Determination of total nonionics and polyethylene glycols

Polyethoxylates may contain polyethylene glycols as well as ethoxylated alcohols, alkylphenols, etc. Both types of component are determined by the Weibull method [10], which has been adopted as an international standard [11], reference to which is advised. The following is an abbreviated version. The method can be used for fatty acid ethoxylates, but the ethyl acetate extract will include any free fatty acid present in the sample. 

Weigh about 5g of the sample and dissolve it in 100 ml ethyl acetate (caution flammable) at 35°C in a separating funnel. 

Extract with three 100 ml portions of 30% sodium chloride solution at 

Wash each extract twice with 100 ml ethyl acetate, also at 35 C. 

Evaporate the ethyl acetate to dryness in a tared beaker and dry to constant weight. 

---