Research Article
Visual Detection and Determination of Melamine Using Synthetic Dyes
Table 4
Variation in the mole ratio of melamine and alizarin red dye solutions and pH.
| | Mole ratio of alizarin red and melamine (total volume—100 mL) | Concentration | pH | | Alizarin red (M) | Melamine (M) |
| | Melamine | — | 3.29 × 10−4 (41.5 mg dm−3) | 6.19 | | Alizarin red-S | 3.29 × 10−4 (41.5 mg dm−3) | — | 4.49 | | 1 : 1 | 3.29 × 10−4 (41.5 mg dm−3) | 3.29 × 10−4 (41.5 mg dm−3) | 5.18 | | 1 : 2 | 3.29 × 10−4 (41.5 mg dm−3) | 6.58 × 10−4 (83 mg dm−3) | 5.46 | | 1 : 3 | 3.29 × 10−4 (41.5 mg dm−3) | 9.87 × 10−4 (124.5 mg dm−3) | 5.65 | | 1 : 4 | 3.29 × 10−4 (41.5 mg dm−3) | 1.31 × 10−3 (165.2 mg dm−3) | 5.71 | | 1 : 5 | 3.29 × 10−4 (41.5 mg dm−3) | 1.64 × 10−3 (206.8 mg dm−3) | 5.82 |
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