A Modified o-Phthalaldehyde Fluorometric Analytical Method for Ultratrace Ammonium in Natural Waters Using EDTA-NaOH as Buffer

Table 2

The FI of different concentration standard ammonium solution in existence and absence of EDTA.

Concentration of ammonium (, mol/L)	FI in existence of EDTA	FI in absence of EDTA
0	62.871	74.994
0.125	253.749	235.408
0.250	444.613	414.782
0.375	589.166	551.247
0.500	760.241	690.585
The relationship between FI and	FI =	FI =
Corresponding parameters
	0.9973 ( 0.0001)	0.9970 ( 0.0001)
The standard deviation of the intercept	12.65	11.90
The standard deviation of the slope	41.32	38.87