classified according to the nature of the hydrophilic portion of the
molecule:
(i)anionic– in these, which include soaps, alkyl and alkylbenzene
sulfonates and alcohol sulfates, the hydrophilic portion is a
negatively charged ion produced in solution. They are incom-
patible with the use of quaternary ammonium compounds
(QUATs) which are positively charged;
(ii)non-ionic– made by condensing ethylene oxide on to the polar
end of a fatty acid, fatty alcohol or alkyl phenol;Figure 11.9 Two-stage cleaning.
(Reproduced with permission from WHO document VPH/83.42, copyright
retained)
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