Abstract: Fast qualitative and semi-quantitative detection methods to distinguish hogwash oil in edible oil were developed by measuring conductivity. The effects of oil type, temperature, oscillation time, and oil/water ratio on conductivity were explored to establish optimal detection conditions. Through determining the conductivity of all kinds of hogwash oil and edible oil, a quantitative adulteration model of hogwash oil in edible oil was established and validated. The results indicated that the conductivities of crude hogwash oil, refined hogwash oil and edible oil in water phase were determined to be 30.15－130.80, 22.37－44.61μS/cm and 3.18－9.18μS/cm, respectively, under the conditions: room temperature, oscillation time of 30 s, oil/water ratio of 1:4 (g/mL) and phase separation time 10 min. When the conductivity of an edible oil sample was higher than 10μS/cm, the adulteration of this edible oil could be concluded and the semi-quantitative analysis can be completed by the established model.

Key words: hogwash oil, conductivity, qualitative and semi-quantitative analysis