Schedule 4 ANALYTICAL METHODOLOGY

¹ Acrylamide, epichlorohydrin and vinyl chloride to be controlled by product specification.

² Uncertainty of measurement is a non-negative parameter characterising the dispersion of the quantity values being attributed to a measurand, based on the information used. The performance criterion for measurement uncertainty (k = 2) is the percentage of the parametric value stated in the table or better. Measurement uncertainty must be estimated at the level of the parametric value, unless otherwise specified.

³ If the value of uncertainty of measurement cannot be met, the best available technique should be selected (up to 60%).

⁴ The method determines total cyanide in all forms.

⁵ Values for trueness, precision and uncertainty of measurement are expressed in pH units.

⁶ Reference method EN ISO 8467.

⁷ The performance characteristics for individual pesticides are given as an indication. Values for the uncertainty of measurement as low as 30 % can be achieved for several pesticides, higher values up to 80 % may be allowed for a number of pesticides

⁸ The performance characteristics apply to individual substances, specified at 25% of the parametric value in Table B in Schedule 1.

⁹ The performance characteristics apply to individual substances, specified at 50% of the parametric value in Table B in Schedule 1.

¹⁰ The uncertainty of measurement should be estimated at the level of 3 mg/l of the total organic carbon. CEN 1484 Guidelines for the determination of total organic carbon and dissolved organic carbon must be used.

¹¹ The uncertainty of measurement must be estimated at the level of 1.0 NTU (nephelometric turbidity units) in accordance with EN ISO 7027.

¹ Acrylamide, epichlorohydrin and vinyl chloride to be controlled by product specification.

² Trueness is a measure of systematic error, i.e. the difference between the mean value of the large number of repeated measurements and the true value. Further specifications are those set out in ISO 5725.

³ Precision is a measure of random error and is usually expressed as the standard deviation (within and between batches) of the spread of results from the mean. Acceptable precision is twice the relative standard deviation. This term is further specified in ISO 5725.

⁴ Limit of detection is either three times the standard deviation within a batch of a natural sample containing a low concentration of the parameter; or five times the standard deviation of a blank sample (within a batch).

⁵ The method determines total cyanide in all forms.

⁶ Values for trueness, precision and uncertainty of measurement are expressed in pH units.

⁷ Reference method EN ISO 8467 1995.

⁸ The performance characteristics for individual pesticides are given as an indication. Values for the uncertainty of measurement as low as 30% can be achieved for several pesticides, higher values up to 80% may be allowed for a number of pesticides

⁹ The performance characteristics apply to individual substances, specified at 25% of the parametric value in Table B in Schedule 1.

¹⁰ The performance characteristics apply to individual substances, specified at 50% of the parametric value in Table B in Schedule 1.

¹¹ The performance characteristics apply to prescribed value 4 NTU.

¹² The performance characteristics apply to prescribed value 1 NTU for water leaving surface water treatment works.