A Novel Analytical Method for Trace Ammonium in Freshwater and Seawater Using 4-Methoxyphthalaldehyde as Fluorescent Reagent

Table 1

The FI signals of different concentration standard ammonium solution in existence and in the absence of sodium citrate.

Concentration of ammonium (,  mol/L)	In the absence of sodium citrate	In existence of sodium citrate
0	137.574	138.956
0.100	235.226	227.053
0.200	325.220	319.514
0.300	449.249	437.903
The relationship between FI and	FI = 1025 + 133.06 ()	FI = 989.3 + 132.46 ()