Sensitive Spectrophotometric Determination of Atenolol in Pharmaceutical Formulations Using Bromate-Bromide Mixture as an Eco-Friendly Brominating Agent

Table 1

Comparison of the proposed and the existing visible spectrophotometric methods.

Sl. No.	Reagent/s used	Reagent used	𝜆max; (nm)	Linear range,; μg/mL and; ε, L/mol · cm	LOD,; μg/mL	Reaction time, min	Remarks	Reference
(1)	Hydroxylamine hydrochloride-iron (III)	Ferric hydroxamate complex measured	510	50–800 (𝜀=5.3×10^2)	NR	20–30	Less sensitive, heating required	[51]
(2)	Chloranilic acid	Charge transfer complex measured	534	25–250	NR	—	Less sensitive, use of organic solvents	[52]
(3)	Chloranilic acid	Charge transfer complex measured	530	10–280	NA	NA	-do-	[53]
(4)	Acetaldehyde-Chloranil		690	NA	NA	NA	Use of organic solvents	[54]
(5)	NH4VO3	Reaction rate measured	750	NA	NA	NA	Heating required	[55]
(6)	4-chloro-7-nitrobenzo-2-oxa-1,3-diazole	Coupling product measured as a function of time	460	5–50	1.3	30	Heating required	[56]
(7)	Potassium permanganate- in alkaline medium	Unreacted KMnO4 measured	526			4 hrs	Time-consuming, involve judicial control of many experimental variables	[57]
		Rate-constant method		6.66–10.65
		Fixed-concentration method		6.66–5.33
		Fixed-time method		6.66–7.99
(8)	Sodium nitroprusside	Complex of ammonia and nitroprusside measured	495	0.5–30 (𝜀=3.01×10^5)	0.01	5	Heating required	[58]
(9)	Chloramine-T-metol-sulphanilic acid	Unreacted chloramine-T measured	520	2.5–25 (𝜀=3.24×10^3)	2.34	20	Less sensitive	[59]
(10)	Chloramine-T:
	(a) Metanil yellow	Unreacted chloramine-T measured	530	1–12; (𝜀=1.19×10^4)	0.32	10		[60]
	(b) Indigo carmine		610	2.5–20 (𝜀=6.65×10^3)	0.04	10
(11)	Bromate-bromide mixture- methyl orange	Unreacted bromine measured	520	0.5–4.0 (𝜀=4.13×10^4)	0.07	15		[61]
(12)	Phenol red	The change in the color of phenol red measured	430	3.0–30 (𝜀=3.47×10^3)	4.61	—	Less sensitive	[62]
(13)	Bromate-bromide mixture:						Simple, sensitive and no heating step. No; use of organic; solvent. Use of an eco-friendly brominating reagent.	This; work
	(a) MCP	Unreacted MCP in acid measured	540	1.0–20.0 (𝜀=1.20×10^4)	0.12	15
	(b) MCP	Bromo-derivative of MCP measured	445	2.0–40.0 (𝜀=4.51×10^3)	0.56	10
	(c) EGC	Unreacted EGC in acid measured	630	1.0–8.0 (𝜀=3.46×10^4)	0.05	10

MCP: metacresol purple, EGC: erioglaucine, NR: not reported, NA: not available.