Systematic and statistical errors in quantitative evaluation in TLC and HPTLC. 4. Linear calibration

Abstract

SummaryAnalytical results are often obtained from reflectance or fluorescence measurements in TLCor HPTLC with the aid of calibration lines. Curve fitting may not be done by conventional least squares methods for both the independent and the dependent variables are erroneous; errors occur in the volumes spotted on to the plate and in the reflectance/fluorescence measurements. Therefore the sum of the squares of the distances to the calibration line has to be minimized instead of the squared sum of the errors of the dependent variable. The algorithms used are derived and explained. Implications of error propagation for the analytical result are also given.

Pharmaceuticals and Drugs

“…This nonlinearity is valid for both peak height and peak area measurements. A detailed interpretation of the problems is presented in the papers of Ebel and coworkers (149)(150)(151)(152)(153)(154)(155)(156).…”