BS EN 13320:2002 – Surface active agents — Gas chromatographic trace determination of free ethylene oxide in ethoxylates
1 Scope
This European Standard specifies a test method for the determination of the content of free ethylene oxide in the range from 1 mg/kg to 100 mg/kg in polyglycols, ethoxylates of alcohols and alkylphenols and in fatty acid polyglycol esters.
2 Normative references This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text, and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies (including amendments).
EN ISO 3696, Water for analytical laboratory use – Specification and test methods (ISO 3696:1987). ISO 607, Surface active agents and detergents – Test methods of sample division.
3 Principle The ethoxylates are, after addition of water, analyzed by gas chromatography using a head-space sampling accessory. The free ethylene oxide content is determined by the standard addition test method.
4 Reagents During the analysis, unless otherwise specified, use only reagents of recognized analytical grade and have been checked in advance as to not interfere with the analytical results.
4.1 Water complying with grade 1 as defined in EN ISO 3696.
4.2 Ethylene oxide, C 2 H 4 O, w(C 2 H 4 O) 99,5 %.
4.3 Ethylene oxide, C 2 H 4 O, dissolved in dichloromethane, vials containing 50 mg of ethylene oxide dissolved in 1 ml of dichloromethane.
4.4 N,N-dimethylformamide, C 3 H 7 NO.
5 Apparatus
Ordinary laboratory apparatus and the following.
5.1 Capillary gas chromatograph, with flame ionisation detector (FID) and head-space sampling accessory. The apparatus shall be equipped with a split system. The head-space sampling accessory shall be designed such that each head-space bottle can be thermostated for a defined time.
NOTE Since ethylene oxide is easily decomposed by traces of impurities such as acids and transition metals, (catalysed decomposition), a meticulously clean sampling accessory is necessary .
5.2 Fused silica capillary column, coating: crosslinked dimethylpolysiloxanes, column length 30 m, internal diameter 0,25 mm, film thickness 1,0 .
5.3 Vials, closable by means of a septum, 20 ml, suitable for head-space sampling accessory.
5.4 Septums and aluminium caps, lined with aluminium or polytetrafluoroethylene (PTFE) for closing the vials.
BS EN 13320:2002 – Surface active agents — Gas chromatographic trace determination of free ethylene oxide in ethoxylates