GB/T 5413.23-1997National food safety standard -- Determination of iodine in foods for infants and young children, milk and milk products (English PDF)

Foreword

This standard replaces GB/T 5413.23-1997 "infant formula and milk powder Determination of Iodine" this standard compared with GB/T 5413.23-1997, main changes are as follows.

- To fill the column quartz capillary column;

- Increase the detection limit.

Appendix A of this standard is an informative annex.

This standard replaces the standards previously issued as follows.

--GB 5413-1985, GB/T 5413.23-1997.

National Food Safety Standard Determination of infant foods and dairy iodine

1 Scope

This standard specifies the method for determination of infant foods and dairy iodine.

This standard applies to the determination of infant foods and dairy iodine.

2 Normative references

The standard file referenced in the application of this standard is essential. For dated references, only the edition date of the note Apply to this standard. For undated references, the latest edition (including any amendments) applies to this standard.

Principle 3

Iodine in the sample under conditions of sulfuric acid and iodine derivatives generate butanone and butanone reacted by gas chromatography with electron capture detector inspection Testing, external standard.

4 Reagents and materials

Unless otherwise specified, the reagents used in this method are analytically pure water GB/T 6682 provided a water.

4.1 Peak's (Taka-Diastase) amylase. enzyme activity >=1.5 U/mg.

4.2 potassium iodide (KI) or potassium iodate (KIO3). pure class distinctions.

4.3 butanone (C4H8O). chromatography.

4.4 sulfuric acid (H2SO4). pure class distinctions.

4.5 n-hexane (C6H14).

4.6 anhydrous sodium sulfate (Na2SO4).

4.7 Hydrogen peroxide (3.5%). lessons 11.7 mL volume fraction of 30% hydrogen peroxide diluted to 100 mL.

4.8 potassium ferrocyanide solution (109 g/L). Weigh 109 g of potassium ferrocyanide, water volume to 1000 mL volumetric flask.

4.9 zinc acetate solution (219 g/L). Weigh 219 g of zinc acetate, water volume to 1000 mL volumetric flask.

4.10 iodine standard solution.

4.10.1 iodine standard stock solution (1.0 mg/mL). Weigh 131 mg of potassium iodide (4.2) (accurate to 0.1 mg) or 168.5 mg potassium iodate (4.2) (accurate to 0.1 mg), dissolved in water and dilute to 100 mL, 5 °C ± 1 °C refrigerated within a week effective.

4.10.2 iodine standard working solution (1.0 µg/mL). draw 10 mL standard stock solution of iodine, water volume to 100 mL and mix, then draw 1.0 mL, 100 mL water to the mix, prepared before use.

5 Apparatus

5.1 Balance. a sense of the amount of 0.1 mg.

5.2 Gas chromatography with electron capture detector.

6 Step, Analysis

7 Expression analysis

The iodine content of the sample according to equation (1).

100 × =

CX s (1)

Where.

X-- sample iodine content in micrograms per hundred grams (µg/100 g);

Cs-- iodine content in the sample obtained from the standard curve, in micrograms (µg);

m-- sample mass, in grams (g).

The arithmetic mean of two under the same condition of independent determination results indicated that the results of reservations to one decimal place.

8 Precision

Two independent determination results under the absolute difference in repetition condition must not exceed 10% of the arithmetic mean.

9 Other

The standard detection limit of 2.0 µg/100 g.

Appendix A

(Informative)

Iodine standard derivative gas chromatogram A.1 iodine standard derivative gas chromatogram Iodine standard derivative gas chromatography is shown in Figure A.1.

Figure A.1 iodine standard derivative gas chromatogram