LINEARITY Prepare and analyse not fewer than 4 reference solutions over the calibration range and a blank solution. Perform not fewer than 5 replicates. The calibration curve is calculated by least-square regression from all measured data.
The regression curve, the means, the measured data and the confidence interval of the calibration curve are plotted.
The operating method is valid when:
-the correlation coefficient is at least 0.99 , the residuals of each calibration level are randomly distributed around the calibration curve.
Calculate the mean and relative standard deviation for the lowest and highest calibration level. When the ratio of the estimated standard deviation of the lowest and the highest calibration level is less than 0.5 or greater than 2.0, a more precise estimation of the calibration curve may be obtained using weighted linear regression. Both linear and quadratic weighting functions are applied to the data to find the most appropriate weighting function to be employed. If the means compared to the calibration curve show a deviation from linearity, two-dimensional linear regression is used.
按照我的理解，这里的要求是至少4个线性点和1个空白点，每个点重复测量至少5次，用最小二乘法拟合曲线，相关系数要大于等于0.99，该方法有效，但是下面这一段的描述有点不能理解，计算最低和最高校准水平的平均值和相对标准偏差，这里的最低和最高校准水平是不是第一个浓度点和对打的浓度点？比如我取：空白,1ppm,2ppm,3ppm,4ppm,5ppm,作为标准曲线的取值，那么最低和最高校准水平是不是为1ppm和5ppm两个点？然后是当最低和最高校准水平的估计标准差之比小于0.5或大于2.0时，需要进行加权回归直线。这里的估计标准差，the estimated standard deviation我以前没遇到过，这个值是什么意思？该怎么计算？我查了很久的资料 没查到相关的，唯一有关系的是standard error of estimate，中文翻译为估计标准误差，但是从原英文看应该不是同一个意义的，我自己感觉这个是不是就是S.D.标准差的意思啊？他的estimated是形容词........然后两个校准水平的估计标准差的比值反应什么意义呢？
我的社区
签到
“5·20世界计量日”有奖答题活动邀你来战！
《气相色谱实战宝典》图书免费送！！！
中国科协“优秀科研仪器案例库”作品公示
【有奖征文】第5季“仪器心得”征文活动
