AS NZS 1605.3:2018 pdf free.Methods for sampling and analysing timber preservatives and preservative- treated timber Part 3: Analysis methods for determination of preservative retention.
2.1 PRINCIPLE
Copper, chromium and arsenic compounds arc leached quantitatively from the timber sample with a mixture of diluted sulphuric acid and hydrogen peroxide solution. After adding sodium sulphate to the resulting extracts, the elemental concentrations are determined by atomic absorption spectrophotornetry.
NOTE: The method may be used for copper alone in determining the copper content in timber treated with copper-based preservatives.
2.2 REAGENTS
All reagents shall be of analytical reagent quality. The water used for preparing the reagents shall be distilled.
The following reagents shall be used:
(a) Sulphuric acid, 2.5 M Cautiously add, with stirring and cooling, 280 mL sulphuric acid (sg = 1 .84 g/mL) to 1500 rnL water. Cool and dilute with water to 2000 mL.
(b) Hydrogen peroxide solution, 30% (100 volume).
(c) Sodium sulphate, 3.0% solution Dissolve 30 g anhydrous sodium sulphate in water and dilute with water to 1000 mL.
(d) Sulphuric acid, 0.5 M/sodium sulphate 3.0% diluent solution Dilute 200 mL sulphuric acid solution [(Clause 2.2(a)] plus 100 mL of 3.0% sodium sulphate solution to 1000 mL with water and mix.
(e) Standard solution (1 iisL = 500 pg of arsenic)
The standard solution shall be prepared as follows:
(i) Dissolve 0.9825 g copper sulphate pentahydrate, CuSO45H2O, in a little water and transfer the solution to a 500 mL one-marked volumetric flask.
(ii) Dissolve 1.4135 g potassium dichrornate, K2Cr2O7, in a little water, add 50 rnL sulphuric acid solution [Clause 2.2(a)] and 10 mL hydrogen peroxide solution [Clause 2.2(b)]. Boil, cool and transfer the mixture to the one-marked volumetric flask containing the copper sulphate solution.
(iii) Dissolve 0.6600 g arsenic trioxide, As203, by boiling it in a solution containing 50 rnL sulphuric acid solution [Clause 2.2(a)] 10 mL hydrogen peroxide solution [Clause 2.2(b)] and 75 rnL water. Cool and transfer it to the one-marked volumetric flask. Add 50 mL sodium sulphate solution [Clause 2.2(c)] to the one-marked volumetric flask. Dilute to the mark with water and mix.
2.3 PROCEDURE
2.3.1 Instrument settings and operation
The instrument settings and operating conditions for determining copper, chromium and arsenic shall be as recommended in the instrument user’s manual.AS NZS 1605.3 pdf download.