I have bought an RQflex® 20 reflectometer instrument with tends to measure the soil nitrate and ammonium but the device gives me unstable results every time I measured
if someone experiences such a device please explain why
Let's go back to first principles:
1. What concentrations are you measuring and how well do they fall within the claimed measurement range?
2. Do you make different standard solutions to calibrate the instrument on the different occasions?
3. Do you make up different batches of KCl and measure the reagent blank?
You must measure the extracts fresh
You might contact the manufacturer and ask if they know what the problem is. Perhaps the manufactured batch has a problem.
No I don't think it likely that these observations are publishable.
Again I appreciate your concern Sir
Regarding your questions
1. What concentrations are you measuring and how well do they fall within the claimed measurement range?
For both ammonium and Nitrate, I use 2 measure range
Ammonium measure range 20-180 mg/l NH4 and 0.2-7.0 mg/l NH4
Nitrate measure range 3-90 mg/l NO3and 5-225 mg/l NO3 g
2. Do you make different standard solutions to calibrate the instrument on different occasions?
I did just the initial calibration without solutions just the blank strip
3. Do you make up different batches of KCl and measure the reagent blank?
You must measure the extracts fresh
I am sorry I mistake in the first answer I only used 0.01 M CaCl2 and I did use the fresh sample extract
You might contact the manufacturer and ask if they know what the problem is. Perhaps the manufactured batch has a problem.
I haven’t tried to contact the manufacturer because I wanted the contact with soil expert because my knowledge of soil is very limited
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