GB5009.34-2016

GB5009.34-2022 (New National Standard)

Inspection Method

Titration method

Titration method changed to: Acid-Base Titration, with the addition of Spectrophotometry Method, and the Third Method Ion Chromatography.

Scope of Inspection

This standard specifies the method for determining total sulfur dioxide in foods such as candied fruits, dried vegetables, rice noodles, vermicelli, sugar, edible mushrooms, and wine.

French Acid-Base Titration Method, suitable for the determination of sulfur dioxide in food.
The French method of spectrophotometry, the direct extraction method is suitable for the determination of sulfur dioxide in sugar and sugar products, starch and starch products, and ungreasy wet noodle products, where the extraction liquid is free of color interference; the nitrogen-purged distillation extraction method is suitable for the determination of sulfur dioxide in colored samples such as wine and raw sugar.
The third method is ion chromatography, suitable for the determination of sulfur dioxide in food.

Sample Preparation

5g uniform sample (up to 0.001g, sampling quantity varies with the content level); liquid samples can be directly aspirated 5.00mL to 10.00mL; add 250ml of water; add 10ml of hydrochloric acid.

Collect solid or semi-liquid samples20g to 100g (to 0.01g, sample size depends on content level); take 20mL (g) to 200mL (g) of liquid sample; add 20-500ml of water; add 10ml of 6mol/L hydrochloric acid.

Is Nitrogen Filling Available for Distillation?

No

Nitrogen Filling and Distillation, Flow Rate:0.2-2.0L/min

Absorbent liquid

25mL Lead Acetate Absorption Solution

50mL 3% Hydrogen Peroxide Solution (French)

Distillation Method

Gather200ml distillate, re-distill for 1 minute, and rinse the insertion device into the absorbent liquid with a small amount of distilled water.

The solution inside the flask is heated to boiling and maintained at a gentle boil.1.5h。

Titration method

Add sequentially to the removed iodine bottle10mL hydrochloric acid, 1mL starch indicator solution; mix well and titrate with standard iodine solution until the solution turns blue and remains so for 30 seconds. Perform a blank test simultaneously.

Cool the absorbent solution and shake well before adding3 drops of 2.5 mg/mL methyl red ethanol solution indicator, titrated with a sodium hydroxide standard solution (0.01 mol/L) to a yellow color that does not fade within 20 seconds, while performing a blank test concurrently.

Detection Limit vs. Quantitation Limit

When picking upFor 5G solid samples, the method's limit of detection (LOD) is 3.0 mg/kg, and the limit of quantitation (LOQ) is 10.0 mg/kg; for 10 mL liquid samples, the LOD is 1.5 mg/L, and the LOQ is 5.0 mg/L.

When usingAt a 0.01mol/L sodium hydroxide titrant, for solid or semi-liquid samples weighing 35g, the detection limit is 1mg/kg and the quantification limit is 10mg/kg; for liquid samples of 50mL (g), the detection limit is 1mg/L (mg/kg) and the quantification limit is 6mg/L (mg/kg).

Product Recommended Model

FX-3L460 Model