Table 2.
Performance characteristics of visible-spectrophotometric and spectrofluorometric methods.
| S.No. | Reagent | Methods | Methods Linear range (µg/mL); molar extinction coefficient, Є (L/mol/cm) | LOD (µg/mL) | LOQ (µg/mL) | Application | Reference |
|---|---|---|---|---|---|---|---|
| 1 | MO | TFH-MO ion-pair extracted into CHCl3 and measured at 422 nm. | 6–12; 1.89×104 | – | – | Tablets | [17] |
| 2 (a) | Mo(V)-SCN− | TFH-Mo(V)-SCN; TFH-OG; and TFH-ARS ion-pair complexes were extracted into organic solvents and absorbance measured at 470, 500 and 425 nm, respectively | 5–75 | – | – | Bulk drug | [18] |
| (b) | OG | 10–80 | – | – | Bulk drug | ||
| (c) | ARS | 5–55 | – | – | Bulk drug | ||
| 3 (a) | BTB | Drug-dye ion pair complexes formed in acid medium extracted into CHCl3 and measured at 410 nm | 2–25; 2.0×105 | 0.24 | 0.71 | Tablets | [19] |
| (b) | BPB | 2–25; 2.0×105 | 0.28 | 0.84 | Tablets | ||
| (c) | BCG | 2–25; 2.0×105 | 0.54 | 1.62 | Tablets | ||
| 4 (a) | CAT-GLN | Unbleached dye color measured at 540 nm | – | – | – | Bulk drug, tablets | [20] |
| (b) | KMnO4-FG FCF | Unbleached dye color measured at 620 nm. | – | – | – | Bulk drug, tablets | |
| (c) | DDQ | Charge-transfer complex formed in acetonitrile measured at 450 nm | – | – | – | Bulk drug, tablets | |
| 5 | Iodine | Drug-I2 charge-transfer complex formed in chloroform measured at 512 nm | 2×10−2–1×10−3 mol/L | – | – | – | [21] |
| 6 | Spectrofluorimetry-Water | Native fluorescence in water was measured at 376 nm after excitation at 275 nm | 0.02–0.05 | 0.0031 | 0.0094 | Tablets, cream, gel and spray, spiked human plasma | [22] |
MO: Methyl orange; Mo(V)-SCN−: Molybdenum (V) thiocyanate; OG: Orange G; ARS: Alizarin red S; BTB: Bromothymol blue; BPB: Bromophenol blue; BCG: Bromocresol green; CAT: Chloramine T; GLN: Gallocyanine; KMnO4: potassium permanganate; FG FCF: fast green FCF; DDQ: 2,3-dichloro-5,6-dicyano-1,4-benzoquinone.