Determination of 11 Trace Metel Elements in Edible Vegetable Oil by High-Resolution Inductively Coupled Plasma Mass Spectrometry after Ultrasonic Extraction with Hydrochloric Acid

A method for the rapid determination of trace metel elements including aluminum, barium, cadmium, copper, iron, magnesium, manganese, nickel, lead, vanadium, and zinc in edible vegetable oil by high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS) after ultrasonic extraction with hydrochloric acid was proposed. 2.0 g of edible vegetable oil sample was taken into a 50 mL-plastic centrifuge tube, and 800 μL of ICP solvent oil was added. After thoroughly mixing on a vortex mixer, 10 mL of 2.0 mol·L⁻¹ hydrochloric acid solution was added, and the mixture was sonicated at 70 ℃ for 30 min and cooled. The mixture was centrifuged at a rotational speed of 10 000 r·min⁻¹ for 5 min. After separating the aqueous phase from the organic phase, the aqueous phase was collected, in which 11 elements were determined by HR-ICP-MS, with medium resolution mode for isotopes to be tested of ⁵¹V, ⁵⁶Fe, ²⁷Al, ⁶³Cu, ²⁴Mg, ⁵⁵Mn, ⁶⁰Ni, and ⁶⁶Zn, and low resolution mode for ¹³⁷Ba, ¹¹¹Cd, and ²⁰⁸Pb. As shown by the results, linear relationships between the corresponding response intensity and mass concentrations of 11 elements were found within 100 μg·L⁻¹, with detection limits (3s) of 0.012—0.173 μg·L⁻¹. Test for recovery was made on edible vegetable oil sample by standard addition method, giving results in the range of 86.9％—107％. RSDs (n=7) of the determined results were in the range of 1.1％—4.9％. The method was applied to analysis of 3 edible vegetable oil samples, and the determined values of this method were basically consistent with those of the standard methods.