What method is used to determine copper content in the treated timber?

The standard specifies an iodometric titration method where liberated iodine is titrated against standard sodium thiosulphate.

How is Pentachlorophenol (PCP) quantified?

PCP is extracted using suitable organic solvents and quantified using a spectrophotometric method by comparing sample absorbance against a standard calibration curve.

Why test for these specific preservatives?

Copper organics and PCP are heavy-duty preservatives used to prevent fungal decay and termite attacks; testing ensures the timber has absorbed the minimum protective threshold.

IS 2753

: 2000

Methods for estimation of preservatives in treated timber and in treating solutions, Part 2: Determination of copper (in copper organic preservative salt) and pentachlorophenol

CurrentSpecializedTesting MethodMaterials Science · Timber and Timber Stores

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This standard specifies the chemical analysis methods for quantitatively estimating the concentration of copper (in copper organic preservatives) and pentachlorophenol (PCP) in both treated timber and treating solutions. It is crucial for ensuring that wood preservation treatments meet the required retention limits to protect against decay and insect attacks.

Methods for estimation of preservatives in treated timber and in treating solutions, Part 2: Determination of copper (in copper organic preservative salt) and pentachlorophenol

Quick Reference Values

Typical timber sample mass for extraction5 g

Normality of standard sodium thiosulphate solution0.1 N

Spectrophotometric absorption wavelength for PCP430 nm to 450 nm

Key Formulas

Copper, percent by mass = (V × N × 0.06354 × 100) / M (where V is volume of standard sodium thiosulphate, N is normality, M is mass of sample)

Practical Notes

Use a Soxhlet apparatus for thorough extraction of PCP from the timber sample.

Pentachlorophenol is highly toxic; extractions and sample preparations should be conducted in a fume hood with appropriate PPE.

Ensure that only analytical grade reagents and distilled water conforming to IS 1070 are used to avoid analytical errors in titration.