Determination of total iodine in French Polynesian foods: Method validation and occurrence data

Pacific Island populations show some of the highest incidences of thyroid cancer in the world, and iodine deficiency is suspected to play a role. Iodine content was determined in 124 different French Polynesian food samples using inductively coupled plasma-mass spectrometry after alkaline digestion. For samples containing starch, the method was optimised by including an additional enzymatic treatment step. This analytical method was validated with an accuracy profile approach, using certified reference materials with iodine contents ranging from 0.027 to 4.95 mg iodine kg^-1 dry weight. The trueness bias ranged from -5.8% to 22.4% and the highest observed intermediate precision coefficient of variation CV_R was 11% in starchy materials. Tested Polynesian foods showed large variation in iodine content, with values of 0.014-0.032 mg kg^-1 for fruits, 0.014-0.081 mg kg^-1 for starchy samples, 0.027-1.85 mg kg^-1 for green vegetables, 0.222-5.19 mg kg^-1 for fish, 6.51-85.6 mg kg^-1 for shellfish, and 0.004-1.39 mg kg^-1 for beverages.