Analytical methods

Analytical methods development for pharmaceutical drugs

Team: João Lopes, Jorge Sarraguça, Silvana Moreira

The development of new analytical methods, no matter what experimental technique to be used, aim at the determination of chemical species at the most efficient way possible both in time, money and reagents, and with the smallest environmental cost. Chemometrics techniques can contribute substantively for this goal.
By resorting to Experimental Design in the planification step of the experiments, a reduced number of experiments is needed to optimize experimental conditions and setup, necessary for increasing the signal to noise ratio and the time of analysis (e.g in flow analysis and in chromatography). By applying multivariate analysis techniques, the important factors and interactions between factors to be optimized can be determined and optimal conditions of analysis can be obtained, which hardly could be achieved by univariate analysis of experiments where ultimately sub-optimal conditions are used.
Multivariate methods can extract meaningful patterns, estimate confidence and prediction intervals, and use constrains to prevent unreal model solutions. Depending on the data and on the information needed an number of multivariate methods can be applied, for exemple, the use of multivariate curve resolution (MCR), principal component analysis (PCA) or partial least squares (PLS) in the analysis of experimental results obtained from flow analysis experiments (e.g with electrochemical or chemiluminescence detection) or HPCL can be usefull in reducing significantly the time necessary for the analysis of mixtures with the simultaneous determination of different chemical species even when the analytical signals are not resolved.


  • Couto M.C.M., Pinto I., Madureira T.V., Rocha M.J., Tiritan M.E., Lopes J.A. and Almeida A.A. (2014), Lower Douro river basin (Portugal) water quality – Focus on trace element changes and anthropogenic sources of contamination, Global NEST Journal,16(2), 251-267
  • Ribeiro DSM, Lopes JA, Santos JLM, Prior JAV* (2012) Exploiting adsorption and desorption at solid-liquid interface for the fluorometric monitoring of glibenclamide in adulterated drinks, Anal. Chim. Acta, 721, 97-103
  • Lopes SB, Sarraguça JMG, Prior JAV, Lopes JA* (2012) Development of an HPLC assay methodology for a desonide cream with chemometrics assisted optimization, Anal. Lett., 45(11), 1390-1400
  • Pires AR, Araújo AN, Lopes JA, Montenegro MCBSM* (2009) Simultaneous determination of thiamine and pyridoxine in mutivitaminics by Sequential Injection Analysis (SIA) with potentiometric detection, Anal. Lett., 42, 1923-1939
  • Ribeiro DSM, Prior JAV*, Lopes JA, Santos JLM, Lima JLFC (2009) Exploiting the Oxidative Coupling Reaction of MBTH for Indapamide Determination, Talanta, 79, 1161-1168
  • Marques KL*, Santos JLM, Lopes JA, Lima JLFC (2008) Simultaneous chemiluminometric determination of levodopa and benserazide in a multi-pumping flow system with multivariate calibration, Anal. Sci., 24(8), 985-991
  • Ribeiro JPN, Lopes JA, Fachini A* (2008) Cleansing contaminated seawaters using marine cyanobacteria: evaluation of the trace metal removal from the medium, Intern. J. Environ. Anal. Chem., 88(10), 701-710
  • Sarraguça JMG*, Lopes JA, Santos JLM, Lima JLFC (2012) Mathematical simulation of signal profiles in flow analysis, Anal.Lett., 45(1), 85-98
  • Rodrigues SM, Marques KL, Lopes JA*, Santos JLM, Lima JLFC (2010) Mathematical Modeling of Dispersion in Single Interface Flow Analysis, Anal. Chim. Acta, 663, 178-183
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