GB 5009.90-2016National food safety standard - Determination of iron in foods (English PDF)

Foreword

This standard replaces methods for the determination of iron content in GB 5413.21-2010 "National food safety standard - Determination of calcium, iron, zinc, sodium, potassium, magnesium, copper and manganese in foods for infants and young child"; GB/T 23375-2009 "Determination of copper, iron, zinc, calcium, magnesium and phosphorus content in vegetables and derived products"; GB/T 5009.90-2003 "Determination of iron, magnesium and manganese in foods"; GB/T 14609-2008 "Inspection of grain and oils -Determination of copper, iron, manganese, zinc, calcium, magnesium in cereals and derived products by atomic absorption and flame spectrophotometry";

GB/T 18932.12-2002 "Method for the determination of potassium, sodium, calcium, magnesium, zinc, iron, copper, manganese, chromium, lead, cadmium contents in honey - Atomic absorption spectrometry"; GB/T 9695.3-2009 "Meat and meat products - Determination of iron content"; NY/T 1201-2006 "Determination of copper, iron and zinc content in vegetables and derived products".

As compared with GB/T 5009.90-2003, the main changes of this standard are as follows.

--- Standard name is changed to "National food safety standard -Determination of iron in foods";

--- Add microwave digestion, pressure tank digestion and dry digestion;

--- Add the inductively coupled plasma emission spectrometry;

--- Add the inductively coupled plasma mass spectrometry;

--- Delete spectrophotometry.

National Food Safety Standard -Determination of iron in foods

1 Scope

This standard specifies the determination of iron content in foods by flame atomic absorption spectrometry, inductively coupled plasma emission spectrometry and inductively coupled plasma mass spectrometry.

This standard applies to the determination of iron content in foods.

Method I. Flame atomic absorption spectrometry

2 Principles

After digestion, the sample is atomized by atomic absorption and the absorbance value is measured at 248.3 nm. Within a certain concentration range, iron absorbance value is directly proportional to iron content; compares with the standard series for quantitation.

3 Reagents and materials

Unless otherwise indicated, the reagents used in this method are guaranteed reagent, the water is the grade-2 water specified in GB/T 6682.

4 Instrument and equipment

Note. All glassware and Teflon digestion inner-tank must be soaked in nitric acid solution (1+5) overnight, washed repeatedly with tap water, finally rinsed with water.

5 Analytical procedures

6 Analysis results expression

The iron content in the sample is calculated in accordance with the equation (1).

7 Precision

The absolute difference between the two independent determinations obtained under repeatability conditions shall not exceed 10% of the arithmetic mean.

8 Others

When the sampling weight is 0.5 g (or 0.5 mL) and the constant-volume is 25 mL, the method detection limit is 0.75 mg/kg (or 0.75 mg/L) and the quantitative limit is 2.5 mg/kg (or 2.5 mg/L).

Appendix A

Microwave digestion temperature-rise program Microwave digestion temperature-rise program is as shown in Table A.1.

Appendix B

Reference conditions of flame atomic absorption spectrometry Reference conditions of flame atomic absorption spectrometry are as shown in

Table B.1.