2-Hydroxy-1-naphthaldehyde-P-hydroxybenzoichydrazone: A New Chromogenic Reagent for the Determination of Thorium(IV) and Uranium(VI)

Table 15

Comparison of the results.

Metal	Reagent	𝜆max; (nm)	pH/medium	Aqueous/extraction	Beer’s law; (μg mL^−1)	𝜀×10^4; L mol^−1 cm^−1	Interference	Reference
U	N-phenyl-3-styrylacrylohydroxamic acid	410	6–6.8	Extraction	1.22–22	1.2	—	[14]
U	5-(2′-carboxyphenyl)azo-8-quinolinol	524	5.2–6.1	Extraction	1.4–7.1	1.035	—	[15]
U	N-phenylcinnamo-hydroxamic acid	400	5.5–8.5	Extraction	—	0.65	—	[16]
U	5-(2′-carboxyphenyl)azo-8-quinolinol in Triton X-100	568	5.2–6.1	Micellar	0.2–3.3	1.5	—	[17]
U	Pyridin-2-carbaxaldehyde 2-hydroxybenzoyl hydrazone	375	3.5–6.1	Extraction	1–5.6		—	[18]
U	Arsenazo-III (in CTAB)	681	3M HClO4	—	1–20 μg g^−1	39	Cr(III), Co(II)	[19]
U	2-Hydroxy-1-naphthaldehyde-p-hydroxybenzoic- hydrazone	410	5.5–6.5	Aqueous	0.476–7.140	1.78	—	Present method
Th	Arsenazo-III	555	2M HclO4	Aqueous	1–60 𝜇g g^−1	30	Ce(III), CN^−, PO4^3−, SCN^−, CH3COO^−	[20]
Th	2-(2-hydroxy-3,6-disulfo-1-naphthylazo)-benzenearsonic acid (Thorin)	578	3M HclO4	Aqueous	0–25 𝜇g g^−1	1.6	—	[21]
Th	1-(2′-thiazolylazo)-2-naphthol	681	2.4–2.8	36% methanol	0.32–6.56	3.14	—	[22]
Th	2-Hydroxy-1-naphthaldehyde-p-hydroxybenzoic- hydrazone	415	5.5–6.5	Aqueous	0.464–6.961	3.5	—	Present method
U&Th	Arsenazo-III (PLS method)	635 & 713	HCl	Aqueous	0.10–1.20	—	—	[23]
U&Th	Carminic acid (bivariate calibration)	590 & 635	6.25	Aqueous	2.50 (U); 1–40 (Th)	—	—	[24]
U&Th	Arsenazo III	679.5 & 684.4	HCl	Aqueous	0.1–0.7 (U & Th)	—	Lanthanides	[25]
U&Th	2-Hydroxy-1-naphthaldehyde-p-hydroxybenzoichydrazone	448 & 477	6	Aqueous	0.238–2.38 (U); 0.232–4.640 (Th)	—	—	Present method