Gran作图法是离子选择性电极的一种常用测试方法,特别是被测离子浓度较低时,它能获得精确度较高的结果。但这一方法同其它的绘图求解法一样,容易产生人为的作图误差。尤其这一方法是利用延长线交轴法求值,这就要求对试验点的舍取和联线必须细心、准确,稍有偏斜就会给结果带来大的误差。况且试验点的取舍和联线均靠经验和眼睛观察来确定,这显然会降低Gran作图法的准确性和可靠性。如今袖珍计算器已普及,这 Granography is a common test method for ion-selective electrodes, especially when the measured ion concentration is low, which results in a more accurate result. However, this method, like other graphical solutions, is prone to artifactual errors. In particular, this method is to use the extension line cross-axis method of evaluation, which requires the test point of the rounding and line must be careful, accurate, a slight deflection will bring big errors to the results. Moreover, the choice and connection of test points are based on experience and eye observation to determine, which will obviously reduce the accuracy and reliability of Gran mapping. Pocket calculators have become popular today