Information concerning the uncertainty associated with the reference concentration

DIN 1076 quotes an estimated value of 3% for the uncertainty associated with the reference concentration in the dynamic test gas stream. This value can also be assumed when samplers are charged by means of a gas collecting tube. If samplers are charged by spiking, the uncertainty associated with the concentration of the spiking solution is 3% in unfavourable cases. Since, however, sampling is not realistically replicated in the case of spiking, this fact should be accounted for by choosing a slightly larger estimated value for the uncertainty associated with the reference concentration in cases where the samplers are spiked (5%).

Examples of the calculation of the uncertainty associated with the concentration of the spiking solution.

example 1
deviation [%] standard uncertainty [%]
  random not-random random not-random
volume measuring device        
flask 1 rel. dev. 0.5 rel. dev. 0.58 0.29
flask 1 rel. dev. 0.5 rel. dev. 0.58 0.29
piston-driven micropipette 0.4 rel. dev. 1 rel. dev. 0.40 0.58
piston-driven micropipette 0.4 rel. dev. 1 rel. dev. 0.40 0.58
piston-driven micropipette 0.4 rel. dev. 1 rel. dev. 0.40 0.58
          0.00 0.00
purity of chemical agent 0.6 rel. dev. 99 rel. dev. 0.60 0.58
ucc [%] 1.73


example 2
deviation [%] standard uncertainty [%]
  random not-random random not-random
volume measuring device        
volumetric cylinder 1 rel. dev. 1.5 rel. dev. 0.58 0.87
volumetric cylinder 1 rel. dev. 1.5 rel. dev. 0.58 0.87
piston-driven micropipette 0.4 rel. dev. 1 rel. dev. 0.40 0.58
piston-driven micropipette 0.4 rel. dev. 1 rel. dev. 0.40 0.58
microliter syringe 1 rel. dev. 1 rel. dev. 1.00 0.58
microliter syringe 1 rel. dev. 1 rel. dev. 1.00 0.58
purity of chemical agent 0.6 rel. dev. 97 rel. dev. 0.60 1.73
ucc [%] 3.03


example 3
deviation [%] standard uncertainty [%]
  random not-random random not-random
volume measuring device        
volumetric cylinder 1 rel. dev. 1.5 rel. dev. 0.58 0.87
volumetric cylinder 1 rel. dev. 1.5 rel. dev. 0.58 0.87
piston-driven micropipette 0.4 rel. dev. 1 rel. dev. 0.40 0.58
piston-driven micropipette 0.4 rel. dev. 1 rel. dev. 0.40 0.58
dispenser 0.5 rel. dev. 1 rel. dev. 0.50 0.58
dispenser 0.5 rel. dev. 1 rel. dev. 0.50 0.58
purity of chemical agent 0.6 rel. dev. 97 rel. dev. 0.60 0.58
ucc [%] 2.77