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Environmental fate & pathways

Adsorption / desorption

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Description of key information

The organic carbon-normalized soil adsorption coefficient (Koc) for components of PARAFORMALDEHYDE, OLIGOMERIC REACTION PRODUCTS WITH 4-TERTBUTYLPHENOL, M-PHENYLENEBIS(METHYLAMINE) was estimated using OECD Guideline 121: “Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC)”. 

Key value for chemical safety assessment

Koc at 20 °C:
5 012

Additional information

The organic carbon-normalized soil adsorption coefficient (Koc) for components of PARAFORMALDEHYDE, OLIGOMERIC REACTION PRODUCTS WITH 4-TERTBUTYLPHENOL, M-PHENYLENEBIS(METHYLAMINE) was estimated using OECD Guideline 121: “Estimation of the Adsorption Coefficient (Koc) on Soil and on Sewage Sludge using High Performance Liquid Chromatography (HPLC)”. This method compares the retention time of the test material in a defined HPLC assay to the retention times of a series of reference substances with known Koc values. The reference substances utilized for this study included acetanilide, methyl benzoate, naphthalene, 1,2,3-trichlorobenzene, phenanthrene and DDT.

A linear regression line for reference substances was determined using the log k’ data plotted against the known log Koc values. The k’ value is the HPLC capacity factor that is derived from the retention time for a substance corrected for the dead volume in the

HPLC column. The Koc of the test material was then determined from its measured HPLC capacity factor using the equation for the fitted regression line.

Under buffered HPLC assay conditions, four chromatographic peaks were observed for the test material, having estimated log Koc values of 2.4, 3.9, 4.3 and 5.7. The test material components and their approximate concentrations associated with these four

peaks were tentatively identified using refractive index detection and retention time matching with 4-tert-butylphenol and MXDA standards. The total peak area observed for refractive index detection of the eluted test material components indicates that > 90% of

test material mass is accounted for in the eluted chromatographic peaks. The test material component having lowest estimated log Koc of 2.4 was 4-tert-butylphenol and the component having highest estimated log Koc of 5.7 was the reaction product of one mole paraformaldehyde with 1 mole of 4-tertbutylphenol and 1 mole MXDA. A weighted-average log Koc value of 3.7 was calculated for all of the eluted test material components. These estimated log Koc values from HPLC method are in good agreement with estimates derived from structure-property relationships based on molecular connectivity indices (U.S. EPA KOCWIN). The values of estimated log Koc from the HPLC and MCI estimation methods indicate that the test material and its components have moderate to strong affinity for adsorption to soil, sediment, and wastewater treatment biosolids.

[LogKoc: 3.7]