Table 6: Comparison of performance characteristics of the proposed methods with the existing methods.

Sl. No.Reagent/s usedMethodology
Linear range 
(µg mL−1)
( = L/mol/cm)

1EpichlorohydrinMeasurement of purple colored coupled complex4052–22
(0.51 × 104)
Longer reaction time and heating [45]
(0.10 × 104)

2Ethyl vanillinMeasurement of yellow colored hydrazone complex4102–16
(7.1 × 103)

3VanillinMeasurement of yellow colored hydrazone complex4051–12[47]

4IsatinMeasurement of yellow colored hydrazone complex3400–32
(1.2 × 104)
Requires close pH control and 40 min standing time, measurement at a shorter wavelength[48]

5Sodium 1,2-naphthoquinone-4-sulfonate and cetyltrimethyl ammonium bromideAbsorbance of condensation product measured5002.0–5.6Employs a costly reagent[49]

6Chloranilic acid Measurement of charge-transfer complex5001.37–8.2Use of organic solvent, requires heating step [50]
Tetracyanoethylene 4806.85–34.27
Thymol blueMeasurement of ion-associate complex3906.85–41.13Require close pH control, liquid-liquid extraction step
Bromophenol blue4101.37–6.85
Bromocresol green3201.37–8.22

72-Hydroxy-1,4-napthoquinoneMeasurement of derivatized product 3655–25Requires close pH control, use of nonaqueous medium, measurement at a shorter wavelength[51]

81, 2-Naphthoquinone-4-sulfonateMeasurement of pink colored condensed product4950.5–3.0
(1.18 × 104)
Requires close pH control[52]

96-Methyl-2-pyridinecarboxaldehydeMeasurement of hydrazone derivative3282–16Measurement at lower analytical wavelength[53]

109-ChloroacridineMeasurement of absorbance of derivatized complex500Requires heating step, time consuming[54]

114,4′-Methylene-bis-m-nitroanilineMeasurement of purple colored diazo-coupled complex4950.1–15
(5.63 × 104)
Requires low temperature[55]

12 4,4′-Sulphonyldianiline Measurement of purple colored diazo-coupled complex440
(5.72 × 104)
Requires low temperature[56]

13Tiron-NaIO4Measurement of red-colored oxidative-coupled product5071.0–15
(1.84 × 104)
Use of multireaction system step [57]

14Tiron-KIO4Measurement of red-colored oxidative-coupled product5051.5–18
(1.77 × 104)
Use of multistep reaction system[58]

15Uranyl acetateMeasurement of yellow-colored uranyl isonicotinoyl dithiocarbazate complex410Multistep reaction, time consuming[59]

16NeocuproineMeasurement of redox complex4540.3–3.5Requires close pH control, a multistep reaction[60]

17Rose bengalMeasurement of acetone-chloroform extractable ion-pair complex5552.8–5.6Requires time consuming and tedious extraction step, use of organic solvent[61]

18 *NBSMeasurement of starch-iodine Complex5720.1–3.4Multistep reaction, employs an unstable oxidant[62]

19 *NBSAbsorbance of starch-iodine complex measured5720.1–3.4Multistep reaction, employs an unstable oxidant[63]

20Potassium ferricyanideMeasurement of Prussian blue7350.04–8
(3.92 × 104)

213-(2-Pyridyl)-5,6-diphenyl-1,2,4-triazineMeasurement of redox complex5580.62–6.15Multistep reaction, requires an expensive reagent[65]

22(a) * FC reagentMeasurement of molybdenum-tungsten mixed acid blue absorbance in sodium carbonate medium7600.510
(1.12 × 10 4)
Simple, rapid, sensitive, uses aqueous medium and extraction free, no use of organic solvent, based on a single step reactionPresent work
(b) Ferric chloride and potassium ferricyanideMeasurement of absorbance of Prussian blue in acid medium7600.23.0
(4.55 × 10 4)

NBS-N-bromosuccinimide, KMnO4-potassium permanganate, FC reagent-Folin-Ciocalteu reagent.