Table 3. Sensing Results of Fe³⁺ Ions in Underground and Tap Water Samples (n = 3).

water samples	added (μM)	measured (μM)	recovery (%)	RSD (%)
underground water	30	29.91 ± 0.13	99.70	0.63
	50	50.16 ± 0.36	100.32	0.99
	100	96.62 ± 0.38	96.62	0.53
	150	142.61 ± 1.08	95.07	1.11
	200	186.47 ± 1.65	93.24	1.26
tap water	30	29.78 ± 0.03	99.27	0.15
	50	49.29 ± 0.12	98.58	0.30
	100	95.74 ± 0.22	95.74	0.34
	150	139.79 ± 1.11	93.19	1.19
	200	184.84 ± 2.50	92.42	1.78