In order to transfer a calibration model, techniques such as piecewise direct standardization (PDS) or direct standardization (DS) are used. This implies that the same subset of samples must be measured in both situations. However, when a model is transferred from an off-line application to an on-line application, it is not possible to remeasure the same subset of samples. In this paper, howeve...

PURPOSE In this work a numerical method, based on the use of spectrophotometric data coupled to partial least squares (PLS) regression and net analyte preprocessing combined with classical least square (NAP/CLS) multivariate calibration, is reported for the simultaneous determination of metformin hydrochloride (MET), gliclazide (GLZ) and pioglitazone hydrochloride (PIO) in synthetic samples and...

This presented paper deals with application of three multivariate calibration methods methods for simultaneous spectrophotometric determination of two active substances in combined pharmaceutical formulation, composed of rutin (RU) and ascorbic acid (AA). The multivariate methods are classical least squares (CLS), principal component regression (PCR) and partial least squares (PLS). The results...

a r t i c l e i n f o Keywords: Calibration free laser-induced breakdown spectroscopy (CF-LIBS) Multi-element analysis Oxides The quantitative determination of oxide concentration by laser-induced breakdown spectroscopy is relevant in various fields of applications (e.g.: analysis of ores, concrete, slag). Calibration free laser-induced breakdown spectroscopy and the multivariate calibration ar...

Three methods are presented for simultaneous determination of ibuprofen and paracetamol without previous separation. The first method depends on first derivative UV spectrophotometry, with zero-crossing measurement. The first derivative amplitudes at 230 and 290 nm were selected for the assay of ibuprofen and paracetamol, respectively. The second method depends on first derivative of the ratio-...

Resolution of binary mixtures of metoprolol and propranolol without sample pretreatment has been successfully achieved, using three different methods. The first method was based on application of Vierodt’s method that involves measurements of the absorbances at 222.6 and 213.4 nm for metoprolol and propranolol. Calibration graphs were established in the range of 1-70 μg/mL and 0.5-30 μg/mLfor m...