Ronei J Poppi

University of Campinas | UNICAMP · Departamento de Química Analítica

This study aimed at developing a non-invasive and rapid method to determine the authenticity of plant-based protein powders (free of soy, lactose, and gluten), and classify possible adulterations in the powders using near-infrared spectroscopy (NIR) and chemometric tools. Three potential powder adulterants were investigated: soy protein, whey (lact...

The antibiotic moxifloxacin had a recent surge in its use due to its broad spectrum of activity. However, due to the low metabolization inside the organism, it became an environmental concern. Here, the photolytic degradation of moxifloxacin antibiotic in alkaline medium was carried out and monitored through SERS spectroscopy. Multivariate curve re...

The identification of key components relevant to sensory perception of quality from commercial chocolate samples was accomplished after chemometric processing of GC×GC-MS (Comprehensive Twodimensional Gas Chromatography with Mass Spectrometric Detection) profiles corresponding to HS-SPME (Headspace Solid Phase Microextraction) extracts of the sampl...

Beeswaxes are interesting solid lipids for the development of nanostructured lipid carriers (NLC), and their origin can be either natural or synthetic. Due to this difference, their performance should be distinct and unstable formulations can be generated. The objective of this work was to investigate miscibility and structural changes (polymorphis...

This work demonstrated that a Ni-P film deposited on polydimethylsiloxane (PDMS) substrate could influence the magnetic aggregation of gold-modified magnetic nanoparticles (Fe3O4/AuNPs), improving their performance in surface-enhanced Raman scattering (SERS) detection. A simple and low-cost electroless deposition process was used to deposit the Ni-...

Cocoa butter provides desirable sensory properties to chocolates; however, the exposure of chocolate to temperature variations during transportation and/or storage can lead to changes in the polymorphic form of butter, with the appearance of a dull-white film on the chocolate surface, known as fat bloom. This study investigated the use of a portabl...

Multivariate Curve Resolution with Alternating Least Squares (MCR-ALS) was for the first time successfully used to evaluate an intricate photophysical behavior, where deprotonation on the electronic ground state (S0), intra and intermolecular proton transfer processes (ESPT and ESIPT) on the electronic excited state (S1) can simultaneously be prese...

Evaluation of electrochemical behavior of 5-type phosphodiesterase inhibitory drugs is of major concern since they have been added illegally as adulterants in dietary supplements. Then, for the first time, the solid-sate electrochemistry of sildenafil and tadalafil is described using voltammetry of immobilized microparticles (VIMP). An electrochemi...

Solid dispersions are an interesting option to improve the solubility of Class II (high permeability, low water solubility) drugs of the Biopharmaceutical Classification System without the use of organic solvents. However, structural changes (polymorphism) may be present in both active pharmaceutical ingredients (API) and excipients, which require...

This study evaluates the use of Fourier transform infrared spectroscopy with attenuated total reflectance (ATR/FTIR) in tandem with data driven soft independent modeling of class analogy (DD-SIMCA) to check authenticity and monitor virgin coconut oil adulteration. By using infrared spectra of pure samples and samples adulterated with canola, corn,...

This study aimed at developing control charts and classification models to investigate sugar and water addition in guava pulp applying near- and mid-infrared (NIR and MIR) spectroscopies and low-level data fusion to compare performance of them. The pulp was produced in a pilot plant (authentic samples) during the harvest season in São Paulo (Brazil...

Cotton threads forming a microfluidic device were used for the first time to conduct a fast and straightforward Turkevich synthesis of gold nanoparticles (AuNPs) using minute amounts of reagents. Spherical AuNPs were obtained with sizes that varied from 20 to 40 nm, according to the synthesis conditions. The cotton thread also acted as physical sup...

In this work, a methodology was proposed for detection and quantification of the four main roasted and ground coffee adulterants: coffee husks, roasted and powdered corn kernels, wood sticks, and soil, based on the combination of near-infrared hyperspectral imaging and multivariate curve resolution (MCR). By using this procedure, it was possible to...

The assessment of pesticide residue levels demands fast, low cost and easy-to-use procedures which are not found in conventional methods. In this work, SERS substrates based on the deposition of gold nanoparticles (GNPs) on common office paper were prepared using a wax printer. These substrates combined with Data Driven Soft Independent Modelling o...

Schizophrenia (SCZ) and bipolar disorder (BD) are severe mental disorders that pose important challenges for diagnosis by sharing common symptoms, such as delusions and hallucinations. The underlying pathophysiology of both disorders remains largely unknown, and the identification of biomarkers with potential to support diagnosis is highly desirabl...

Raman imaging spectroscopy is a relatively new technique that has raised interest in several areas of knowledge due to the possibility of evaluating the spatial distribution of compounds based on their spectra. This paper presents a brief history of the development of this important technique, a theoretical description of the Raman effect and the p...

Nanostructured lipid carriers (NLC) belong to youngest lipid-based nanocarrier class and they have gained increasing attention over the last ten years. NLCs are composed of a mixture of solid and liquid lipids, which solubilizes the active pharmaceutical ingredient, stabilized by a surfactant. The miscibility of the lipid excipients and structural...

This paper proposes the use of random forest for adulteration detection purposes, combining the random forest algorithm with the artificial generation of outliers from the authentic samples. This proposal was applied in two food adulteration studies: evening primrose oils using ATR-FTIR spectroscopy and ground nutmeg using NIR diffuse reflectance s...

A espectroscopia do infravermelho próximo é uma técnica muito utilizada para a análise de matéria orgânica do solo porém, os resultados podem variar devido a fatores externos, como a umidade, diminuindo assim a sua exatidão. Esse projeto visa a utilização de um método de transferência de calibração para amenizar a influência da umidade fazendo com...

The investigation of methodologies to obtain the metabolomic profile of blood serum from healthy individuals by LCMS/MS was performed by factorial planning and the number of molecular features as the system answer. Sample preparation, chromatographic and ionization source conditions were optimized, defining the best conditions to obtain the metabol...

Approximately 255 million people consume illicit drugs every year, among which 18 million use cocaine. A portion of this drug is represented by crack, but it is difficult to estimate the number of users since most are marginalized. However, there are no recognized efficacious pharmacotherapies for crack-cocaine dependence. Inflammation and infectio...

In the present work, Raman spectroscopy and chemometrics tools were explored as an analytical method to discriminate blue pen strokes on common office paper and bank check paper. The sample set was constituted of blue ballpoint pen inks available on local market and promotional pens as well. The samples were prepared to simulate an adulterated docu...

In formulations of nanostructured lipid carriers, lipid solid dispersions and self-emulsifying drug delivery systems, it is common that a solid or semi-solid lipid excipient is mixed with a liquid solvent or liquid lipid. Even when the excipients are visually miscible upon melting, they might have microscopic non-homogeneities which could lead to i...

Near-field plasmonic properties are fundamental for the various applications of metal nanoparticles. In this sense, a characterization of such properties is essential for a better understanding of the electromagnetic interactions probed by the materials. In this manuscript we discuss the possibility of using surface-enhanced Raman scattering (SERS)...

This study evaluates the use of Raman spectroscopy with a multivariate curve resolution–alternating least squares (MCR-ALS) analysis to monitor the adulteration and purity of coconut oil. Sunflower, soybean, canola, sesame, corn, castor bean, peanut, palm kernel, babassu, mineral, and Vaseline oils have been used as adulterants in this work. Contro...

Andiroba oil (Carapa guianensis Aubl) from the Amazonian region is one of the most important oils in popular medicine and cosmetic industry, has a high added value and is liable to adulteration with other cheaper or lower quality oils. Based on these facts, this work proposes a simple, fast, and accurate methodology to discriminate authentic andiro...

This work presents the use of near-infrared (NIR) spectroscopy as a fast and eco-friendly alternative to the conventional methods currently used for the quality control of cocoa beans. A key feature of this study was that the multivariate calibration models were built from the spectra of 81 samples of commercial cocoa beans from different producing...

Adenosine is a purine nucleoside that is present in all human cells and is essential for regulating certain physiological activities in tissues and organs. Since adenosine is considered to be a potential cancer biomarker in urine, its determination may be crucial for the early diagnosis and non-invasive monitoring of cancer. Herein, we present a la...

Chocolate quality depends on the type of cocoa and how its manufacture was conducted. In this work, the analysis of the volatile fraction of the principal steps - from cocoa to chocolate - was performed. For this purpose, unroasted nibs, liquor and chocolate samples from five different places were used, and the isolation was conducted by HS-SPME (h...

The quality control of pellets homogeneity cannot be assessed by conventional techniques and near infrared-chemical imaging combined with multivariate curve resolution with alternating least squares is an attractive alternative. In this study, composition and spatial distribution of pellets components were determined after assessment of experimenta...

The quality control of pellets homogeneity cannot be assessed by conventional techniques and near infrared-chemical imaging combined with multivariate curve resolution with alternating least squares is an attractive alternative. In this study, composition and spatial distribution of pellets components were determined after assessment of experimenta...

Single molecule surface-enhanced Raman Spectroscopy (SM-SERS) has the potential to revolutionize quantitative analysis at ultra-low concentrations (less than 1 nM). However, there are no established protocols to generalize the application of this technique in analytical chemistry. Here, a protocol for quantification at ultra-low concentrations usin...

Two methods of asphaltenes fractionation have been employed to facilitate the characterization of their respective subfractions. The methods are based on step-wise precipitation with different n-hexane/crude oil ratios, and on adsorption onto CaCO3. Three subfractions were produced for each method, being named of 3.5 V, 3.5–6 V, and 6–40 V (for the...

DIDACTIC EXPERIMENT OF CHEMOMETRICS FOR PHARMACEUTICAL PELLETS MAPPING USING NEAR-INFRARED SPECTROSCOPY AND MULTIVARIATE CURVE RESOLUTION WITH ALTERNATING LEAST SQUARES : A TUTORIAL, PART IV. The aim of this manuscript is to present a didactic experiment based on the combination of Near Infrared chemical imaging and Multivariate Curve Resolution f...

Na farinha de trigo (FT), proteínas insolúveis peculiares (glúten) causam doença celíaca em pessoas predispostas e seu consumo deve ser evitado pelos pacientes. A exigência legal da inscrição CONTÉM GLÚTEN nas embalagens desses alimentos, no Brasil, demanda testes rápidos e não destrutivos. Uma ferramenta útil nesse sentido é a espectroscopia no in...

Competitive adaptive reweighted sampling-partial least squares (CARS-PLS) and negative-ion mode electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI(-) FT-ICR MS) data were adopted to assess the total acid number (TAN) of crude oil distillation cuts. Two crude oil samples and 24 derivatives with TAN ranging from...

The short time of action and systemic toxicity of local anaesthetics limit their clinical application. Bupivacaine is the most frequently used local anaesthetic in surgical procedures worldwide. The discovery that its S(−) enantiomeric form is less toxic than the R(+) form led to the introduction of products with enantiomeric excess (S75:R25 bupiva...

One fundamental question in prey luring systems is to understand how visual signals are interpreted by the receiver. Predators lure prey by falsely imitating the signal of a model, or may exploit sensory preferences of the receivers, which search for rewarding signals. Crab spiders reflect ultraviolet (UV) light, ambush pollinators on flowers, and...

The industrial hydrogenation of soybean oil is well established. However, its control is carried out through time-consuming methods. The objective of this study was to evaluate the mid-infrared spectroscopy (FTIR-ATR) in tandem with support vector machines (SVM) in controlling the hydrogenation process. Models were constructed to predict the conten...

In this paper, we present the advantages and limitations of the coupling of a ring-oven-based preconcentration technique and surface-enhanced Raman spectroscopy (SERS). Three different methods to promote analyte adsorption on gold nanoparticles using crystal violet as a probe molecule were assessed. The results showed significant improvements in sa...

Pôster escolhido como um dos cinco melhores trabalhos apresentados no evento.

In this work a methodology was developed for quantification of the contents of petroleum-derived, hydroprocessed esters and fatty acids (HEFA) and farnesane jet fuels in binary and ternary mixtures using near infrared spectroscopy and multivariate calibration based on partial least squares (PLS) regression. The developed models are simpler, faster...

It is estimated nowadays that 40 to 70% of active pharmaceutical ingredients (API) are poorly water-soluble, which may result in erratic bioavailability. In order to overcome this problem, lipid-based formulations are becoming more widely used, since they improve in vitro solubility and in vivo bioavailability. Solid, semi-solid and liquid lipids,...

Background The objective of this study was to identify molecular alterations in the human blood serum related to bipolar disorder, using nuclear magnetic resonance (NMR) spectroscopy and chemometrics. Methods Metabolomic profiling, employing ¹H-NMR, ¹H-NMR T2-edited, and 2D-NMR spectroscopy and chemometrics of human blood serum samples from patien...

The emergence of antibiotics and their active metabolites in aquatic ecosystem has provoked the urgencies to develop sensitive and reliable sensors to monitor traces of antibiotics and metabolites in drinking water sources (i.e. surface water). Surface enhanced Raman scattering (SERS) technique, which is widely recognized as a high sensitivity tech...

In this work, Raman hyperspectral imaging, in conjunction with independent component analysis, was employed as an analytical methodology to detect an ammonium nitrate fuel oil (ANFO) explosive in banknotes after an ATM explosion experiment. The proposed methodology allows for the identification of the ANFO explosive without sample preparation or de...

Grape juice is rich in bioactive compounds that are known for beneficial effects, such as prevention of cancer and diabetes. The determination of the content of these compounds has been carried out following several protocols which generated toxic waste. In this context, infrared spectroscopy in near (NIR) and mid- (MIR) regions were applied for th...

J. Sep. Sci. 2017, 40, 2161–2169 DOI: 10.1002/jssc.201601444 The cover picture shows the use of chemometric models applied to data obtained by using ultra‐high performance chromatographic fingerprint of extracts of Chrysobalanus icaco Linnaeus (Chrysobalanaceae) leaves. C. icaco is commonly used in Brazilian's popular medicine due to its antidiabet...

Caseous Lymphadenitis (CLA) is a disease that affects animals, such as sheep, whose etiologic agent is Corynebacterium pseudotuberculosis. In sheep, it causes enormous damages, expressed through a reduction in milk, meat and wool production, or death of infected animals, and, also, difficulties in sterilizing infected animals habitats. Another prob...

Crack-cocaine abuse and dependence is a severe public health problem. Sometimes, the crack-cocaine smokers show behavioral changes and symptoms very similar to those observed for severe mental disorders, like schizophrenia. Although crack-cocaine use can easily be detected in smokers by urine or blood tests, after some time, cocaine biomarkers beco...

Raman spectroscopy and multivariate curve resolution with correlation constraint were used for the identification and quantification of biofuels and adulterants in petroleum diesel. Firstly, quantification of two biofuels present in petroleum diesel (biodiesel and hydrotreated esters and fatty acids (HEFA)) was performed. The developed models for b...

We investigated a strategy for the chemotaxonomy study of Chrysobalanus icaco Linnaeus (Chrysobalanaceae) based on ultra high performance liquid chromatography coupled with diode array detection fingerprint in combination with multivariate analysis. Two models using principal component analysis and partial least squares discriminant analysis were d...

Cancer is responsible for millions of deaths worldwide, but most base diseases may be cured if detected early. Screening tests may be used to identify early-stage malignant neoplasms. However, the major screening tool for prostate cancer, the prostate-specific antigen test, has unsuitable sensitivity. Since cancer cells may affect the pattern of co...

In this study, we introduce a simple protocol to manufacture disposable, 3D-printed microfluidic systems for sample preparation of petroleum. Such platform is produced with a consumer-grade 3D-printer, using fused deposition modeling. Successful incorporation of solid-phase extraction (SPE) to microchip was ensured by facile 3D element integration...

Resumo: < Combination of Comprehensive Two-Dimensional Gas Chromatography (GC×GC) and multivariate data processing was evaluated to model and predict the antifungal activity of essential oils of Menth sp. Metabolites secondary in leaves of various species and cultivars of Mentha were isolated by hydrodistillation and the antimycotic activity of the...

Phenolic compounds are important environmental contaminants due to their high toxicity and persistence in the environment. The use of enzyme-based electrochemical biosensors is a simple, sensitive and low-cost alternative for the determination of these pollutants in contaminated waters. However, in most cases, it is impossible to detect specific co...

Dielectrophoresis (DEP) is the electrokinetic movement of non-charged particles when they are subjected to a non-uniform electric field. This is a growing area of research, which can be used for trapping, concentrating and separating different particles. Some work has been reported with the intention of trapping metal particles to optimize the surf...

Near infrared (NIR) spectroscopy along with multivariate calibration was used for quality control of cashew apple and guava nectars. Total acidity, total sugars, soluble solids, pH, and ascorbic acid contents were analyzed by traditional wet chemical methodologies and NIR. The spectral data were preprocessed with multiplicative scatter correction,...