Non-linear calibration in quantitative analysis by HPTLC utilizing a fibreoptic fluorescence detector

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.