Good day,

Please may someone assist me with the following:

I am using the LAQUA twin Ca2+ meter to measure the Calcium levels in the soil.

In order to do that one needs to use CH3COONH4 for the extraction with a concentration of (1mol/L).

The meter needs to be calibrated with standard solutions but not with the ones that come with the pack but with the new standard solutions as mentioned below:

Calibrate LAQUAtwin B-751 with 150mg/L and 2000mg/L Ca2+ standard solutions which contain the same concentration of CH3COONH4 as in the filtrated samples. (This is part of the methodology)

How much CH3COONH4 needs to be added to the existing standard solution in order to obtain the same concentration as in the filtered sample.

(0.5ml of standard solution is used/ meter for calibration)

Your help will be appreciated.