A kind of preparation method of i-131 standard milk powder sample

Abstract

The disclosure belongs to the field of food detection, and relates to a preparation method of a I-131 standard powdered milk sample. The method comprises the following steps: a, preparation of an I-131 solution: adding I-131 into a HNO3 solution; b, drying and equipartition of powdered milk: drying a required amount of powdered milk to a constant weight, and equally partitioning the powdered milkinto sample boxes; c, adding of the I-131 solution: uniformly adding the I-131 solution prepared in the step a into the powdered milk sample prepared in the step b; d, drying: drying the powdered milksample of the I-131 solution added in the step c; e, smashing: grinding the sample dried in the step d till hard solid particles disappear; f, mixing: adding the sample ground in the step e into a three-dimensional mixing machine for mixing; g, split charging: uniformly charging the sample mixed in the step f into the sample boxes uniformly; h, checking of the uniformity: sampling the sample in the step g, and checking the uniformity; and i, storage: storing the I-131 standard sample qualified in the step h at a dark place. The I-131 standard powdered milk prepared by the invention has the advantages of no volatilization and high stability.

Description

technical field [0001] The disclosure belongs to the field of food testing, in particular to a method for preparing an I-131 standard milk powder sample. Background technique [0002] The analysis and measurement of I-131 in milk powder has always been one of the main nuclides monitored by the national food radiation inspection agency. The preparation of milk powder I-131 standard samples is the main link in the determination of instrument stability, instrument I-131 efficiency scale, and analytical method recovery in the analysis of milk powder sample I-131, and is the main reference material for accurate analysis of milk powder I-131. Currently, due to the volatility of I-131, it is necessary to use AgNO in alkaline solution or in acidic and neutral solution 3 As a stabilizer, it can exist, but the alkalinity reacts with the protein in milk powder to form a colloidal solid, which cannot be prepared as a standard sample; at present, the use of AgNO in acidic solution 3 Pr...

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Problems solved by technology

There are two main disadvantages of this method: ①The milk powder needs to be degreased and pretreated, which destroys the physical properties of the milk powder, changes the density of the milk powder, and affects the accuracy of the instrument’s efficiency scale; ②adds the AgNO after adding the milk powder 3 solution, due to the presence of powdered milk, in which I-131 cannot be completely combined with AgNO 3 Reacted and unstable, causing some I-131 in the milk powder to still be volatile, and the prepared standard sample had poor stability; ③The process is more complicated

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