ABSTRACT
<p><b>AIM</b>To set out the procedure for estimation of measurement uncertainty for the determination of ginsenosides R(g1), Re and R(b1) in Radix ginseng by HPLC.</p><p><b>METHODS</b>To facilitate the identification and analysis of the uncertainty sources arising from the procedure of analysis, a cause and effect diagram was constructed and simplified. Each uncertainty component whether associated with individual sources or with the combined effects of several sources, was evaluated with respect to the significance of its contribution to the overall measurement uncertainty and was expressed as standard uncertainty. All the standard uncertainties were then combined according to the appropriate rules to give a combined standard uncertainty and an expanded standard uncertainty. Results The expanded standard uncertainties for the HPLC determination of ginsenoside R(g1), Re, and R(b1), are 0.12c, 0.14c and 0.13c, respectively.</p><p><b>CONCLUSION</b>Measurement uncertainty is applicable to set the limit of the ginsenosides in Radix ginseng. The establishment of the methodology for the evaluation of measurement uncertainty is important to the studies of Chinese materia medica standards.</p>