Abstract
The non-linear calibration in quantitative determinations by high performance thin-layer chromatography utilizing a fibre optic fluorescence detector is examined. Dansyl derivatives of polyamines, as model compounds, are separated in HPTLC silica-gel plates with chloroform:triethylamine (TEA):polyoxyethylene-10-lauryl ether (POLE) (8:4:5%) (v:v:m) as solvent. The obtained calibration graphs show a non-linear relationship between the fluorescence intensity and the quantity of the amine (0-150ng).
The study of the non-linearity shows that the best fits are obtained for the quadratic and cubic regressions. However, for concentrations lower than 50 ng, linear calibrations are obtained with R-squared > 0.99. Furthermore, the principal parameters used to characterize the methods of analysis by HPTLC with fluorescence detection are calculated: sensibility, detection limit, precision, and accuracy.