The invention discloses a method for determining the lead content in
rapeseed oil. The method for determining the lead content in the
rapeseed oil comprises the following steps that 1, a 10-
phenanthroline solution, a
hydroxylammonium chloride solution and a 0.1%
thymol blue indicator are prepared; 2, a lead
standard solution is prepared; 3, the double-lead content is regarded as an x-coordinate and the
absorbance is regarded as a y-coordinate to make a lead
standard curve; 4, the
rapeseed oil is weighed, concentrated
hydrochloric acid, water and glass beads are added,
reflux boiling is performed, lower-layer acid extract liquid is filtered by double-layer
filter paper after standing and layering, filtrate is fed into a
beaker, a conical flask is cleaned, the liquid is poured into a funnel and then is mixed with the filtrate in the
beaker after layering, the
filter paper is flushed,
drying by
distillation is performed, and water is added for constant volume so as to obtain a liquid sample; 5, the liquid sample obtained in the step 4 is absorbed in a colorimetric tube, and a lead marking curve is made as the step 3. The method for determining the lead content in the rapeseed oil is quick, accurate, simple and convenient to operate, high in sensitivity and smaller in environment
pollution, does not use a highly toxic agent, has a minor
hazard to
human health and can meet the testing demands of ordinary experimenters.