The standard specifies qualitative and quantitive determination of ethylene oxide and propylene oxide groups in EO and PO adducts, polyethers and polyglycol esters. If a suitable calibration is performed, methoxy groups can also be determined. Ethylene oxide groups convert stoichiometrically into ethyl iodide. However, the conversion of propylene oxide to isopropyl iodide may not be stoichiometric. The alkyl iodides are determined directly from the n-nonane solution by means of gas chromatography using toluene as internal standard.