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Table 4 Results in evaluation of robustness and ruggedness of PCA and DDQ methods (expressed in %RSD)

From: Application of two charge transfer complex formation reactions for selective determination of metformin hydrochloride in pharmaceuticals and urine

Method MEB taken, μg mL-1 Robustness Ruggedness
Conditions altered
Volume of reagent (mL)a Reaction time alteredb Inter-analysts’ (n = 3) Inter-instruments’ (n = 3)
PCA method 160.0 0.96 0.72 0.76 1.82
200.0 0.87 1.14 0.66 1.89
240.0 2.98 0.81 0.88 1.07
DDQ method 32.0 0.64 0.69 0.62 0.78
40.0 0.89 0.91 0.47 1.53
48.0 1.68 0.54 1.44 1.51
  1. aThe volumes of PCA or DDQ added were 1 ± 0.2 mL. bReaction times were 10 and 10 ± 1 min (with PCA) and 2.0 and 2 ± 0.5 min (with DDQ)