Thionine-Bromate as a New Reaction System for Kinetic Spectrophotometric Determination of Hydrazine in Cooling Tower Water Samples

Table 3

The recovery results on the determination of hydrazine in the different water samples using the proposed method and the standard ASTM method.

	Hydrazine (𝜇g mL^−1)
Sample	Proposed method			ASTM method			Statistical test
	Added	Found^a	Recovery (%)	Added	Found^a	Recovery (%)	𝑡 test^b
Distilled water	1.0	1.01 ± 0.01	102.0	1.0	0.99 ± 0.01	99.0	3.40
	5.0	4.98 ± 0.05	99.6	5.0	5.01 ± 0.03	100.2	1.04
Drinking water	1.0	0.99 ± 0.03	99.0	1.0	1.01 ± 0.01	101.0	1.15
	5.0	5.03 ± 0.04	100.6	5.0	4.98 ± 0.05	99.6	2.16
	—	2.12 ± 0.02		—	2.09 ± 0.02		2.59
Cooling tower water (1)	1.0	3.14 ± 0.03	100.6	1.0	3.08 ± 0.03	98.7	3.46
	5.0	7.05 ± 0.08	99.0	5.0	7.15 ± 0.08	102.4	2.16
	15.0	17.19 ± 0.15	100.4	15.0	17.38 ± 0.18	101.7	2.19
	—	2.25 ± 0.02		—	2.27 ± 0.02		1.73
Cooling tower water (2)	10.0	12.19 ± 0.11	99.5	10.0	12.28 ± 0.12	100.9	1.42
	20.0	22.31 ± 0.21	100.3	20.0	22.08 ± 0.19	99.6	1.89

^aMean ± standard deviation (𝑛=3).
^bTabulated 𝑡-value for three replicate determinations at 𝑃 (0.95) is 4.30.