Abstract
Peroxide values (PV) of fat from fallow up formula were determined using redox-potentiometric titration method and standard method, which is based on KI oxidation by hydroperoxides and volumetric titration of liberated iodine, and their uncertainties were compared. Uncertainty sources in measurement, such as sample weight, sodium thiosulfate concentration, and titer, were identified and used as parameters for combined standard uncertainty based on Guide to the expression of uncertainty in measurement and Draft EURACHEM/CITAC Guide. Analytical results and combined standard uncertainties of peroxide values (PV) determined by standard burette and potentiometric titrations were $2.05{\pm}0.17\;and\;1.96{\pm}0.07\;meq/kg$, respectively, suggesting potentiometric titration method is suitable for determining PV of fat with low PV, because uncertainty of PV determination obtained by potentiometric titration was lower than that obtained by burette titration.
본 실험에서는 성장기용 조제식에 함유된 유지를 대상으로 전위차 적정법 및 뷰렛 적정법에 의한 과산화물가를 측정하고 그 측정불확도를 비교하여 산정하였다. GUM(Guide to the expression of uncertainty in measurement) 및 Draft EURACHEM/CITAC Guide의 이론에 기초하여 측정불확도를 구하였으며, 불확도 인자로서 적정액의 농도, 시료량 및 적정량 등이 작용하였다. 뷰렛적정에 의한 과산화물가 측정값과 확장불확도는 $2.05{\pm}0.17\;meq/kg$ 으로 표현되었으며, 전위차적정에 의한 경우는 $1.96{\pm}0.07\;meq/kg$ 으로 표현되었다. 적정과정에서의 측정불확도가 전체불확도의 대부분을 차지하였으며, 전위차적정법에 의한 측정불확도는 뷰렛적정법에 의한 경우보다 낮게 나타나 과산화물가가 낮은 시료의 측정시에 바람직한 측정방법으로 사료되었다.
