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GB/T 5009.90-2003 PDF in English

GB/T 5009.90-2003 (GB/T5009.90-2003, GBT 5009.90-2003, GBT5009.90-2003)
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GB/T 5009.90-2003: PDF in English (GBT 5009.90-2003)

GB/T 5009.90-2003
ICS 67.040
C 53
Replacing GB/T 12396-1990
Determination of iron, magnesium and manganese in foods
Issued by. Ministry of Health of the People's Republic of China;
Standardization Administration of the People's Republic of
Table of Contents
Foreword ... 3 
1  Scope ... 4 
2  Principle ... 4 
3  Reagents ... 4 
4  Instruments ... 5 
5  Analysis procedures ... 5 
6  Precision ... 7 
This Standard replaces GB/T 12396-1990.
Compared with GB/T 12396-1990, main changes of this Standard are as follows.
— Changed the Chinese title to be Determination of iron, magnesium and manganese
in foods;
— Changed the structure of previous standard according to GB/T 20001.4-2001 Rules
for drafting standards - Part 4. Methods of chemical analysis.
This Standard was proposed by and shall be under the jurisdiction of the Ministry of Health
(MOH) of the People's Republic of China.
Chief draft organization of this Standard. Nutrition and Food Hygiene Research Institute of
Chinese Institute of Preventive Medicine.
Chief drafters of this Standard. Zhou Xinghan, Men Jianhua and Wang Guangya.
This Standard was issued for the first-time in 1990; this is the first revision.
Determination of iron, magnesium and manganese in foods
1 Scope
This Standard specifies the determination of iron, magnesium and manganese in foods
through atomic absorption spectrophotometric method.
This Standard is applicable to the determination of the iron, magnesium and manganese
in various foods.
The detection limit of this method. 0.2μg/mL for iron, 0.05μg/mL for magnesium, and
0.1μg/mL for manganese.
2 Principle
After the test sample is wet-digested, IMPORT it into the atomic absorption
spectrophotometer; after flame atomization, the iron, magnesium and manganese
respectively ABSORB the 248.3nm, 285.2nm and 279.5nm resonance lines; the
absorbing capacities are proportional to their contents; compare and quantify with the
standard series.
3 Reagents
3.1 Hydrochloric acid.
3.2 Nitric acid.
3.3 Perchloric acid.
3.4 Digestive fluid of mixed acid. nitric acid + perchloric acid = 4+1.
3.5 0.5mol/L nitric acid solution. measure 32mL of nitric acid, then add deionizer water
and dilute it to 1000mL.
3.6 Standard solutions
Iron, magnesium and manganese standard solutions. Accurately weigh 1.0000 g of metal
iron, metal magnesium and metal manganese respectively (purity is larger than 99.99%),
or corresponding oxide that contains 1.0000 g of pure metal. Respectively add nitric acid
to dissolve; transfer them to three 1,000mL volumetric flasks; add 0.5 mol/L nitric acid
solution and dilute to the graduation. Store it in polyethylene bottles at 4°C. Each milliliter
of the three solutions is equivalent to 1 mg of iron, magnesium and manganese
Other experimental conditions. The instrument slit, air and acetylene flow, lamp holder
height and element lamp current etc. shall be adjusted to the optimal state according to
the apparatuses’ instructions.
5.3 Result calculation
Draw standard curve according to standard solution of various concentrations and
corresponding absorbance.
For determination sample solution and reagent blank solution, the concentrations (c and
c0) are found out through the standard curve, then CALCULATE according to Formula (1).
X - element content in the sample, milligrams per hectogram (mg/100g);
c - concentration of elements in sample solution for determination (found out through
the standard curve), microgram per milliliter (μg/mL);
c0 - concentration of elements in reagent blank solution (found out through the standard
curve), microgram per milliliter (μg/mL);
V - constant volume of the sample, milliliter (mL);
f - dilution ratio;
m - mass of sample, gram (g).
The calculation result reserves two significant digits.
6 Precision
The absolute difference of two independent determination results, under repeatability
conditions, shall not be over 10% of the arithmetic mean.
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.