目的 評定超高液相色譜-串聯(lián)質(zhì)譜法（UPLC-MS/MS）測定大鼠尿樣中26-OH-PD濃度的不確定度。方法 分析UPLC-MS/MS法測定大鼠尿樣中26-OH-PD濃度的不確定度來源，根據(jù)各分量計(jì)算出合成不確定度并進(jìn)行了擴(kuò)展。結(jié)果 大鼠尿樣中低濃度（6.16 ng/mL）、中濃度（97.94 ng/mL）和高濃度（398.02ng/mL）26-OH-PD的擴(kuò)展不確定度分別為1.44、6.97、22.05 ng/mL（P=95%，k=2）。結(jié)論 UPLC-MS/MS法測定大鼠尿樣中26-OH-PD低濃度樣品的不確定度主要分別由線性擬合引入，中、高濃度樣品的不確定度主要由儀器允差引入。該法適用于評定UPLC-MS/MS法測定尿樣中26-OH-PD的不確定度研究，能為復(fù)雜生物樣品分析過程的不確定度評定提供一定參考。

Objective To evaluate the uncertainty in 26-OH-PD determination in human urine by UPLC-MS/MS. Methods The whole process of the 26-OH-PD determination was analyzed and the uncertainty from various sources were calculated, and then the combined and expanded uncertainty were also evaluated. Results The expanded uncertainty of 26-OH-PD at low (6.16 ng/mL), medium (97.94 ng/mL) and high (398.02 ng/mL) level was 1.44 ng/mL, 6.97 ng/mL and 22.05 ng/mL (P=95%, k=2). Conclusion Calibration curve fitting was the main source of uncertainty for the low concentration of 26-OH-PD, and instrument tolerance were the main source of uncertainty for the determination of 26-OH-PD at high and medium concentration. This method could be used to evaluate the uncertainty of 26-OH-PD determination in urine. Reference was also provided for the uncertainty evaluation in drug analysis.