The issue of sodium ion concentration measurement
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This post was last edited by angelzhang720 on 2016-8-12 20:15. What should be done if the sodium ion concentration in water, as measured by a sodium ion meter, is outside the meter’s range? How do you count? What are the pNa and Na conversion formulas?
Dilute the water sample by a certain factor before testing.
Dilute with water free of sodium ions before conducting the measurement. Multiply the concentration obtained by the dilution factor.
What to do if it’s below the lower limit? Are the measured values also inaccurate?
The principle of a sodium ion meter is the same as that of a pH meter. Generally, the measurement range of a sodium ion meter is between 1 ppb and 2300 ppm; for samples with higher concentrations, appropriate dilution or other analysis methods can be used. The mathematical meaning of the pNa concept is the same as that of the pH concept, namely the negative logarithm of the concentration of the ion being measured: pNa = -lg(a Na+), where a represents the concentration value (strictly speaking, the activity value). For example, if the sodium ion concentration is 0.0000001 M, then pNa = 7; this notation is often used in the measurement of ions at very low concentrations.
The sample concentration is lower than the lower limit of measurement by the analyzer, indicating that this measurement method is not suitable for directly determining such samples. Could you appropriately concentrate the sample, or choose another more sensitive analysis method?