanol and purified with SPE-C18. These preservatives were detected with diode array detector at 254 nm. Separation of the four components was achieved within 12 min. Under these conditions, the correlation coefficients are larger than 0.9994 for four parabens. The average recoveries are in the range from 97.4 % to 106.4%. Further affirmation was achieved using electrospray ionization (ESI) mass specturometry by negative mode. This method is quick, simple and accurate, and could be applied to determine parabens in dairy products.

Key words: parabens, preservative, HPLC-MS, dairy products, solid phase extraction