Analysis And Risk Assessment Of Cr,As,Pb In Edible Vegetable Oils

At present,the method for determining the content of heavy metals in edible vegetable oils is mainly the pretreatment of samples by wet digestion.The digestion method requires the use of a large amount of concentrated acid,which has a greater environmental pollution.At the same time,the sample processing time of the digestion method is long,and it is easy to cause bumps,increased reagent blanks,and the like during the operation process,and the operator's requirements are high.The dispersion-liquid microextraction method is an emerging sample pretreatment technology used in liquid sample pretreatment in recent years.This technology has been well analyzed and researched in water quality analysis because of its simple operation,rapidity,low reagent usage,and environmental friendliness.The thesis focuses on the principle of dispersion-liquid microextraction and its application in the detection of heavy metals in liquid samples.Combining the research status of dispersion-liquid microextraction,a method for the analysis of heavy metals in edible vegetable oils by liquid-liquid microextraction combined with graphite furnace atomic absorption spectrometry(GF-AAS)was established.The results were good.The specific research content and results are as follows:In this paper,Triton X-114 was used as dispersant,nitric acid and ethanol as extractants to extract and enrich chromium,arsenic,and lead in edible vegetable oils.The three kinds of chromium,arsenic,and lead were separated by graphite furnace atomic absorption spectrometry.Elements were measured and analyzed.This paper systematically studied the optimization conditions of graphite furnace atomic absorption spectrometry for the determination of chromium,arsenic,and lead.At the same time,the factors such as the type and concentration of dispersants,the type and concentration of the extractant,reaction equilibrium time,reaction temperature,and centrifugation time were investigated.Its effect on the extraction of chromium,arsenic and lead in edible vegetable oils by liquid-liquid microextraction.The results showed that the dispersant was Triton X-114(10%,v/v),the extractant was nitric acid(20%,v/v)and ethanol(0.2 mL),the shaking extraction time was 20 min,the extraction temperature was 40°C,The effect of the experimental extraction is best under the condition of 8 minutes of centrifugation.In this experiment,chromium,arsenic and lead in actual edible vegetable oil samples were compared and verified by the national standard method and the dispersion-liquid microextraction method.The extraction efficiency of the dispersion-liquid microextraction method reached chromium of 86.81%-99.35.%,arsenic were 86.61%-100.73%,and lead was 91.73%-98.16%.The results showed that the dispersion-liquid microextraction method can meet the determination of heavy metal content in edible vegetable oils.The method is simple,convenient,fast,and has good stability and good selectivity.This article analyzes the health risk of the health effects of chromium,arsenic and lead contained in the commercially available vegetable oil samples.The results show that the chromium,arsenic,and lead in commercial edible vegetable oils are three heavy metals.Content does not exceed the standard,while no significant impact on human health.