GB/T 30797-2014The test method for safety of food detergents - Determination of arsenic contents (English PDF)

3.1 Principle

After the pre-treated sample, the sample solution Arsenic under highly acidic conditions are thiourea - ascorbic acid reduction to trivalent arsenic, then borohydride

Nascent hydrogen generated by the action of acid and potassium reduced to arsine arsine is introduced into the heated carrier gas "T" type quartz tube atomizer, arsenic is original

Son of arsenic hollow cathode lamp emission characteristic lines. In a certain concentration range, the absorbance of the sample is proportional to the arsenic content. Compared with the standard series

Compared quantitatively. If we take 1g sample, the method of detection was 0.075µg/g, the minimum detectable concentration was 0.25µg/g.

3.2 Reagents

Unless otherwise indicated in the analysis using only recognized as analytical reagents and GB/T 6682 provisions tertiary water.

3.2.1

hydrochloric acid, pure class distinctions.

3.2.2

hydrochloric acid, 110 (volume ratio) solution.

3.2.3

nitrate, pure class distinctions.

3.2.4

sulfuric acid, pure class distinctions.

3.2.5

sulfate, 115 (volume ratio) solution.

3.2.6

Sodium hydroxide, 5g/L solution Weigh 0.5g of sodium hydroxide dissolved in 100mL of water.

3.2.7

hydroxide, 200g/L solution, weighed 200g sodium hydroxide were dissolved in 1L of water.

3.2.8

borohydride, potassium, 15g/L solution Weigh 1.5g of potassium borohydride were dissolved in 100mL of sodium hydroxide solution (3.2.6), filtered, and storage

Stored in a plastic bottle, can be stored in the refrigerator for 1 week.

3.2.9

hydrogen peroxide, the mass fraction w (H2O2) = 30%.

3.2.10

thiourea - ascorbic acid solution, weighed 12.5g of thiourea [(NH2) 2CS], add 70mL water, dissolved by adding 2.5g ascorbic

Acid, diluted to 100mL, stored in a brown bottle and can be stored in the refrigerator for 1 month.