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 1 The 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 2 The 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.