Adsorption of systemic fungicides and a herbicide by some components of plant tissues, in relation to some physicochemical properties of the pesticides

Abstract Lignin, an important component of plant tissues, adsorbed five systemic fungicides and one herbicide (carbendazim, triadimefon, nuarimol, triarimol, fenarimol and fluometuron) more strongly than bovine serum albumin, cellulose, ethylcellulose or sodium polygalacturonate. Significant correlations were found between the extent of the adsorption of the pesticides on the lignins extracted from three different plant species, and the log Poet (Poet is the octan‐1‐ol/water partition coefficient) of the compounds. The more lipophilic fungicides triarimol and fenarimol (log Poet about 2.6) were adsorbed to the greatest extent. Fluometuron, triadimefon and nuarimol (log Poet about 2.0) were moderately adsorbed, whereas carbendazim with the lowest log Poet (1.34 at pH 5.0), was adsorbed more than expected from its Poet value. The anomaly of carbendazim is discussed; it is ascribed to it's partial protonation at pH 5.0, whereas the other pesticides were non‐ionised.