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Table 1 Effect of experimental parameters on the separation of EBS-Zn (ΙΙ) complex

From: Validated stability indicating liquid chromatographic determination of ebastine in pharmaceuticals after pre column derivatization: Application to tablets and content uniformity testing

Parameter K' N HETP Rs Peak area ratio
Buffer type and pH
Britton Robinson buffer pH  
3 3.41 1036 0.0145 2.73 0.726
3.5 3.92 1034 0.0145 3.58 0.743
4 5.53 2706 0.0055 5.012 0.784
4.5 5.13 2698 0.0055 5.012 0.784
5 3.84 1507 0.0099 4.177 0.752
5.5 3.66 769 0.0195 3.166 0.688
6 3.76 258 0.0581 3.133 0.564
Phosphate buffer pH 4.2 4.26 1479 0.0101 2.72 0.366
Acetate buffer pH 4.2 4.06 1027 0.0146 1.271 0.521
Ratio of aqueous: organic phase(acetonitril: methanol; 1:4)
45:55 4.02 837 0.0179 1.088 0.29
40:60 4.25 1034 0.0145 4.15 0.45
35:65 5.53 2706 0.0055 5.012 0.784
30:70 5.52 2687 0.0056 5.009 0.783
Ratio of acetonitril: methanol
1:4 5.53 2706 0.0055 5.012 0.784
2:3 3.52 1210 0.0124 3.64 0.645
3:2 2.73 2205 0.0068 4.45 0.429
4:1 4.103 1393 0.0108 4.41 0.235
Acetonitril only 5.08 1347 0.0111 4.745 0.198
Methanol only 4.938 1817 0.0083 4.371 0.349
Ionic strength of BRb (Molar)
0.0075 4.256 911 0.0165 3.714 0.48
0.01 5.23 1895 0.0079 4.015 0.69
0.015 5.53 2706 0.0055 5.012 0.784
0.02 5.52 2716 0.0053 5.009 0.782
0.05 5.55 2720 0.0052 5.011 0.783
0.07 4.62 1816 0.0083 4.127 0.642
0.1 4.67 1173 0.0128 4.143 0.513
Flow rate (mL/minute)
0.6 4.348 466 0.0322 2.11 0.92
0.7 4.291 1013 0.0148 2.64 0.84
0.8 4.342 1070 0.0141 2.69 0.75
1 5.53 2706 0.0055 5.012 0.784
1.1 5.26 1982 0.0076 4.857 0.662
1.2 4.74 1486 0.0101 4.33 0.679
1.3 4.25 1057 0.0142 3.21 0.54
1.4 4.12 1013 0.0148 2.94 0.49
1.5 3.97 925 0.0162 2.76 0.33
  1. Where:
  2. K' is the capacity factor; K'= tR - tM/tM
  3. N is the number of theoretical plates;
  4. HETP is the height equivalent to a theoretical plate; HETP = L/N
  5. Rs is the resolution factor;
  6. (t R is the retention time of the complex, t M is the time from injection to the appearance of the solvent front, w 1/2 is the peak width at half height, L is the length of the column, w R and w M are the peak width at base line for the complex and the solvent front respectively)