Sentence:  In the over-all process , it is difficult to assign a `` pure '' role to each constituent of a built detergent formulation ; and , indeed , there is no more reason to separate the interrelated roles of the active , builder , antiredeposition agent , etc. than there is to assign individual actions to each of the numerous <WSD>isomers</WSD> making up a given commercial organic active . 
Meaning of the word marked with <WSD> tags:  a compound that exists in forms having different arrangements of atoms but the same molecular weight