Regulation (EC) No 648/2004 of the European Parliament and of the Council of 31 March 2004 on detergents (Text with EEA relevance) (c. 648)

ANNEX VIII U.K. TEST METHODS AND ANALYTICAL METHODS

3. Determination of non-ionic surfactants in biodegradation test liquors U.K.

3.4. Calculation of results U.K.

Every non-ionic surfactant has its own factor, depending on its composition, particularly on the length of the alkene oxide chain. The concentration of non-ionic surfactant is expressed in relation to a standard substance — a nonyl phenol with ten ethylene oxide units (NP 10) — for which the conversion factor is 0,054.

Using this factor the amount of surfactant present in the sample is found expressed as mg of NP 10 equivalent, as follows:

(b — c) xfx 0,054 = mg non-ionic surfactant as NP 10

where:

b

=

volume of ‘carbate solution’ used by the sample (ml),

c

=

volume of ‘carbate solution’ used by the blank (ml),

f

=

factor of the ‘carbate solution’.