|
Sl. No. | Reagent/s used | Methodology | (nm) | Linear range (µg mL−1) ( = L/mol/cm) | Remarks | References |
|
1 | Epichlorohydrin | Measurement of purple colored coupled complex | 405 | 2–22 (0.51 × 104) | Longer reaction time and heating |
[45] |
hydroxyphenacylchloride | 402 | 20–120 (0.10 × 104) |
|
2 | Ethyl vanillin | Measurement of yellow colored hydrazone complex | 410 | 2–16 (7.1 × 103) | — | [46] |
|
3 | Vanillin | Measurement of yellow colored hydrazone complex | 405 | 1–12 | — | [47] |
|
4 | Isatin | Measurement of yellow colored hydrazone complex | 340 | 0–32 (1.2 × 104) | Requires close pH control and 40 min standing time, measurement at a shorter wavelength | [48] |
|
5 | Sodium 1,2-naphthoquinone-4-sulfonate and cetyltrimethyl ammonium bromide | Absorbance of condensation product measured | 500 | 2.0–5.6 | Employs a costly reagent | [49] |
|
6 | Chloranilic acid | Measurement of charge-transfer complex | 500 | 1.37–8.2 | Use of organic solvent, requires heating step |
[50] |
Tetracyanoethylene | 480 | 6.85–34.27 |
2,3-dichloro-5,6-dicyano-1,4-benzoquinone | 580 | 10.96–21.93 |
Thymol blue | Measurement of ion-associate complex | 390 | 6.85–41.13 | Require close pH control, liquid-liquid extraction step |
Bromophenol blue | 410 | 1.37–6.85 |
Bromocresol green | 320 | 1.37–8.22 |
|
7 | 2-Hydroxy-1,4-napthoquinone | Measurement of derivatized product | 365 | 5–25 | Requires close pH control, use of nonaqueous medium, measurement at a shorter wavelength | [51] |
|
8 | 1, 2-Naphthoquinone-4-sulfonate | Measurement of pink colored condensed product | 495 | 0.5–3.0 (1.18 × 104) | Requires close pH control | [52] |
|
9 | 6-Methyl-2-pyridinecarboxaldehyde | Measurement of hydrazone derivative | 328 | 2–16 | Measurement at lower analytical wavelength | [53] |
|
10 | 9-Chloroacridine | Measurement of absorbance of derivatized complex | 500 | — | Requires heating step, time consuming | [54] |
|
11 | 4,4′-Methylene-bis-m-nitroaniline | Measurement of purple colored diazo-coupled complex | 495 | 0.1–15 (5.63 × 104) | Requires low temperature | [55] |
|
12 | 4,4′-Sulphonyldianiline | Measurement of purple colored diazo-coupled complex | 440 335 | 0.5–20 (5.72 × 104) | Requires low temperature | [56] |
|
13 | Tiron-NaIO4 | Measurement of red-colored oxidative-coupled product | 507 | 1.0–15 (1.84 × 104) | Use of multireaction system step | [57] |
|
14 | Tiron-KIO4 | Measurement of red-colored oxidative-coupled product | 505 | 1.5–18 (1.77 × 104) | Use of multistep reaction system | [58] |
|
15 | Uranyl acetate | Measurement of yellow-colored uranyl isonicotinoyl dithiocarbazate complex | 410 | — | Multistep reaction, time consuming | [59] |
|
16 | Neocuproine | Measurement of redox complex | 454 | 0.3–3.5 | Requires close pH control, a multistep reaction | [60] |
|
17 | Rose bengal | Measurement of acetone-chloroform extractable ion-pair complex | 555 | 2.8–5.6 | Requires time consuming and tedious extraction step, use of organic solvent | [61] |
|
18 |
*NBS | Measurement of starch-iodine Complex | 572 | 0.1–3.4 | Multistep reaction, employs an unstable oxidant | [62] |
|
19 |
*NBS | Absorbance of starch-iodine complex measured | 572 | 0.1–3.4 | Multistep reaction, employs an unstable oxidant | [63] |
|
20 | Potassium ferricyanide | Measurement of Prussian blue | 735 | 0.04–8 (3.92 × 104) | — | [64] |
|
21 | 3-(2-Pyridyl)-5,6-diphenyl-1,2,4-triazine | Measurement of redox complex | 558 | 0.62–6.15 | Multistep reaction, requires an expensive reagent | [65] |
|
22 | (a)
*
FC reagent | Measurement of molybdenum-tungsten mixed acid blue absorbance in sodium carbonate medium | 760 | 0.5–10 (1.12 × 10 4) | Simple, rapid, sensitive, uses aqueous medium and extraction free, no use of organic solvent, based on a single step reaction | Present work |
(b) Ferric chloride and potassium ferricyanide | Measurement of absorbance of Prussian blue in acid medium | 760 | 0.2–3.0 (4.55 × 10 4) |
|