This document, part of EN 13130, specifies an analytical procedure for the determination of 3,3-bis(3-methyl-4-hydroxyphenyl)-2-indolinone in the food simulants water, 3 % w/v aqueous acetic acid, 15 % v/v aqueous ethanol and olive oil or approved substitute. The level of 3,3-bis(3-methyl-4-hydroxyphenyl)-2-indolinone determined, is expressed as milligrams of 3,3-bis(3-methyl-4-hydroxyphenyl)-2-indolinone per kilogram of food or food simulant. The method is applicable to the quantitative determination of 3,3-bis(3-methyl-4-hydroxyphenyl)-2-indolinone in an approximate analyte concentration range of 0,18 mg/kg to 4/ kg of food simulants.NOTE 1The method should also be applicable to other aqueous food simulants as well as to the other fatty food simulants e.g. a mixture of synthetic triglycerides or sunflower oil.NOTE 2The suitability of the fat simulant should be assessed prior to setting up migration tests. Olive oil has been found to give unacceptable interference in some cases.