Abstract:

An ultrasonic extraction-reversed phased HPLC method was developed for the simultaneous separation and determination of 6 common preservatives such as benzoic acid, sorbic acid, methylparaben, ethyl P-hydroxybenzoate, nipasol and butyl P-hydroxybenzoate. Samples were extracted with the mixture of water and methanol (5:95, V/V) in ultrasonic field. The gradient elution was carried out on a Supelco Discovery C18 column, with an initial mobile phase of acetonitrile-acetate buffer (pH 4.4) and at the flow rate of 1.0 ml/min. The detector wavelength was set at 254 nm. Under these conditions, the separation of the 6 components was achieved within 14 min. The linear ranges for the determination 6 preservatives by this method were from 5 to 100 μg/ml with a correlation coefficient (r) of 0.9997－1.000, and the limits of detection were 0.012－0.43 μg/ml. The average recoveries for the 6 preservatives in sample spiked at three levels (10, 50 and 100 μg/g) were 90.1%－106.3% (n = 3). The RSDs of precision and stability were 0.58%－ 1.79% (n = 5) and 0.15%－ 1.65%, respectively. Finally, this method was applied to analysis of these preservatives in 30 different imported and exported food samples. Altogether, the pre-treatment procedure of the developed method is simple and rapid, and the result is sensitive and accurate.

Key words: RP-HPLC, ultrasonic extraction, simultaneous determination, preservative, foods