Dyes RT(Min) k’Aa Rsb Dimethyl yellow 3.86 0.08 0.0 Sudan I 4.71 0.32 1.13 Sudan II 6.94 0.95 2.57 Sudan III 11.08 2.11 4.24 Sudan IV 14.84 3.16 4.45 The efficiency factor (k’A) and resolution coefficient were calculated as per the following formulae: ak’A = tR - tM / tM (where k’A is the capacity factor, tR is the retention time of the analyte and tM is the time taken for the mobile phase to pass through the column). bRs = 2[(tR)B - (tR)A] (Rs is the resolution factor, (tR)B is the RT of peak B, (tR)A is the RT WA+WB of peak A and WA & WB is the peak width of peak A and peak B, respectively).

Table 2: Retention time, resolution coefficient and efficiency factor of the five dyes using present mobile phase.