OBJECTIVE To evaluate for the uncertainty of the concentration of(C6H5)4BNa(0.02 mol·L?1) titration solution prepared and calibrated according to the method in the Chinese Pharmacopoeia first addition of the 2010 edition. METHODS According to the sources of uncertainty analysis, the measurement model was established and the various influencing factors in the calibration process was evaluated. RESULTS By calculating each fraction of uncertainty in various variable parameters, the relative standard uncertaint...