Extraction methods finishing tests

An important QC analysis in the fibre and textile industry is the surface finish determination by Soxhlet extraction (AATCC Test Method 94-1992). Solvent extraction is used on textile materials to determine naturally occurring oily and waxy materials that have not been completely removed from the fibres (ASTM Method D 2257-96). Meanwhile, environmental, safety... 

Several studies have shown that certain categories of poorly or untreated petroleum base oils can cause cancer in humans. The principal molecular types believed to be responsible are the three- to seven-ring polycyclic aromatics. The IP 346 test method selectively extracts these materials from a sample of the base oil and enables their concentration to be estimated, fully described in a CONCAWE report [3]. Base oils are now classified according to this test method for their carcinogenic potential and the labelling of finished lubricant products must now comply with these rules. 

The method consists of taking cylindrical test coupons of specified dimensions and surface finish, and suspending them in a specified volume of a specified test solution representative of a moderately aggressive supply water for a period of 24 hours. The immersions are repeated ten times using fresh test solution. Metals are determined using the extract from the final 24-hom period. 

Water and oil repellent finishes, normally perfluoroalkyl sulfonate (PFAS) and perfluorooctane sulfonate (PFOS), are not to be used, and their threshold limit is 1 pg/m each in the coated material whereas all other PFAS forms, the threshold limit is 20 pg/kg and MSDS is required to be supplied for verification. The test method is based on solvent extraction and GC-MS or HPLC-MS. For per fluoro carboxylic acids and salts (PFCA), the limiting value is 0.05 ppm or sum total is 0.1 ppm. 

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