4 Convert components to standard u(Rw) = 2.6 % uncertainty u(x) 5 Calculate combined standard uncertainty, uc uc = = 5.2 % 6 Calculate expanded uncertainty, Example B: BOD in wastewater – results of internal quality control and inter-laboratory comparison results (Magnusson et al, 2004) Estimation of uncertainty was based on the results obtained in internal quality control and in participating in Inter-laboratory comparisons. Step Action Example: BOD in wastewater 1 Specify Measurand BOD in wastewater, measured with EN1899-1 (method with dilution, seeding and ATU). The demand on uncertainty is ± 20 %. 2 Quantify u(Rw) A: The control sample, which is a CRM, gives an s of 2.6 % at a level of 206 mg/L O2. s = 2.6 % is also used as s when setting the control chart A control sample limits. B possible steps not B: The analysis of the control sample includes all analytical steps after covered by the control sampling sample 3 Quantify Method and RMSbias = 3.76 laboratory bias Data from the Table above (results of comparisons) 4 Convert components to standard uncertainty u(x) u(Rw) = 2.6 % 5 Calculate combined uc = % standard uncertainty, uc 6 Calculate expanded uncertainty,
4 Convert components to standard uncertainty u(x) u(Rw) = 2.6 % 5 Calculate combined standard uncertainty, uc uc = = 5.2 % 6 Calculate expanded uncertainty, Example B: BOD in wastewater – results of internal quality control and inter-laboratory comparison results (Magnusson et al, 2004) Estimation of uncertainty was based on the results obtained in internal quality control and in participating in Inter-laboratory comparisons. Step Action Example: BOD in wastewater 1 Specify Measurand BOD in wastewater, measured with EN1899-1 (method with dilution, seeding and ATU). The demand on uncertainty is ± 20 %. 2 Quantify u(Rw) A control sample B possible steps not covered by the control sample A: The control sample, which is a CRM, gives an s of 2.6 % at a level of 206 mg/L O2. s = 2.6 % is also used as s when setting the control chart limits. B: The analysis of the control sample includes all analytical steps after sampling 3 Quantify Method and laboratory bias Data from the Table above (results of comparisons) RMSbias = 3.76 4 Convert components to standard uncertainty u(x) u(Rw) = 2.6 % 5 Calculate combined standard uncertainty, uc uc = % 6 Calculate expanded uncertainty,
PLC-6_Guidelines_oct2015_rev0117_to%20RedCore%2015_HazSub%20comments.docx