Gives methods to determine the monomer terephthalic acid in food simulants; distilled water, 3 % w/v acetic acid aqueous solution, 15 % v/v ethanol aqueous solution and olive oil or its approved substitutes, sunflower oil or a mixture of synthetic triglycerides. These methods are capable of determining terephthalic acid in the food simulants at the level of the specific migration limit in Commission Directive 90/128/EEC. .