GB 5009.182-2017National food safety standard - Determination of aluminum in foods (English PDF)

3.1 Reagents

3.1.1 Nitric acid (HNO3). guaranteed reagent.

3.1.2 Sulfuric acid (H2SO4). guaranteed reagent.

3.1.3 Hydrochloric acid (HCl). guaranteed reagent.

3.1.11 Ascorbic acid (C6H8O6).

3.2 Reagent preparation

3.2.1 Hydrochloric acid solution (1+1). MEASURE 50 mL of hydrochloric acid;

MIX it uniformly with 50 mL of water.

3.2.2 Sulfuric acid solution (1%). PIPETTE 1 mL of sulfuric acid; POUR slowly

into 80 mL of water; USE water to dilute it to 100 ml after cooling; MIX it

uniformly.

3.2.12 Ethylenediamine solution (1+2). MEASURE 10 mL of ethylenediamine;

slowly POUR into 20 mL of water; MIX it uniformly.

3.2.13 Ethylenediamine-hydrochloric acid buffer solution (pH6.7~7.0).

MEASURE 100 mL of ethylenediamine; slowly POUR into 200 mL of water

along glass rod; after cooling, ADD slowly 190 mL of hydrochloric acid along

glass rod; MIX it uniformly; if pH > 7.0 or pH < 6.7, USE hydrochloric acid

solution (1+1) or ethylenediamine solution (1+ 2) to adjust pH respectively.

3.2.14 Ascorbic acid solution (10 g/L). WEIGH 1 g of ascorbic acid; USE water

to dilute it to 100 mL; MIX uniformly. Prepare it before use.

3.3 Standards

Aluminum standard solution. 1000 mg/L. Or aluminum standard solution with a

certain concentration which is identified by national authentication and awarded

a reference material certificate.

3.4 Standard solution preparation

3.4.1 Aluminum standard intermediate solution (100 mg/L). Accurately

PIPETTE 1.00 mL of aluminum standard solution (1000 mg/L) into 10 mL

volumetric flask; ADD nitric acid solution (5%) to dilute it to the mark; MIX it

uniformly.

4.1 Spectrophotometer.

4.2 Balance. sensitivity is 1 mg.

4.5 Constant-temperature oven.

5.1 Sample Preparation

In the process of sampling and sample preparation, pay attention not to

contaminate the sample; avoid using aluminum-containing appliances.

5.2 Sample digestion

WEIGH 0.2 g ~ 3 g of sample (accurate to 0.001g) or accurately MOVE 0.500

mL ~ 5.00 mL of liquid sample into hard glass digestion tube or conical flask;

ADD 10 mL of nitric acid and 0.5 mL of sulfuric acid; HEAT it on adjustable

temperature-control electric furnace or hot plate, reference conditions.

5.3 Color reaction and colorimetric determination

Respectively PIPETTE 1.00 mL (V2) of sample digestive juice and blank

solution; PLACE them into 25 mL plugged colorimetric tube; ADD water to 10

mL. In addition, TAKE seven 25 mL plugged colorimetric tubes; ADD

respectively aluminum standard working solution 0 mL, 0.500 mL, 1.00 mL,

2.00 mL, 3.00 mL, 4.00 mL and 5.00 mL (in the series standard solution, the

mass of aluminum is 0 µg, 0.500 µg, 1.00 µg, 2.00 µg, 3.00 µg, 4.00 µg, 5.00

µg respectively); ADD 1 mL of sulfuric acid solution (1%) in each tube

successively; ADD water to 10 mL.

10.1 Reagents

mL of water; MIX it uniformly.

10.2.2 Nitric acid solution (5+95). MEASURE 5 mL of nitric acid; POUR into 95

mL of water; MIX it uniformly.

10.3 Standards

Aluminum standard solution. 1000 mg/L. Or aluminum standard solution with a

certain concentration which is identified by national authentication and awarded

a reference material certificate.

10.4 Standard solution preparation

10.4.1 Aluminum standard intermediate solution (100 mg/L). Accurately

PIPETTE 1.00 mL of aluminum standard solution (1000 mg/L) into 10 mL

volumetric flask; ADD nitric acid solution (5+95) to dilute it to the mark; MIX it

uniformly.

11.1 Graphite Furnace Atomic Absorption Spectrometer. Attached aluminum

11.4 Adjustable hot plate.

11.5 Microwave digestion instrument. equipped with Teflon digestion inner-tank.

11.6 Pressure digestion pot. equipped with Teflon digestion inner-tank.

11.7 Constant-temperature oven

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