| Reagent | Nature of reaction | Solvent | Medium Aqueous/Surfactant/Organic | Acidity/pH | λex:λem (nm) | Beer’s Law (μg∙L−1) | Detection Limit (μg∙L−1) | RSD (%) | Interference | Remarks |
| o-phenylenediamine35 | Catalytic oxidation | Bromate | Gallic acid | 4.0 | 415:555 | 0 - 8 | 6.0 | 5.0 | Many, humic acid and Fe3+ | i) Less selective due to much interference ii) Less sensitive iii) Lengthy and time consuming |
| Azomethine-H36 | Catalytic oxidation | potassium bromate | Aqueous | 4.2 | 382:422 | 5.0 × 10−4 - 0.022 | 7.0 | 5 | Fe (III), Ce (IV) | i) Less sensitive ii) Time consuming iii) Less selective due to much interference |
| l-amino-4-hgdroxyanthraauinone37 | Oxidation | Ethanol | Sulfuric acid | 4.2 | 480:575 | 100 - 530 | 50 | 5 | Mo (VI), Fe (III), Ce (IV) | i) Less selective due to much interference ii) Lengthy and time consuming iii)pH dependent |
| rhodamine 6G (R6G)38 | Catalytic Oxidation | EDTA | Sulfuric Acid | 2.5 | 525:555 | 20 - 300 | 2.0 | 4.3 | Many | i) Less sensitive ii) Time consuming iii) Less selective due to much interference iv)pH dependent |
| 2-(α-Pyridyl)-thioquinaldinamide (Present Method) | Oxidation reaction | Ethanol | Acidic medium | 0.05M | 319:371 | 0.001 - 600 | 0.3 ng∙L−1 | 0 - 2 | Nil, using suitable masking agents | i) Ultra sensitive ii) Highly selective iii) Pico-trace levels determination (pg∙g−1) iv) Fluorescence is stable for 24 h. v) Very simple, rapid and non-extractive. vi) No organic toxic and carcinogenic solvents were used. |
| 1,8-diaminonaphthalene39 | Catalytic oxidation | KBr with Tiron | weakly acidic medium | 3.6 - 4.0 | 356:439 | 0.05 - 50 | 8 | 3 | Cu(II) and Fe(III) interfere seriously | i) Time consuming & hence lengthy ii) Less selective due to much interference ii) Less sensitive iii) pH dependent |