| 摘要 |
PURPOSE:To measure the concentration of Na accurately by determining a variation of the concentration of Na corresponding to a deviation in a K concentration between the measuring sample and a standard sample for control to correct the concentration of Na in the measuring sample. CONSTITUTION:Concentrations CK1 and CK2 of Na are determined using a calibration curve L from potential differences E1 and E2 between a selection electrode for Na ions measured for low-concentration and high-concentration reference samples and a reference electrode. The corrected Na concentrations C1 and C2 are determined from the Na concentrations and a K concentration of each reference sample to obtain a corrected calibration curve L'. Then, a measured value ES of the Na ion selection electrode for a sample to be measured is determined on the corrected calibration curve L' to obtain a corresponding Na concentration SNa. Then, an Na concentration S corrected is determined by the formula of S=SNa-k(Sk-Ak) from a K concentration SK of a sample to be measured and Ak of the standard sample for control, wherein the constant k is determined according to an electrode used beforehand. |
