Chromatographic-Densitometric Analysis of Chosen Fluoroquinolones on TLC Plates Using Mobile Phases with Different Viscosity

TLC-densitometric method was developed for the identification and quantitative determination of selected fluoroquinolones. Silica gel TLC 60 F254 plates were used as the stationary phase. For the separation of examined compounds the suitability of the following four mobile phases with different dynamic viscosity was checked: (I) methanol:ammonia:ethyl acetate:acetonitrile 1:1:2:1 v/v/v/v (1.70 mPa · s), (II) dichloromethane:methanol:isopropanol:ammonia 4:4:5:2 v/v/v/v (2.08 mPa · s), (III) dichloromethane:ethanol:toluene:ammonia:n-butanol:water 6:6:2:1.8:3:0.3 v/v/v/v/v/v (2.27 mPa · s), (IV) 1,4- dioxane:ammonia:tetrahydrofuran 6:3:2 v/v/v (3.24 mPa · s). The calculated values of retardation factors RF, capacity factors k, selectivity factors α, resolution factors Rs, and also asymmetry factors As for the evaluation of separation conditions were used. The obtained results confirmed that dynamic viscosity of the mobile phases is essential and influences the retention parameters of the studied fluoroquinol...