Determination of UV absorption at 232 nm, fatty acid composition, trilinolein and triglycerides of 42 equivalent carbon number in olive and olive residue oils: Statistical assessment of the precission characteristics from a collaborative trial

Abstract

Some analytical methods for the determination of olive oil characteristics included in the European Union and International Olive Oil Council regulations lack precision data. To overcome such inconvenient a collaborative trial was set up including 22 laboratories from governmental institutions and industries. UV absorption at 232 nm, fatty acid composition, trilinolein and triglycerides with 42 equivalent carbon number were the tried methods. Repeatability and reproducibility data were obtained using the statistical method included in the International Standard ISO 5275/1986 (E).The effect of oil purification through a silica gel column on K232 and triglycerides was also studied. Finally for fatty acid determination, methylations by cold methanolic potash and by heating with methylated sodium were compared.