Andrea D. Magrì

Data-fusion for multiplatform characterization of an Italian craft beer aimed at its authentication.

Five different instrumental techniques: thermogravimetry, mid-infrared, near-infrared, ultra-violet and visible spectroscopies, have been used to characterize a high quality beer (Reale) from an Italian craft brewery (Birra del Borgo) and to differentiate it from other competing and lower quality products. Chemometric classification models were built on the separate blocks using soft independent modeling of class analogies (SIMCA) and partial least squares-discriminant analysis (PLS-DA) obtaining good predictive ability on an external test set (75% or higher depending on the technique). The use of data fusion strategies - in particular, the mid-level one - to integrate the data from the different platforms allowed the correct classification of all the training and validation samples.

Tracing the origin of extra virgin olive oils by infrared spectroscopy and chemometrics: A case study

In this paper, the potential of coupling mid- and near-infrared spectroscopic fingerprinting techniques and chemometric classification methods for the traceability of extra virgin olive oil samples from the PDO Sabina was investigated. To this purpose, two different pattern recognition algorithm representative of the discriminant (PLS-DA) and modeling (SIMCA) approach to classification were employed. Results obtained after processing the spectroscopic data by PLS-DA evidenced a rather high classification accuracy, NIR providing better predictions than MIR (as evaluated both in cross-validation and on an external test set). SIMCA confirmed these results and showed how the category models for the class Sabina can be rather sensitive and highly specific. Lastly, as samples from two harvesting years (2009 and 2010) were investigated, it was possible to evidence that the different production year can have a relevant effect on the spectroscopic fingerprint. Notwithstanding this, it was still possible to build models that are transferable from one year to another with good accuracy.

Application of differential scanning calorimetry to the study of drug-excipient compatibility

Abstract Differential scanning calorimetry (DSC) has been used to investigate drug-excipient interactions and, in consequence, their compatibility. In particular, binary mixtures of nefazodone with magnesium stearate and lactose, and fosinopril with the same excipients were prepared and analysed, after proper conditioning. The thermoanalytical results were compared with those obtained by spectroscopic (UV, IR) and chromatographic (HPLC) analysis. We believe that changes in DSC runs cannot always be a sufficient condition to prove that some interaction occurs between drug and excipient during storage at room temperature. Some data on the spectroscopic characteristics of nefazodone and fosinopril drugs and their thermal behaviour are also reported.

Determination of fosinopril in pharmaceutical formulations containing hydrochlorothiazide by multiwavelength UV spectrophotometry

A sensitive, simple, rapid and precise method for the simultaneous determination of fosinopril (FOS) and hydrochlorothiazide (HCT) in pharmaceutical formulations is presented. These active ingredients are extracted in aqueous solution and measured by multiwavelength UV spectrophotometry using the program QUEST. HCT acts as an internal standard to verify the accuracy of the analysis. Some aspects of the chemical, spectroscopic and thermoanalytical behaviour of FOS are also reported.

Complexes of divalent metal ions with cinchomeronic and dinicotinic acid thermal properties

Abstract The thermal properties of the complexes of cinchomeronic and dinicotinic acid with several divalent metal ions were determined by thermogravimetry (TG) and differential thermal analysis (DTA). For the thermal stability of the anhydrous compounds a sequence may be observed for the metal ions with cinchomeronic (3,4-H 2 PC) and dinicotinic acid (3,5-H 2 PC): The thermal stability of the pyridine carboxylic acid for each metal of the series is: dinicotinic > cinchomeronic The activation energy values for each thermal reaction were also calculated, using the Coats and Redfern algorism, by the Univac 1108 computer, by a program properly implemented for the statistical analysis of the data to obtain the reaction order and the activation parameters with the relative confidence limits.

Complexes of cobalt(II), nickel(II) and copper(II) with the benzenedicarboxylic acids. Thermal properties

Abstract The thermal properties of the complexes of phthalic, isophthalic and terephthalic acid with cobalt(II), nickel(II) and copper(II) are determined by thermogravimetry (TG), differential thermogravimetry (DTG) and differential scanning calorimetry (DSC). The thermal stability of the anhydrous compounds gives, for the metal ions, a sequence Co > Ni > Cu. The thermal stability series as a function of the ligand for each metal is terephthalate > isophthalate > phthalate.

Classification and Class-Modelling

Abstract This chapter describes the basic theory about classification, starting from a general description of the different approaches to classification and then illustrating in detail the principal methods which are used in the framework of assessment of food quality. Examples of application of the methods to different data sets are also provided.

Coordination compounds of biological interest: thermal properties of some compounds of saccharin (o-benzoic sulfimide) with divalent metal ions

The thermal properties of cobalt(II) and copper(II) complexes of saccharin (sacc) (o-benzoic sulfimide) have been studied, and are compared with those of ternary complexes of cobalt(II) and copper(II) having both saccharin and pyridine as ligands. The thermal behaviour is discussed in terms of the bonds between the central ion and the ligands. The frequency shifts of the carbonyl and sulfonyl groups support the hypotheses derived from the thermal data. The thermal stability scale CO(II) /s> Cu(II) is always obtained while the stability constant scale is CO(II) < Cu(II).

Use of near infrared reflectance and transmittance coupled to robust calibration for the evaluation of nutritional value in naked oats

A rapid accurate and precise method for simultaneous determination of β-glucan and protein content in naked oat samples, based on the coupling of near-infrared spectroscopy and chemometrics, is presented. In particular, three different spectroscopic approaches [near infrared reflectance (NIR) and transmittance (NIT) on flour and NIT on whole grains] and various spectral pretreatments were considered. To account for the possibility of outlying samples, a robust version of the PLS algorithm (namely partial robust M-regression) was used. All the models resulted as accurate as the reference methods, reflectance spectroscopy being the technique providing the best outcomes. Variable reduction by inclusion of the most relevant predictors only (as evaluated by VIP scores) resulted in simpler and, in one case, more parsimonious models, without loss in accuracy.

Using thermoanalytical data: Part 1. The power of kinetic parameters determined from thermogravimetry to describe the experimental behaviour of the sample

Abstract Sources of misunderstandings when evaluating kinetic parameters from thermogravimetric (TG) curves are discussed. A simple method for calculating Arrhenius parameters, suitable for implementation on a PC connected to the TG apparatus, is presented. The results obtained with calcium oxalate are discussed with respect to their ability to predict thermal behaviour in several experimental conditions: agreement with experimental data is satisfactory. This is not so when using some literature-cited kinetic parameters, which fail to represent the same TG curves from which they are extracted. Suggestions are derived for design of a modern TG apparatus connected to a PC.