Design and Construction of a Novel Green Optode for Hafnium Determination in Real Environmental Samples: Table 2

Table 2: Application of the proposed and ICP-AES methods to the determination of Hf in real samples.


Sample	Certified value	Measured value^a (ng g⁻¹)		t-test^b	F-value^c
		Proposed	ICP-AES

Standard soil	7.0	6.9 ± 0.3	7.2 ± 0.1	2.11	4.48
	20	27.2 ± 0.6	28.3 ± 0.4	1.86	3.56
	60	59.5 ± 0.4	58.2 ± 0.6	1.59	3.23
	100	100.9 ± 0.5	98.4 ± 0.9	1.88	4.02

Copper based alloy	—	5.0 ± 1.1	5.5 ± 0.9	—	—
	50	54.4 ± 0.7	56.2 ± 1.3	1.48	3.47
	80	86.0 ± 0.5	84.1 ± 1.4	2.24	4.11
	120	124.5 ± 0.8	127.0 ± 1.7	1.65	3.78

Zirconium oxide^d	—	22.0 ± 0.6	22.3 ± 1.8	2.11	3.95
	30	53.2 ± 0.9	51.5 ± 1.6	1.73	3.59
	60	81.1 ± 0.7	84.6 ± 2.1	1.82	4.04
	90	110.7 ± 1.0	115.0 ± 2.4	1.57	3.34

Zirconium oxide^e	—	13.5 ± 0.5	13.2 ± 2.0	1.37	3.69
	40	53.0 ± 0.8	54.0 ± 1.8	1.66	3.81
	80	92.3 ± 0.6	95.7 ± 2.3	1.87	3.96
	120	135.5 ± 0.9	121.8 ± 1.9	2.02	4.13

^aMean ± standard deviation (n = 6). ^bTabulated t-value for five degrees of freedom at P (0.95) is 2.57. ^cTabulated F-value at P (0.95) is 5.05. ^dSold as 99.9% ZrO₂. ^eSold as 99.99% ZrO₂.