【求助】pH计校正时校正曲线斜率的标准是什么？...

【求助】pH计校正时校正曲线斜率的标准是什么？

自己顶下。求高人指点。

关于三点校正的pH计没有用过，不是很清楚具体的操作
查了一下网络关于Three-point calibration的操作好像有2种，有的是
选择at pH 4.0, 7.0 and 10.0三个pH的缓冲溶液;然后automatically provides offset and two slope adjustments

还有就是The three-point calibration does not require three buffer solutions, but it requires calibration at 2 different temperatures. First the ZERO and SLOPE are determined by normal buffer calibration at standard reference
temperature. Then the buffer solution with a pH value different from the ITP value is warmed up and the intersection with the previously calibrated standard temperature line is calculated.

而关于斜率，有如下：Meter Slope

The slope is an important part of the calibration process. It will verify the accuracy of the calibration performed.

If Meter Displays Slope

Units that display calibration slopes, should have a slope of –57.0 to –62.0 or 57.0 to 62 or 95 to 105. Slope ranges depend on the individual meter.

If Meter Does not Display Slope

Units that do not display calibration slopes should verify the accuracy of the calibration by conducting the following procedure:

Add 5 grams of powdered lime to 100 to 300 mL of room temperature (25° C or 77° F) tap water.
Stir to mix solution.
Take a pH reading. The pH should be between 12.4 and 12.5. If the pH is outside of this range, then the slope is inaccurate and a calibration must be conducted again.

不清楚你们pH计到底什么操作进行三点校正？到底需要几个缓冲溶液？需要用到温度进行校正吗？（已考虑pH温度补偿）

谢谢longbow版主。仪器是梅特勒的SevenMulti，校正时用pH 4.0, 7.0 and 10.0三个pH的缓冲溶液进行。pH计自动进行温度补偿。其正常校正斜率为约59 mV/pH。看来斜率范围应该象斑竹提到的那样，为57 到62 。

再次感谢。

对截距也是有要求的，pH轴上一般不要超过7±0.5，能达到±0.1最好。

请问pH的截距要求在分析化学书上有没有介绍？