Method for rapidly determining whether quinizarin dye is doped in diesel oil

A method for rapidly determining whether the quinizarin dye is doped in the diesel oil, comprises: adding a certain amount of chilli oil sample in which the black coloring agent is doped into a colorimetric tube, adding 50 g/l NaOH solution accounting for 10% of the chilli oil sample volume and n-butanol accounting for 10% of the chilli oil sample volume, adding quinizarin solubilizer accounting for 7-15% of the chilli oil sample volume, performing the ultrasonic treatment for 2 to 5 min and layering, determining the quinizarin is contained and the sample is chilli oil if the indigo water layer exists, wherein the quinizarin solubilizer is 0.05 to 0.15 g/mL Na2S2O3 saturated Na2S solution. The invention has the advantages of few consumption, short time and high efficiency. The method can rapidly determine whether the quinizarin dye is doped in the diesel oil, and the result is reliable.