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

Table 3

The matrix spiked recoveries of the proposed method.

Samples	Spiked concentration of ammonium	Determination results of the samples ()	Recoveries
Seawater	—	0.127 ± 0.007 μmoL/L	—
	0.125 μmol/L	0.248 ± 0.010 μmoL/L	96.6%
	0.175 μmol/L	0.316 ± 0.017 μmoL/L	108.1%
Mountain spring water	—	0.089 ± 0.004 μmoL/L	—
	0.125 μmol/L	0.207 ± 0.007 μmoL/L	94.4%
	0.175 μmol/L	0.255 ± 0.012 μmoL/L	94.9%
Groundwater	—	0.062 ± 0.003 μmoL/L	—
	0.125 μmol/L	0.179 ± 0.004 μmoL/L	93.6%
	0.175 μmol/L	0.240 ± 0.008 μmoL/L	101.7%