Comparison and research of the contents of mineral elements in commercial edible vegetable oils

The contents of Mg, K, Na, Ca, Fe, Cu, Zn, Sr and Mn in edible vegetable oils were determined by flame atomic absorption spectrometry with microwave digestion technique for disposing samples.The detection limit for each element was 0.00280μg/mL for Mg, 0.0338μg/mL for K, 0.0523μg/mL for Na, 0.00945μg/mL for Ca, 0.00539μg/mL for Fe, 0.00148μg/mL for Cu, 0.00289μg/mL for Zn, 0.0845μg/mL for Sr and 0.00516μg/mL for Mn respectively, and the recovery ratios of the elements ranged from 96.6% to 103.9%.The sums of the element contents determined in the vegetable oils from open markets were 967.75μg/mL and 969.06μg/mL in bulk, 847.52μg/mL in the bottle much higher than those in soybean oil, peanut oil and sunflower seed oil from a big supermarket, among them the sum of the content in solvent leaching oil was lower than that of in filter pressed oils from supermarket.The similarities of total content of the metallic elements determined in the oils from open markets were big, and the similarities in the oils from supermarket were small among compared with the oil in bulk number one.The Na/K ratios in the oils from open markets were among 1.63 ~ 1.68, and that in the oils from supermarket was 0.82 in solvent leaching soybean oil and 1.11 ~ 1.56 in filter pressed oils.Our research will offer a reference for identifying resembles illegal cooking oil and selecting which edible vegetable oil according to physical conditions.