Determination of nonionic surfactant biodegradability: Physical properties vs. colorimetry

Biodegradation studies with three alkyl phenol nonionic products have revealed that loss of cobaltothiocyanate colorimetric sensitivity may not necessarily correlate with loss of surface tension lowering and foaming properties when these type structures are exposed to microbial attack. Where this type of disagreement between analytical methods is present, only the surface tension and foam data are valid measurements of biodegradation.