A comparison of three activation analysis methods for iodine determination in foodstuffs

Abstract

Activation analysis methods based on the nuclear reactions ¹²⁷ I(n,γ ) ¹²⁸ I, ¹²⁷ I(n,2n)¹²⁶I and ¹²⁷ I(γ ,n)¹²⁶ I were tested in terms ofdetection limits, accuracy and precision, and applicability for iodine determinationat various levels in foodstuffs. Both nondestructive and radiochemical modeswere employed using one of the two separation procedures developed (alkaline-oxidativefusion and iodine separation either by extraction of elemental iodine in chloroformor AgI precipitation). The lowest iodine detection limit of 1 ng . g ^—1 was achieved by employing the first nuclear reaction followedby separation of elemental iodine. Accuracy and precision of the proceduresdeveloped at largely different iodine levels were proved by analyses of biologicalreference materials having composition similar to that of various food items.