Determination of Phosphorus and Silicon in Edible Vegetable Oil by Inductively Coupled Plasma-Tandem Mass Spectrometry / 分析化学

ABSTRACT

An analytical method was developed for determination of P and Si in edible vegetable oil using inductively coupled plasma-tandem mass spectrometry (ICP-MS/MS).The microwave-assisted acid digestion of vegetable oil using HNO3 + H2O2 was carried out in closed vessels.The mass spectral interferences were eliminated by O2 mass shift when promoting reaction with O2 inside the collision reaction cell (CRC), and the monitoring of P as 31P16O+ product ion significantly improved the accuracy of the analysis.H2 was added into the CRC for H2 on-mass reaction.The interferences were eliminated by the quadrupole analyzer to accurately identify 28Si+.The effects of the flow rate of O2 and H2 in ORS3 on the signal intensities and BECs of 31P16O+ and 28Si+ were investigated.The optimum O2 and H2 flow rate was determined.Under the optimized conditions, the limits of detection were 0.043 and 0.66 μg/L for 31P16O+ and 28Si+, respectively.The accuracy of the analytical method was assessed by the analysis of the standard reference materials lubricant oil (SRM 1848) from the National Institute of Standard and Technology.No significant differences were observed between the certified values and measured values.This method was used to analyze 5 kinds of edible vegetable oils (rapeseed oil, sunflower oil, peanut oil, corn oil and soybean oil) from different regions of China, and it was found that the content of P was the highest in peanut oil, and Si showed the highest content in soybean oil.