Baselines are often chosen by visual inspection of their effect on selected spectra. A more objective procedure for choosing baseline correction algorithms and their parameter values for use in statistical analysis is presented. When the goal of the baseline correction is spectra with a pleasing appearance, visual inspection can be a satisfactory approach. If the spectra are to be used in a sta...

Chemometrics has been used for some 30 years but there is still need for disseminating the potential benefits to a wider audience. In this paper, we claim that proper analytical chemistry (1) must in fact incorporate a chemometric approach and (2) that there are several significant advantages of doing so. In order to explain this, an indirect route will be taken, where the most important benefi...

Neste artigo, é proposta uma nova técnica para transferência de calibração, que combina o Algoritmo das Projeções Sucessivas (APS) para seleção de variáveis robustas com a técnica de sub-amostragem e agregação de modelos conhecida como subagging. A técnica proposta tem por objetivo construir modelos de Regressão Linear Múltipla (RLM) que sejam robustos com respeito a diferenças na resposta inst...

Four spectrophotometric methods are described and applied to resolve ternary mixtures of the corticosteroid Dexamethasone (DEX), the antibiotic Polymyxin B (PLX) and its encouraging Trimethoprim (TMP). The simultaneous determination of these three compounds was firstly accomplished by a derivative method using the “ratio spectrum-zero crossing derivative” (satisfactory results in synthetic mixt...

One paramount challenge in multi-ion-sensing arises from ion interference that degrades the accuracy of sensor calibration. Machine learning models are here proposed to optimize such multivariate However, acquisition big experimental data is time and resource consuming practice, necessitating new paradigms efficient for these data-limited frameworks. Therefore, a novel approach presented this w...

This paper proposes the use of least-squares support vector machines (LS-SVMs) as a relatively new nonlinear multivariate calibration method, capable of dealing with ill-posed problems. LS-SVMs are an extension of "traditional" SVMs that have been introduced recently in the field of chemistry and chemometrics. The advantages of SVM-based methods over many other methods are that these lead to gl...

This paper presents the application of the bagging technique for non-linear regression models to obtain more accurate and robust calibration of spectroscopy. Bagging refers to the combination of multiple models obtained by bootstrap re-sampling with replacement into an ensemble model to reduce prediction errors. It is well suited to “non-robust” models, such as the non-linear calibration method...