| Dyes | 
        Taken 
          (µg mL–1) | 
        Found 
          (µg mL–1) | 
        Recovery 
          (%) | 
        RSD a 
          (%) | 
        RE 
          (%) | 
        Confidence b 
          Limits | 
       
      
        | BPB | 
        3.00 | 
        3.01 | 
        100.33 | 
        1.621 | 
        1.169 | 
        3.01 ± 0.035 | 
       
      
        | 5.00 | 
        5.02 | 
        100.04 | 
        0.694 | 
        0.940 | 
        5.02 ±     0.047 | 
       
      
        | 7.00 | 
        6.97 | 
        99.57 | 
        0.319 | 
        0.425 | 
        6.97 ± 0.030 | 
       
      
        | BCG | 
        2.00 | 
        2.017 | 
        100.85 | 
        1.134 | 
        1.081 | 
        2.02 ± 0.022 | 
       
      
        | 3.50 | 
        3.51 | 
        100.29 | 
        1.288 | 
        1.228 | 
        3.51 ± 0.043 | 
       
      
        | 5.00 | 
        5.02 | 
        100.40 | 
        0.748 | 
        0.713 | 
        5.02 ± 0.036 | 
       
      
        | BTB | 
        2.00 | 
        2.02 | 
        100.10 | 
        1.460 | 
        1.391 | 
        2.02 ± 0.028 | 
       
      
        | 4.00 | 
        4.01 | 
        100.25 | 
        1.494 | 
        0.426 | 
        4.01± 0.057 | 
       
      
        | 6.00 | 
        5.97 | 
        99.50 | 
        0.671 | 
        0.639 | 
        5.97± 0.038 | 
       
      
        | BCP | 
        2.00 | 
        2.03 | 
        101.50 | 
        0.507 | 
        0.483 | 
        2.03 ± 0.010 | 
       
      
        | 4.00 | 
        4.07 | 
        101.75 | 
        0.902 | 
        0.859 | 
        4.07 ± 0.035 | 
       
      
        | 6.00 | 
        6.05 | 
        100.83 | 
        0.732 | 
        0.698 | 
        6.05 ± 0.042 | 
       
      |