Brazilian Journal of Analytical Chemistry最新文献

{"title":"Development of an Air-assisted Dispersive Liquid-Liquid Microextraction Method as a Valuable Biomonitoring Tool for Exposure Assessment of Phthalates","authors":"Bruno Rocha, M. Gallimberti, Marília Souza, João Ximenez, A. Martino-Andrade, José Domingo, F. Barbosa Jr.","doi":"10.30744/brjac.2179-3425.ar-91-2023","DOIUrl":"https://doi.org/10.30744/brjac.2179-3425.ar-91-2023","url":null,"abstract":"In recent years, the number of epidemiological studies on phthalates that can inform and help update health risk assessments has grown rapidly. Developing reliable and rapid analytical methods for determining phthalate monoesters (m-PAEs) is an important biomonitoring tool for assessing exposure. In this study, a fast and sensitive method was developed to determine 15 m-PAEs in human urine samples as effective biomarkers for exposure assessment. Air-assisted dispersive liquid-liquid microextraction and liquid chromatography coupled to mass spectrometry were used. In order to determine the optimal conditions and model the variables influencing the extraction efficiency, a central composite rotatable design coupled with response surface methodology was used. Under the optimized conditions, the method achieved good linearities (R > 0.99), satisfactory intra- and inter-day accuracies (97–111%), and intra- and inter-day precision (RSD < 14%). The proposed procedure allowed the detection of the m-PAEs with limit of detection values between 0.02 and 0.10 ng mL-1, which makes the method sensitive and appropriate for assessing internal exposure to phthalates. The applicability of the proposed procedure was evaluated by screening fifty children’s urine from Brazil. High detection frequencies and urinary concentrations of several m-PAEs associated with using personal care products and diet were found.","PeriodicalId":9115,"journal":{"name":"Brazilian Journal of Analytical Chemistry","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2023-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138999978","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design of Experiments (DoE) Application in Two Cases of Study in Pharmaceutical Industries","authors":"Romero Souza, Luiz Bonamichi, Edenir Pereira-Filho","doi":"10.30744/brjac.2179-3425.ar-56-2023","DOIUrl":"https://doi.org/10.30744/brjac.2179-3425.ar-56-2023","url":null,"abstract":"This study illustrates the practical application of Design of Experiments (DoE) in two real-life scenarios within the pharmaceutical industry. The first case involved optimizing a chromatographic method for the determination of multiple analytes and their degradation products. The primary variable of interest was gradient time, and the most favorable outcomes were achieved at a pH value of 2. In the second case, we conducted a shelf-life study for a veterinary product, revealing that the vial filling variable exerted a statistically significant impact (p-value < 0.05). The incorporation of DoE in both cases played an important role in ensuring the attainment of dependable and statistically validated results.","PeriodicalId":9115,"journal":{"name":"Brazilian Journal of Analytical Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136037967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Professor Manuel Miró, a researcher with an extensive and prestigious academic career, kindly spoke to BrJAC","authors":"Manuel Miró","doi":"10.30744/brjac.2179-3425.interview.mmiro","DOIUrl":"https://doi.org/10.30744/brjac.2179-3425.interview.mmiro","url":null,"abstract":"Manuel Miró received his M.Sc. (1998) and Ph.D. (2002) in Chemistry from the University of the Balearic Islands, Spain. He has conducted post-doctoral research in several universities, including the Technical University of Berlin, Technical University of Denmark and University of Natural Resources and Applied Life Sciences. He is currently Full Professor in Analytical Chemistry at the University of the Balearic Islands (since September 2017); Guest Professor at Charles University (Czech Republic) (since 2014); and member of the IUPAC Chemistry and Environment Division (Subcommittee on Chemical and Biophysical Processes in the Environment). He has completed and consolidated four teaching periods (each of 5 years) and three research periods (each of 6 years). Dr. Miró is the Reviews Editor of the journal Analytica Chimica Acta (Elsevier, IF: 6.91, the second highest IF across scientific journals for general analytical chemistry) and Associate Editor of the Encyclopedia of Analytical Science, 3rd Edition, Elsevier, positions that he has held since 2007 and 2016, respectively. His publication record shows over 220 refereed publications, including 14 book chapters and a foreword, with an h-index of 42 and over 5600 citations. He has published 24 articles in the prestigious journal ‘Analytical Chemistry’ from the American Chemical Society and is the corresponding author of 110 articles. Dr. Miró has delivered 70 oral presentations (60 as plenary, keynote, or invited lecturer) at international conferences on analytical chemistry, sample preparation, nanotechnology, environmental chemistry, and automation based on flow methodology. He has also presented over 180 poster communications in international conferences and symposiums. He has supervised 10 Ph.D. students in national and international universities (Technical University of Denmark, Mahidol University and Chiang Mai University in Thailand, University of the Balearic Islands in Spain, and Federal University of Bahia in Brazil). He has been actively engaged in 34 national and international research projects (e.g., University of Melbourne in Australia and Charles University in Czech Republic), including 16 as the Principal Investigator. Dr. Miró’s research interests are focused on the development of on-line sample processing strategies for isolation and/or preconcentration of trace levels of environmental pollutants, exploiting 3D printing in the generation of various flow injections, including 3D-printed µFIA and Lab-on-a-Valve mesofluidic platforms, in conjunction with modern analytical instrumentation.","PeriodicalId":9115,"journal":{"name":"Brazilian Journal of Analytical Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134944705","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"How has the pandemic accelerated the transformation of Analytical Chemistry education from Generation Z to Alpha?","authors":"Mariela Pistón","doi":"10.30744/brjac.2179-3425.point-of-view-mpiston.n41","DOIUrl":"https://doi.org/10.30744/brjac.2179-3425.point-of-view-mpiston.n41","url":null,"abstract":"Teaching Generation Z (Zs or Centennials) has become a great challenge since students arrived at the university classrooms meeting professors of different generations, from Baby Boomers, through Generations X and Y (Millennials) and even young assistants of the same generation. This became an interesting challenge to tackle, and we thought this transition was going to take a while. But suddenly, in the year 2020, a pandemic began, something totally unexpected that left us in shock, and without a reaction time for transitions, those of us who teach experimental sciences in universities were forced overnight by the most incredible challenges to improve our creativity to maintain the quality of teaching of Analytical Chemistry. There was no time to identify with any generation… suddenly we were all Zs (the digital generation) and additionally began to know about Generation Alpha. From my point of view, as a woman of Generation X (mavericks seeking success), and as a Professor of Analytical Chemistry, having started as an assistant in classes of this discipline in 1996, I would like to share my experience on how the pandemic irreversibly accelerated the use of digital tools, not to get closer to Generation Z, but without realizing it, reaching a transition to Generation Alpha (those born in the 2010s), despite the fact that they have not yet arrived at university. Generation X and earlier were used to face-to-face classes, to the university coexistence of many hours in the classrooms and in the libraries. Then we began to think about virtual classes, digital platforms, enabling work to be done with the help of internet resources, but suddenly... chaos! In 2020, there were worldwide restrictions on face-to-face access to university classrooms, and now what do we do? Thinking about Analytical Chemistry, we could teach the theoretical content online, but what about the experiments in the laboratory? The use of instruments? Exams and evaluations? It was real chaos; teachers experienced anxiety and higher levels of burnout. Communications via cell phones and messages became the form of contact and the number of e-mails skyrocketed. Teleworking, with the family around, work without a fixed schedule and an infringement of privacy, became the norm. Those were difficult times; those teachers closest to Generation Z adapted more quickly; for those of the Baby Boomer generation the situation accelerated their retirement processes; and for those of us from Generation X or Y... we could be considered survivors. Once the pandemic ended, at least in our university, we waited with great enthusiasm for the return to classrooms expecting to see them full of students; however, we went through another shock: the theoretical classrooms were empty. During the pandemic, a lot of recorded material was generated through digital platforms that the students themselves later requested to the authorities to be kept online, so they stopped attending theoretical classes. Now they ","PeriodicalId":9115,"journal":{"name":"Brazilian Journal of Analytical Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134944709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Metallomics as an Essential Analytical Tool for the Development of Potential Metallodrugs","authors":"Ignacio Machado","doi":"10.30744/brjac.2179-3425.letter-imachado.n41","DOIUrl":"https://doi.org/10.30744/brjac.2179-3425.letter-imachado.n41","url":null,"abstract":"Metallomics is an emerging area of the omics disciplines that has grown enormously since its conception as an academic discipline in 2004. This discipline integrates research related to biometals, along with other disciplines such as genomics, proteomics, metabolomics, and bioinorganic chemistry. It is defined as the study of the metallome, the interactions and functional connections of metal ions or species with genes, proteins, metabolites, and other biomolecules in biological systems. The study of the metallome of a species can provide information on the distribution of an element between cellular compartments, on the coordination environment in which a biomolecule is incorporated, or on the concentration of individual metal species present. In this regard, it plays a very important role in providing integrated information that connects metallomics with other omics disciplines.1,2 The term ‘metallomics’ was pronounced for the first time in June 2002 during the Tokushima Seminar on Chemical Engineering held in Tokushima, Japan, where the development of this new omics discipline was suggested, which was closely influenced by the progress of Analytical Atomic Spectrometry, in particular by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) and Inductively Coupled Plasma Atomic Emission Spectrometry (ICP-AES). Since the mid-1970s, ICP-MS and ICP-AES techniques have been positioned as highly sensitive analytical tools with excellent possibilities for simultaneous quantification of multiple elements. Nowadays, it is possible to carry out analyses of basically all the elements in any type of sample using one of these two techniques. Likewise, the use of several other techniques for metallomic studies has been reported, such as Electrothermal Atomic Absorption Spectrometry (ETAAS), Microwave Plasma Atomic Emission Spectrometry (MP-AES), Laser Induced Plasma Spectroscopy (LIBS), and Energy Dispersive X-Ray Fluorescence Spectrometry (EDXRF), among others.2 A very useful bioanalytical study, within the field of metallomics, is the cellular uptake assay of potential metallodrugs. Using an adequate analytical technique, the metallic center of a given metallodrug can be monitored, and thus the fraction capable of entering a certain type of cell can be evaluated. Likewise, the distribution at the subcellular level and the association of the studied metallodrug with biomacromolecules of interest may be studied. In this context, our research group has been working on the optimization and validation of different bioanalytical methods for monitoring potential metallodrugs with activity against Trypanosoma cruzi, a protozoan parasite that causes Chagas disease, which is a pressing health problem in high-poverty areas of Latin America.3 A large number of metallic compounds with anti-Trypanosoma cruzi activity have been synthesized by our group, using as a strategy the coordination of metal ions or organometallic centers of pharmacological importance with bioact","PeriodicalId":9115,"journal":{"name":"Brazilian Journal of Analytical Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134944706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"What is the Best Definition for (Bio)Analytical Chemistry?","authors":"Ignacio Machado","doi":"10.30744/brjac.2179-3425.editorial.imachado.n41","DOIUrl":"https://doi.org/10.30744/brjac.2179-3425.editorial.imachado.n41","url":null,"abstract":"One of the simplest definitions for analytical chemistry is “the branch of chemistry concerned with analysis.”1 But what does \"analysis\" really mean? In the past it was synonymous for decomposition. However, with the rise of new technologies, it is no longer necessary to destroy samples to know their composition. Therefore, the current meaning of analysis refers to the identification and quantification of different analytes without the need for decomposition. However, analytical chemists do not merely provide results; they also develop strategies to measure different chemical properties. Furthermore, they spend an enormous amount of time interpreting the obtained data. Thus, considering the vast variety of works involving analytical chemistry, a more comprehensive definition of the discipline is required. Analytical chemistry was defined in the second half of the 20th century as “the chemical discipline that gains information on the chemical composition and structure of substances, particularly on the type of species, their amount, possible temporal and spatial changes, and structural relationships between the constituents.”2 In 1993, the Working Party on Analytical Chemistry (WPAC) of the Federation of European Chemical Societies (FECS) defined analytical chemistry as “a scientific discipline that develops and applies methods, instruments, and strategies to obtain information on the composition and nature of matter in space and time,” indicating that the development of methods and instruments is a central part of this science.3 However, some analytical chemists consider that this sort of definition does not entirely reflect the identity and wide scope of analytical chemistry. In the year 2000, Professor Miguel Valcárcel proposed a more comprehensive definition for analytical chemistry as “a metrological science that develops, optimizes and applies material, methodological and strategic tools of widely variable nature which materialize in measurement processes intended to derive quality (bio)chemical information of both partial [presence or concentration of bio(chemical) analyte species] and global nature on materials or systems of widely variable nature (chemical, biochemical and biological) in space and time in order to solve scientific, technical and social problems.”4 This constitutes a very encompassing definition because it includes more complete information that contributes to a deeper characterization and understanding of the discipline, while highlighting the different capabilities and approaches as well as some of the challenges. So, many definitions can be found in the literature. The truth is that while some definitions express essential aspects of (bio)analytical chemistry and the analytical work, others characterize it in a very concise way. Furthermore, while some authors consider it to be a branch of chemistry independent of other chemical disciplines, others classify it as an autonomous science called analytical sciences.4 The im","PeriodicalId":9115,"journal":{"name":"Brazilian Journal of Analytical Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134944708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determination of Abamectin in Soybean Roots by Liquid Chromatography Coupled to Tandem Mass Spectrometry","authors":"Eliezer de Oliveira, Bianca da Silva, Carla Bottoli","doi":"10.30744/brjac.2179-3425.ar-46-2023","DOIUrl":"https://doi.org/10.30744/brjac.2179-3425.ar-46-2023","url":null,"abstract":"Abamectin has been used by seed treatment to control plant-parasitic nematodes in Brazil. In this work, foliar spray was performed as an alternative application method and a LC-MS/MS method employing QuEChERS for sample preparation was developed for the analysis of abamectin in soybean roots. For this, abamectin was applied on the leaves and the translocation of this pesticide from leaves to roots was evaluated. The method was validated and presented adequate selectivity. Matrix-matched was used as an approach to calibration. Good linearity of the analytical curve was obtained over the studied range of concentrations from 0.10 to 1.0 mg kg-1, with a determination coefficient of 0.995. The limit of detection was 0.05 mg kg-1, and the limit of quantification was 0.10 mg kg-1. Recoveries were in the range of 99 to 106% and RSD < 20%. Finally, root samples after foliar spray were analyzed, and abamectin was not detected.","PeriodicalId":9115,"journal":{"name":"Brazilian Journal of Analytical Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135107106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determination of basic nitrogen content in diesel oil: A miniaturized method by digital image-based colorimetry in a portable device","authors":"Gabrielle Iop, Alice Holkem, Andres de Souza, Edson Muller, Juliano Barin, Paola Mello","doi":"10.30744/brjac.2179-3425.ar-47-2023","DOIUrl":"https://doi.org/10.30744/brjac.2179-3425.ar-47-2023","url":null,"abstract":"A miniaturized method using a portable device with digital image acquisition and PhotoMetrix PRO app data treatment was developed for the determination of basic nitrogen content in diesel oil. The method was based on the colorimetric titration described in the UOP 269-10 standard protocol. A homemade 3D-printed chamber with controlled light intensity equipped with an USB camera was used for image acquisition after an acid-base titration reaction, carried out in a miniaturized device. After mixing reagents and diesel oil, the images were obtained and converted into RGB (red, green, and blue) histograms, and a partial least squares (PLS) multivariate calibration model was constructed. Parameters of the regression model were evaluated, by the coefficient of determination (R2), the root mean squared error of calibration (RMSEC), the root mean squared error of cross-validation (RMSECV), and the root mean squared error of prediction (RMSEP). Some conditions for the acid-base titration were optimized, such as the concentration of the indicator (68.0 to 272 µmol L-1) and the titrating (HClO4, 0.179 to 1.79 mmol L-1), as well as the volume of diesel oil. With 60 µL of 2.54 mmol L-1 indicator solution, 20 µL of 20 mmol L-1 HClO4 as titrating and using 50 to 1000 µL of diesel oil, optimal conditions were obtained for calibration (RMSEP of 0.377 mg kg-1, RMSECV of 0.307 mg kg-1 with 4 factors). It is important to mention that no differences were observed (p < 0.05) when comparing reference values with the results by the proposed protocol. This proved to be advantageous in relation to the methods described in the UOP 269-10 standard since it was possible to reduce the consumption of reagents and waste generation, in agreement with green analytical chemistry. In addition, this alternative protocol combines simplicity and speed to obtain results with good accuracy, precision and suitable limit of quantification (1 mg kg-1) using a miniaturized system.","PeriodicalId":9115,"journal":{"name":"Brazilian Journal of Analytical Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135202704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ultrasound-assisted Extraction Method for Element Determination in Lignocellulosic Biomass","authors":"Karen Giacobe, Débora de Almeida, Samuel Waechter, Fabio Duarte, Cezar Bizzi","doi":"10.30744/brjac.2179-3425.ar-51-2023","DOIUrl":"https://doi.org/10.30744/brjac.2179-3425.ar-51-2023","url":null,"abstract":"In this work, a sample preparation method based on ultrasound-assisted extraction (UAE) for the determination of Al, Ba, Ca, Fe, K, Mg, Mn, Na, P, Sr, and Zn in lignocellulosic biomasses (sugarcane bagasse, eucalyptus wood residues, and pine wood residues) was evaluated. Reference values were achieved following the EN ISO 16967, which was based on a microwave-assisted wet digestion sample preparation method for further element determination by inductively coupled plasma optical emission spectrometry (ICP OES). The optimizations for the proposed UAE method were performed using 250 mg of sugarcane bagasse sample, where the ultrasonic bath frequency (25, 35, 37, 45, 80, and 130 kHz), and acoustic amplitude (50, 70 and 100%) were evaluated. After selecting the most efficient extractant solvent (20 mL of 1 mol L-1 of H2O2, HNO3, H2SO4, H2O, or CH2O2), the extraction temperature (20, 50, or 70 ºC) and time (15, 30, or 40 min) were evaluated. The most efficient extraction condition using the UAE method employed 45 kHz (70% amplitude), 20 mL of 1 mol L-1 of H2SO4, and 50 °C for 30 min. The optimized UAE was used for extraction and subsequent element determination in residues of pine wood and eucalyptus wood. Although poor recoveries were observed for Al, Ba, and Fe (lower than 75%), the results for Ca, K, Mg, Mn, Na, P, Sr, and Zn were in agreement (Student t-test, 95% confidence level) with those obtained by EN ISO 16967. Therefore, the proposed UAE method proved to be efficient for the determination of most of the evaluated elements in lignocellulosic biomasses with different matrix complexity, employing milder extraction conditions and diluted reagents.","PeriodicalId":9115,"journal":{"name":"Brazilian Journal of Analytical Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136023264","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Determination of Ethanol Levels in Facial Freshener Using the NIR Spectroscopy and Chemometric Method","authors":"Wahyu Febriyanti, Nia Kristiningrum, Lestyo Wulandari","doi":"10.30744/brjac.2179-3425.ar-96-2022","DOIUrl":"https://doi.org/10.30744/brjac.2179-3425.ar-96-2022","url":null,"abstract":"A facial freshener, also known as toner, is a cosmetic product that is commonly used to invigorate the face after a busy day. Ethanol serves as a key component in toner, serving multiple purposes such as being a solvent, preservative, and antimicrobial agent. However, it's important to note that toner formulated for normal skin types typically contain ethanol in small concentrations, adhering to a limit of not more than 10%. Therefore, this study aims to determine ethanol levels in toner using the NIR spectroscopy and chemometric techniques. The NIR spectra of the simulated samples were correlated with ethanol concentration using chemometric calibration model. The calibration models used were partial least square (PLS), principal component regression (PCR), and support vector regression (SVR). The calibration model was validated by leave one out cross validation (LOOCV) as well as the external validation, and the precision and accuracy of the method was evaluated. Among the calibration models, the PLS model exhibited the best performance, yielding an impressive R2 0.9976; with an RMSEC value of 0.4364 and RMSECV value of 0.4704. The internal validation yield R2 value more than 0.99 and RMSE of less than 0,4198. Furthermore, external validation showed the R2 and RMSEP value of 0.989 and 0.920 respectively. The %recovery and RSD value were 101.2% and 0.129%. Comparing ethanol measurements obtained through the NIR chemometric method with those obtained using gas chromatography as the reference method, no significant difference was observed at a 95% confidence levels, as indicated by a significance value of 0.231.","PeriodicalId":9115,"journal":{"name":"Brazilian Journal of Analytical Chemistry","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136023265","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}