Determination of phosphorus in edible oils by inductively coupled plasma—Atomic emission spectrometry and oil‐in‐water emulsion of sample introduction

The determination of phosphous was carried out using emulsion sample preparation followed by analysis by inductively coupled plasma‐atomic emission spectrometry. The optimal oil‐in‐water (o/w) emulsion and surfactant concentrations were found by applying response surface methodology. Two phosphorus emission lines were tested. Ethoxynonylphenol was a good choice for the emulsion preparation. The optimal concentration for the oil in the o/w emulsion and the surfactant concentrations were ca. 8.0–37% w/w and ca. 1.0–10% w/w ethoxynonylphenol, respectively, for the 213.620 nm line; and an oil phase emulsion concentration between ca. 18–32% w/w and ca. 3–8% w/w ethoxynonylphenol for the 214.911 nm emission line. Good agreement was found between calibration curves for emulsified aqueous standards solutions and o/w emulsions. The use of aqueous standards for calibration purposes is a good addition in the analysis of this type of oil sample where certified standards are not available. Recoveries ranged from 98 to 105% and from 102 to 116% for the 213 and 214 nm lines, respectively with relative standard deviations lower than 7%.