GB/T 24992-2010Paper,board and pulps - Determination of arsenic (English PDF)

3.1 Principle

After a wet sample digestion, remove nitric acid and other oxidizing acid, under acidic conditions, ascorbic acid solution was added thiourea make the digestion solution Five

Trivalent arsenic is reduced to trivalent arsenic and nascent hydrogen by the reaction of potassium borohydride and an acid solution produced by the reaction and generate gaseous hydrides, brought by the carrier gas

Quartz atomizer thermal decomposition into atomic arsenic in arsenic hollow cathode lamp emits a light beam emitted from excited, to produce atomic fluorescence, fluorescence

Intensity proportional to the amount of arsenic, compared with standard series quantified.

3.2 Reagents

Unless otherwise indicated, used in the analysis confirmed only for the gifted class pure reagents.

3.2.1

Water, GB/T 6682, Grade 2.

3.2.2

nitric acid (HNO3), rho = 1.40g/mL, the mass fraction is 65% to 68%.

3.2.3

hydrochloric acid (HCl), rho = 1.18g/mL, the mass fraction is 36% to 38%.

3.2.4

sulfuric acid (H2SO4), rho = 1.84g/mL, mass fraction of about 95% to 98%.

3.2.5

hydrochloric acid (HCl), 5 95, the 50mL of hydrochloric acid (3.2.3) is added to a volume of 950mL water.

3.2.6

solution of potassium hydroxide (KOH), 20%, weighed 20g of potassium hydroxide dissolved in water volume in 100mL flask.

3.2.7

solution of potassium borohydride (KBH4), 2%, weighed 0.5g potassium hydroxide in a beaker with 100mL water dissolved, 2.0g of boron

Potassium hydride dissolved therein, if precipitate be filtered after use, and this solution using now.

3.2.8

thiourea ascorbic acid solution, 5 percent 5 percent, weighed 5.0g thiourea and 5.0g of ascorbic acid dissolved in 100mL water, this solution

Was using now.

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