The non-linear calibration in quantitative determinations by high performan
ce thin-layer chromatography utilizing a fibre optic fluorescence detector
is examined. Dansyl derivatives of polyamines, as model compounds, are sepa
rated in HPTLC silica-gel plates with chloroform:triethylamine (TEA):polyox
yethylene-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 th
e quadratic and cubic regressions. However, for concentrations lower than 5
0 ng, linear calibrations are obtained with R-squared > 0.99. Furthermore,
the principal parameters used to characterize the methods of analysis by HP
TLC with fluorescence detection are calculated: sensibility, detection limi
t, precision, and accuracy.