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Made available in DSpace on 2019-10-06T17:18:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-01-01 In this study, 1H NMR spectroscopy was used to classify samples of beer, considering three categories (Ambev, Heineken, and Grupo Petrópolis), employing chemometric methods: principal component analysis (PCA), partial least squares discriminant analysis (PLS-DA), and soft independent modeling of class analogies (SIMCA). The full NMR spectra were evaluated, although only the aliphatic region (0–3 ppm) was used for multivariate analysis, since it provided superior results, compared to the use of other regions or the full spectrum. It was necessary to use an alignment procedure to eliminate small deviations in the chemical shifts caused by variations of pH and intermolecular interactions. Organic acids (lactic, acetic, and succinic acids) were the chemical compounds most susceptible to these variations. In the PCA, the first two components explained 82.1% of the variability of the dataset, while PLS-DA and SIMCA both provided accuracy higher than 92% in the prediction sets. Institute of Chemistry São Paulo State University (UNESP), Rua Prof. Francisco Degni 55 São Paulo Federal Institute of Education Science and Technology (IFSP), Rua Stefano D’avassi 625 Institute of Chemistry São Paulo State University (UNESP), Rua Prof. Francisco Degni 55

Made available in DSpace on 2019-10-06T17:04:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-06-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Development and application of a new, simple, inexpensive, and eco-friendly method is presented for the quantification of bumetanide in human urine samples for the detection of doping in sports. The method involves the use of a paper platform and digital image detection and is based on the reaction between bumetanide, p-dimethylaminocinnamaldehyde (p-DAC), and HCl in a methanolic medium, yielding a colored compound in a delimited area on a qualitative filter paper. The concentrations of p-DAC and HCl were optimized by a chemometric experimental design. After the addition of the reagents to the paper, digital images were obtained by scanning in a multifunctional printer and analyzed using the RGB pattern. The linear bumetanide concentration range was 6.90 × 10 −5 –1.37 × 10 −3 mol L −1 with R 2 = 0.993 and the limits of detection (LOD) and quantification (LOQ) were 3.60 × 10 −4 and 1.09 × 10 −4 mol L −1 , respectively. A SPE clean-up step for the samples were required to eliminate the interference of urinary urea. The recoveries obtained varied from 94% to 105%, indicating the absence of significant matrix effects or interferences in urine samples after clean-up step. The proposed method was successfully applied to the analysis of bumetanide in human urine samples. Instituto de Química Universidade Estadual Paulista “Júlio de Mesquita Filho” UNESP, R. Prof. Francisco Degni 55, P.O. Box 355 Instituto de Química Universidade Estadual Paulista “Júlio de Mesquita Filho” UNESP, R. Prof. Francisco Degni 55, P.O. Box 355 CAPES: 001 FAPESP: 2015/21733-1

Made available in DSpace on 2020-12-12T02:09:36Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-06-03 In this study, the direct analysis of doping agents in urine samples with no sample preparation by a modified paper spray mass spectrometry (PS-MS) methodology has been demonstrated for the first time. We have described a paper surface treatment with trichloromethylsilane using a gas-phase reaction to increase the ionization of target compounds. This approach was applied for the analysis of two classes of banned substances in urine samples: anabolic agents (trenbolone and clenbuterol) and diuretics (furosemide and hydrochlorothiazide). Under optimized conditions, the developed methods presented satisfactory repeatability, and an analysis of variance showed linearity without lack-of-fit. Highly sensitive detections as low as sub-nanogram per milliliter levels, which is below the minimum required performance levels proposed by the World Anti-Doping Agency, have been reached using the hydrophobic PS-MS analysis without any preconcentration and cleanup step. Department of Chemistry and Biochemistry Ohio State University, 100 West 18th Avenue Institute of Chemistry Department of Analytical Chemistry São Paulo State University (UNESP), Rua Professor Francisco Degni 55 ,P.O. Box 355 Institute of Chemistry Department of Analytical Chemistry São Paulo State University (UNESP), Rua Professor Francisco Degni 55 ,P.O. Box 355

Made available in DSpace on 2020-12-12T02:33:14Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-06-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Brazil is still the world's largest producer and exporter of coffee. In order to maximize profits, some producers may add lower cost materials (such as corn, barley, or even coffee husks) to commercial coffee. In view of the growing market for coffee products and the importance of coffee for the Brazilian economy, it is necessary to have a rapid, simple, and reliable methodology to identify and quantify coffee adulterants. NMR has proved to be a versatile and robust tool for the identification of adulterants in foods and beverages. Here, we explore the versatility of 1H NMR assisted with chemometric tools, avoiding laborious data analysis, for the quantification of coffee adulteration. Six different adulterants were considered: barley, corn, coffee husks, soybean, rice, and wheat. The NMR-based methodology described here provided satisfactory LOD values (0.31–0.86%) for adulterants in medium and dark roast coffees. The statistical techniques PCA and SIMCA were employed for pattern recognition and the identification of pure and adulterated samples. Use of the SIMCA model enabled 100% correct classification for both training and prediction sets, ensuring the accuracy, traceability, and reliability of the results. Instituto de Química UNESP - Universidade Estadual Paulista, Rua Prof. Francisco Degni 55, C.P. 355 Instituto Latino-americano de Ciências da Vida e da Natureza UNILA - Universidade Federal da Interação Latino-americana, Av. Tancredo Neves 6731, C.P. 2044 Instituto de Química UNESP - Universidade Estadual Paulista, Rua Prof. Francisco Degni 55, C.P. 355 CNPq: #141365/2016-1 FAPESP: #2016/14773-0

1H NMR spectroscopy combined with chemometrics was employed to discriminate lager beer samples from two different classes, according to their style and information provided on the label. Partial replacement of barley malt by adjuncts is a common practice adopted by large breweries, which can lead to a decrease in diastatic power, requiring the use of exogenous enzymes. For this reason, small variations in the spectral profile can occur in the carbohydrates region. Many studies have focused on differentiating beers according to type and brewing process. However, there have no studies concerning the discrimination of beers of the same type that differ only in style, using 1H NMR spectroscopy. In this study PCA (first three components explained 81.5% of the dataset variability), PLS-DA and SIMCA models proved to be powerful tool with predict power higher than 90% for distinguishing lager beers based on the raw materials employed in the brewing process.

Submitted by Guilherme Lemeszenski (guilherme@nead.unesp.br) on 2013-08-22T18:49:12Z No. of bitstreams: 1 S0100-46702003000100005.pdf: 207052 bytes, checksum: 9f60aacb2f1e62b19acf1f361e8732c5 (MD5) Made available in DSpace on 2013-08-22T18:49:12Z (GMT). No. of bitstreams: 1 S0100-46702003000100005.pdf: 207052 bytes, checksum: 9f60aacb2f1e62b19acf1f361e8732c5 (MD5) Previous issue date: 2003-01-01 Made available in DSpace on 2013-09-30T19:09:22Z (GMT). No. of bitstreams: 2 S0100-46702003000100005.pdf: 207052 bytes, checksum: 9f60aacb2f1e62b19acf1f361e8732c5 (MD5) S0100-46702003000100005.pdf.txt: 17095 bytes, checksum: f300bef6d0670d982afadb2704fb6bf6 (MD5) Previous issue date: 2003-01-01 Submitted by Vitor Silverio Rodrigues (vitorsrodrigues@reitoria.unesp.br) on 2014-05-20T14:19:41Z No. of bitstreams: 2 S0100-46702003000100005.pdf: 207052 bytes, checksum: 9f60aacb2f1e62b19acf1f361e8732c5 (MD5) S0100-46702003000100005.pdf.txt: 17095 bytes, checksum: f300bef6d0670d982afadb2704fb6bf6 (MD5) Made available in DSpace on 2014-05-20T14:19:41Z (GMT). No. of bitstreams: 2 S0100-46702003000100005.pdf: 207052 bytes, checksum: 9f60aacb2f1e62b19acf1f361e8732c5 (MD5) S0100-46702003000100005.pdf.txt: 17095 bytes, checksum: f300bef6d0670d982afadb2704fb6bf6 (MD5) Previous issue date: 2003-01-01 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação para o Desenvolvimento da UNESP (FUNDUNESP) Um método potenciométrico simples, preciso, rápido e de baixo custo foi proposto para a determinação de captopril na forma pura e em formulações farmacêuticas. O captopril presente em comprimidos em uma quantidade conhecida foi potenciometricamente titulado em meio aquoso com um titulador automático, empregando-se como titulante uma solução aquosa de NaOH e um eletrodo combinado de vidro sensível a pH. Interferências não foram observadas na presença de componentes comumente encontrados nos comprimidos, tais como, lactose, celulose microcristalina, croscarmelose sódica, amido e estearato de magnésio. Os resultados analíticos obtidos a partir da aplicação do método proposto estão em muito boa concordância com aqueles obtidos pelo método oficial descrito na Farmacopéia Americana. O recobrimento obtido para o captopril a partir de um estudo realizado com várias formulações farmacêuticas variou de 98.0 a 102.0%. A simple, precise, rapid and low-cost potentiometric method for captopril determination in pure form and in pharmaceutical preparations is proposed. Captopril present in tablets containing known quantity of drug was potentiometrically titrated in aqueous solution with NaOH using a glass pH electrode, coupled to an autotitrator. No interferences were observed in the presence of common components of the tablets as lactose, microcrystalline cellulose, croscarmellose sodium, starch and magnesium stearate. The analytical results obtained by applying the proposed method compared very favorably with those obtained by the United States Pharmacopoeia Standard procedure. Recovery of captopril from various tablet dosage formulations range from 98.0 to 102.0%. UNESP Instituto de Química Departamento de Química Analítica UNESP Instituto de Química Departamento de Química Orgânica UNESP Instituto de Química Departamento de Química Analítica UNESP Instituto de Química Departamento de Química Orgânica

A clean environmental spectrophotometric method for the analysis of nitrite using a new diazotizing reagent is reported. The proposed method is based on diazotization-coupling reaction between dapsone, nitrite and (naphthyl)ethylenediamine (NED) in phosphoric acid medium at room temperature. Experimental design methodologies were used to optimize the measurement conditions. The spectrophotometric measurements were carried out at 545 nm and the linear range obtained was 5.0 x 10-3 mg.L-1 – 0.5 mg.L-1, with detection and quantification limits of 0.99 x 10-3 mg.L-1 e 3.31 x 10-3 mg.L-1, respectively. The proposed method was applied successfully to the analysis of nitrite in sausages and the results obtained by the proposed method were in good agreement with those obtained using the official method.

A simple, rapid, accurate and inexpensive spectrophotometric method for the determination of tetracycline and doxycycline has been developed. The method is based on the reaction between these drugs and chloramine-T in alkaline medium producing red color products with absorbance maximum at the Λ = 535 and 525 nm for the tetracycline and doxycycline, respectively. The best conditions for the reactions have been found using multivariate method. Beer´s law is obeyed in a concentration ranges 1.03 x 10-5 to 3.61 x 10-4 mol L-1 and 1.75 x 10-5 to 3.48 x 10-4 mol L-1 for the tetracycline and doxycycline, respectively. The quantification limits were 5.63 x 10-6 mol L-1 and 7.12 x 10-7 mol L-1 for the tetracycline and doxycycline, respectively. The proposed method was successfully applied to the determination of these drugs in pharmaceutical formulations and the results obtained were in good agreement with those obtained by the comparative method at the 95% confidence level.Um método espectrofotométrico simples, rápido, exato e barato foi desenvolvido para a determinação de tetraciclina e doxiciclina. O método é baseado na reação entre estas drogas e cloramina-T em meio alcalino produzindo produtos de cor vermelha com absorbância máxima em 535 e 525 nm para a tetraciclina e doxiciclina, respectivamente. As melhores condições para as reações foram encontradas utilizando métodos multivariados. A lei de Beer é obedecida no intervalo de concentração de 1,03 x 10-5 a 3,61 x 10-4 mol L-1 e 1,75 x 10-5 a 3,48 x 10-4 mol L-1 para a tetraciclina e doxiciclina, respectivamente. Os limites de quantificação foram 5,63 x 10-6 mol L-1 e 7,12 x 10-7 mol L-1 para a tetraciclina e doxiciclina, respectivamente. O método proposto foi aplicado com êxito na determinação destas drogas em formulações farmacêuticas e os resultados obtidos estão de acordo com os obtido pelo método comparativo em 95% de confiança.

Made available in DSpace on 2018-12-11T17:34:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-01-02 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) In this paper, we describe a validated paper-based microfluidic analytical device for the simultaneous quantification of two important biomarkers of renal function in urine. This paper platform provides an inexpensive, simple, and easy to use colorimetric method for the quantification of creatinine (CRN) and uric acid (UA) in urine samples. The microfluidic paper-based analytical device (μPAD) consists of a main channel with three identical arms, each containing a circular testing zone and a circular uptake zone. Creatinine detection is based on the Jaffé reaction, in which CRN reacts with picrate to form an orange-red product. Uric acid quantification is based on the reduction of Fe3+ to Fe2+ by UA, which is detected in a colorimetric reaction using 1,10-phenanthroline. Under optimum conditions, obtained through chemometrics, the concentrations of the analytes showed good linear correlations with the effective intensities, and the method presented satisfactory repeatability. The limits of detection and the linear ranges, respectively, were 15.7 mg L−1 and 50–600 mg L−1 for CRN and 16.5 mg L−1 and 50–500 mg L−1 for UA. There were no statistically significant differences between the results obtained using the μPAD and a chromatographic comparative method (Student's t-test at 95% confidence level). Instituto de Química Universidade Estadual Paulista “Julio de Mesquita Filho”- UNESP, R. Prof. Francisco Degni 55, P.O. Box 355 Instituto de Química de São Carlos Universidade de São Paulo, Av. Trabalhador São-carlense, 400 Instituto de Química Universidade Estadual Paulista “Julio de Mesquita Filho”- UNESP, R. Prof. Francisco Degni 55, P.O. Box 355 CNPq: 132646/2014-5 CAPES: 2014/17749-7 FAPESP: 2015/21733-1 CNPq: 308788/2015-0

Anabolic steroids are synthetic hormone derivatives of testosterone, a masculine sex hormone. Their main effects include greater muscle size, physical strength, and resistance. The need for safe and reliable quality control of products and/or raw materials in the pharmaceutical industry makes analyses of active ingredients and other constituents of drug formulations extremely important for the manufacturers as well as users of these products. In this work, we propose the use of 1H NMR spectroscopy to analyze formulations containing anabolic steroids. Six types of anabolic steroids were studied (testosterone propionate, methyltestosterone, acetate methenolone, oxandrolone, nandrolone decanoate, and stanozolol), with analysis of 16 samples of anabolic drugs that are used in injectable, tablet, and capsule forms. The 1H NMR spectroscopic measurements were performed using a 600 MHz spectrometer, with deuterated chloroform (CDCl3) containing 0.03% TMS as the solvent. Of the 16 samples analyzed, four did not show the presence of the active principle stated on the label. For quantitative analysis, dimethyl sulfone (DMSO2) was used as an internal reference standard. All the analytical curves were obtained for concentration ranges of 1.0–16.0 mg mL−1. The limits of detection and quantification varied in the ranges 0.18–0.61 and 1.30–2.19 mg mL−1, respectively. The intra-day and inter-day precision RSD values were in the ranges 1.86–4.22% and 2.17–4.75%, respectively. The recovery values ranged from 95.2 to 104.0%. The spectroscopic results statistically agreed with those obtained by reference methods (HPLC).

Made available in DSpace on 2019-10-06T17:07:56Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-08-15 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) In this paper, we describe a novel carbon dot (CD)synthesized from citric acid and tyramine using a one-step microwave heating route. Under UV irradiation, the CD displayed blue emission that was quenched in the presence of H2O2 and peroxidase. This property was used to quantify glucose in biological samples, using a standard additions procedure employing a paper platform and the H2O2 formed in the enzymatic reaction with glucose oxidase. The attractive features of the paper platform include low cost, easy availability, biocompatibility, and hydrophilicity. The standard additions calibration method has the advantages that it can be performed using a single device, eliminates the need for external calibration, and reduces matrix effects associated with the sample and/or non-uniformity of the paper. The method developed was applied in the analysis of certified serum and urine samples. There were no statistically significant differences between the certified concentrations and the results obtained using the paper device with standard additions (Student's t-test at 95% confidence level). Instituto de Química UNESP - Universidade Estadual Paulista “Júlio de Mesquita Filho”, R. Prof. Francisco Degni 55, C.P. 355 Instituto de Química UNESP - Universidade Estadual Paulista “Júlio de Mesquita Filho”, R. Prof. Francisco Degni 55, C.P. 355 CNPq: #140503/2016-1 FAPESP: #2015/21733-1 FAPESP: #2016/20847-6

Made available in DSpace on 2020-12-12T02:30:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-02-15 Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) This paper describes the development and application of a paper-based analytical device (μPAD) for the determination of hydrogen peroxide, an important adulterant in milk. The method employs the reaction between hydrogen peroxide and guaiacol, catalyzed by peroxidase, producing a red product, which is then quantified by digital imaging. Experimental design methodology was used to optimize the experimental conditions. The linear concentration range was from 12.5 × 10− 4 to 150 × 10− 4 mol L− 1, resulting in the regression equation AB = 0.02466 (±0.00192) + 17.053 (±0.750) C, with an excellent correlation coefficient (r = 0.986). The relative standard deviations obtained were 1.1 and 1.3% (intra-day), and 4.8 and 2.9% (inter-day), for 25.0 × 10−4 and 100 × 10−4 mol L−1 of hydrogen peroxide, respectively. The limits of detection and quantification were 3.54 × 10− 4 and 11.8 × 10− 4 mol L− 1, respectively, with standard deviation of the blank of 0.002012. The proposed method was successfully applied for the determination of peroxide in milk samples, with recoveries between 92.2 and 109%. The proposed device constitutes a valuable analytical tool for the identification of hydrogen peroxide adulteration and offers advantages including low cost, simplicity, portability, and no (or minimal) requirement for sample pretreatment. Instituto de Química UNESP – São Paulo State University, R. Prof. Francisco Degni 55, P.O.Box 355 Instituto de Química UNESP – São Paulo State University, R. Prof. Francisco Degni 55, P.O.Box 355 FAPESP: #2015/21733-1 CAPES: 001

Made available in DSpace on 2019-10-06T16:59:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-05-01 Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) New and reliable methodologies are described for the determination of amino acids in gym supplements, offering rapid and clean analysis, with low generation of waste. The proposed methods are based on the reaction between ninhydrin and amino acids in acetate buffer medium (pH 4.75). Experimental design tools were used to optimize the analytical conditions. The linear range obtained for both methodologies was 20.0–350.0 mg L−1. The detection (LOD) and quantification (LOQ) limits were 6.2 and 21.0 mg L−1, respectively, for diffuse reflectance using a paper filter with hydrophobic barriers to increase the sensitivity and homogeneity of the colored product, and 5.7 and 18.8 mg L−1, respectively, for digital image analysis. A USB device was used in the diffuse reflectance spectroscopy method for heating the filter paper, providing speed and portability for the developed methodology. The methods showed good results when applied to gym supplement samples, with recoveries in the range 93.1–110%. Instituto de Química Universidade Estadual Paulista “Julio de Mesquita Filho” UNESP, R. Prof. Francisco Degni 55, P.O. Box 355 Instituto de Química Universidade Estadual Paulista “Julio de Mesquita Filho” UNESP, R. Prof. Francisco Degni 55, P.O. Box 355 FAPESP: 2015/21733-1

Made available in DSpace on 2018-11-28T09:04:16Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-01-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) A colorimetric method based on silver nanoparticles was developed for the determination of melamine in milk. Silver nanoparticles were synthesized without any stabilizer, using sodium borohydride as the reducing agent. Optimization of the variables for the formation of the nanoparticles was performed by factorial design, resulting in stable colloidal silver nanoparticles with a mean diameter of 14.0. 2.7 nm. Spectrophotometric measurements performed at 475 nm showed a linear range from 0.033 to 1.50 mg L-1 of melamine with limits of detection and quantification of 0.009 and 0.031 mg L-1, respectively. The method provided highly sensitive determination of melamine in milk. Univ Estadual Paulista, Inst Quim, R Prof Francisco Degni 55,POB 355, BR-14800900 Sao Paulo, Brazil Univ Estadual Paulista, Inst Quim, R Prof Francisco Degni 55,POB 355, BR-14800900 Sao Paulo, Brazil

This work describes the development and application of a simple, fast, cheap, and clean method for the detection of adulteration of raw cow's milk by urea, using a combined spot test/diffuse reflectance spectroscopy procedure. The proposed method is based on the reaction of urea with a chromogenic reagent, p-dimethylaminobenzaldehyde (p-DAB) in acidified methanol, yielding a colored compound on the surface of a filter paper. The reaction parameters were optimized using chemometric experimental design. Reflectometric measurements of the colored product were carried out at 440 nm. The linear range was from 25 to 750 mg L−1 (R = 0.992). The proposed method was successfully applied in the analysis of urea in cow's milk samples, demonstrating that it is a reliable alternative method for the screening and detection of urea in cow's milk.

Made available in DSpace on 2018-12-11T17:30:28Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-04-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Federación Española de Enfermedades Raras Fundação para a Ciência e a Tecnologia This paper describes the development of a real-time method based on near-infrared spectroscopy (NIRS) for determination of total antioxidant capacity (TAC) and total phenolic content (TPC) in coffee during the roasting process. The real-time non-invasive monitoring procedure involved pointing a diffuse reflectance probe directly at the roasting chamber through a glass window in order to monitor the roasting process. The figures of merit of the chemometric models to estimate TAC and TPC showed selectivity values higher than 12% and determination coefficients (R2 P) above 0.90. The TAC and TPC profiles during the roasting procedure are discussed in terms of the antioxidant compounds likely to be present in green and roasted coffee. NIRS was found to be a satisfactory real-time tool for monitoring the content of antioxidant compounds in coffee during the roasting process, complementing other established procedures. Institute of Chemistry State University of São Paulo - UNESP, R. Prof. Francisco Degni 55, P.O. Box 355 REQUIMTE/LAQV - Departamento de Ciências Químicas Laboratório de Química Aplicada Faculdade de Farmácia Universidade do Porto REQUIMTE/LAQV - Departamento de Química e Bioquímica Faculdade de Ciências Universidade do Porto Research Institute for Medicines (iMed.ULisboa) Faculdade de Farmácia Universidade de Lisboa Institute of Chemistry State University of São Paulo - UNESP, R. Prof. Francisco Degni 55, P.O. Box 355 CAPES: PDSE #99999.000655/2015-05 Federación Española de Enfermedades Raras: PT2020 - UID/ QUI/50006/2013 -POCI/01/0145/FEDER/007265 Fundação para a Ciência e a Tecnologia: SFRH/BPD/81384/2011 Federación Española de Enfermedades Raras: TE-01-0145-FEDER-000011

Made available in DSpace on 2018-12-11T17:28:53Z (GMT). No. of bitstreams: 0 Previous issue date: 2016-09-01 A simple, rapid, and efficient ultrasound-assisted dispersive liquid–liquid microextraction (US-DLLME) method was developed for extraction of tetracycline residues from egg supplement samples, with subsequent determination by flow injection analysis (FIA) coupled to a liquid waveguide capillary cell (LWCC) and a controlled temperature heating bath. Tetracyclines react with diazotized p-sulfanilic acid, in a slightly alkaline medium, to form azo compounds that can be measured at 435 nm. The reaction sensitivity improved substantially (5.12-fold) using an in-line heating temperature of 45 °C. Multivariate methodology was used to optimize the factors affecting the extraction efficiency, considering the volumes of extraction and disperser solvents, sonication time, extraction time, and centrifugation time. Good linearity in the range 30–600 μg L−1 was obtained for all the tetracyclines, with regression coefficients (r) higher than 0.9974. The limits of detection ranged from 6.4 to 11.1 μg L−1, and the recoveries were in the range 85.7–96.4 %, with relative standard deviation lower than 9.8 %. Analyte recovery was improved by approximately 6 % when the microextraction was assisted by ultrasound. The results obtained with the proposed US-DLLME-FIA method were confirmed by a reference HPLC method and showed that the egg supplement samples analyzed were suitable for human consumption. Institute of Chemistry State University of São Paulo—UNESP, R. Prof. Francisco Degni 55, P.O. Box 355 Institute of Chemistry State University of São Paulo—UNESP, R. Prof. Francisco Degni 55, P.O. Box 355

This paper provides, for the first time, an overview of different aspects related to the quality of coffee beans and their volatile fractions: species/cultivars, geographic origins, bean defects, and types of beverages, processing, roasting, and storage. In other words, it concerns the complex relation between the quality of coffee seeds and their volatile components. It is an overview of 48 articles and considering 6 different aspects related to the quality of coffee and its aromatic fraction. The greatest numbers of published papers concerned “species and cultivars” and “defective seeds,” both with 11 articles cited, followed by “storage” with 10 articles. Many aspects still require greater clarification, including the effects of geographical origin, processing, and roasting. Other issues that are better understood include the effects of species type, defective seeds, and storage conditions. Another topic that has received very little attention is the question of the existence of many different coffee cultivars within each species, which we believe should be further investigated, given that this can significantly affect the quality of the final beverage. Meanwhile, with the growing technological development in the areas of science and agriculture, there are many other aspects to be studied (or revisited), and the field of the aromatic quality of coffee provides ample opportunity for scientific investigation.

Made available in DSpace on 2018-12-11T17:37:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-11-05 A simple, fast, low-cost, portable, and eco-friendly method using a spot test on a paper platform, together with diffuse reflectance spectroscopy, was developed and validated for the quantification of aluminum hydrochloride, a potential neurotoxic agent, in antiperspirant samples. The determination of aluminum hydrochloride was performed at a wavelength of 615 nm, by measuring consumption of the purple colorimetric reagent Alizarin S, due to reaction with aluminum. The linear range was from 10.0 to 125.0 mg L−1 and could be described by the equation: AR = 0.4479 − 0.002543 CAl (R = 0.999). The limits of detection (LOD) and quantification (LOQ) were 3.06 and 10.2 mg L−1, respectively. The method was specific, accurate, and repeatable, with relative standard deviation (RSD)

Made available in DSpace on 2018-11-30T03:55:48Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-10-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Counterfeiting and adulteration of pharmaceuticals is a prevalent problem worldwide and represents a major health risk to the population, with anabolic steroids being one of the main classes of drugs consumed and obtained from dubious sources. In this work, we propose the use of the H-1 NMR technique to evaluate formulations containing anabolic steroids, with analysis of 40 samples of anabolic drugs that are used in injectable and capsule forms. The samples analyzed presented the following active ingredients: testosterone propionate, testosterone phenylpropionate, testosterone isocaproate, testosterone decanoate, testosterone cypionate, testosterone undecanoate, stanozolol, drostanolone propionate, trenbolone acetate, oxymetholone, and methandrostenolone. The H-1 NMR spectroscopic measurements were performed using a 600 MHz Bruker Avance III spectrometer, with deuterated chloroform (CDCl3) containing 0.1% TMS as solvent. Of the 40 samples analyzed, eight did not show the presence of the active principle stated on the label. Three types of adulteration were found in the analyzed samples: absence of the active ingredient, adulteration with other substances, and concentration values below those indicated on the label. Sildenafil citrate was found in four samples. The GC-MS technique was used to confirm the adulteration results found using H-1 NMR. Quantitative determination by NMR was performed using internal standard and ERETIC 2 methods, and the results obtained were statistically the same. Sao Paulo State Univ Julio de Mesquita Filho, Inst Chem, BR-14800060 Araraquara, SP, Brazil Sao Paulo State Univ Julio de Mesquita Filho, Inst Chem, BR-14800060 Araraquara, SP, Brazil

An easy and greener flow injection method was developed for the spectrophotometric screening of tetracycline antibiotic residues in bovine milk. The combined benefits of the use of a detection system based on a liquid waveguide capillary cell (LWCC) and stop-flow (60 s) conditions significantly enhanced (45.6-fold) the analytical sensitivity. The determination is based on the formation of tetracycline azo derivatives (λmax = 435 nm) from diazotized p-sulfanilic acid, in a slightly alkaline medium. The analytical conditions were optimized by multivariate analysis, using a fractional factorial design. The linear range was 50–400 μg L−1, and the limits of detection and quantification were in the ranges 8.6–12.2 μg L−1 and 28.8–40.7 μg L−1, respectively. The applicability of the LWCC-based method was successfully tested using fortified milk samples that were only submitted to a prior acid treatment. The screening provided a quick response, enabling the determination of whether the tetracyclines were above or below the limit established by legislation (100 μg L−1). The positive samples were also analyzed by an AOAC Official Method, and the results obtained with the two methods were in good agreement. Additionally, the presence of tetracycline residues was confirmed using an HPLC-MS/MS reference analytical procedure. The excellent performance of the new screening method makes it suitable for use in the quality control of bovine milk in the food industry, aiming at consumer protection.

In this paper we propose a new, fast, simple, economical, portable and environmentally friendly analytical methodology for the determination of copper(II) ions in whisky and sugarcane spirit, using the combination of spot-test and diffuse reflectance spectroscopy. The method is based on the reflectance measurements at 559 nm, of the complex formed from the spot test reaction between the copper(II) ions with the chromogenic agent 1-(2-pyridylazo)-2-naphthol (PAN), using filter paper as the solid support. The best conditions for the reaction occurred with the addition of 30 μL of a PAN solution at a concentration rate of 0.12% m/v in ethanol and 30 μL of an alcoholic solution of copper(II) ions at 40.0% v/v with pH 5.00 and 5 minutes of reaction time. The following elements were found to interfere in the reaction process – iron(III), nickel(II), cobalt(II), cadmium(II), manganese(II), zinc(II) and lead(II) ions. Malonic acid and sodium triphosphate at a concentration of 0.25% m/v were therefore used as masking agents, which contributed towards the reduction of the magnitude of the interference effect from around 20.3% to approximately 2.0%. Under optimized conditions for the determination of copper(II), the analytical curve obtained could be described by: ΔAR = 0.0121CCu(II) + 0.0038 (R2 = 0.9982). Linearity was obtained up to a concentration of 10.0 mg L−1 of copper(II), and limits of detection and quantification (calculated using the standard deviation of the blank) were 0.12 and 0.47 mg L−1 of copper(II), respectively. The proposed method was applied for the determination of copper(II) ions in samples of whisky and sugarcane spirit and the results were compared with those obtained by the official method with a 95% level of confidence.

A simple, fast, low cost, and environmentally friendly analytical methodology was developed for the determination of Amaranth dye in foodstuff samples, offering low consumption of reagents. Spot tests were performed using diffuse reflectance spectroscopy measurements at 530 nm of Amaranth dye on the surface of a qualitative filter paper as the solid support. Caramel coloring, an interferent in the analysis, was eluted from the spot test using aliquots of acid buffer. The calibration curve of absorbance (AR) as a function of the square root of the dye concentration ([Amaranth]1/2) was described by: AR = −0.0176 + 14.556 [Amaranth]1/2 (R2 = 0.999). The proposed method showed a linear range of 1.00 × 10−5 to 5.00 × 10−4 mol L−1 and detection and quantification limits of 1.13 × 10−6 and 1.25 × 10−5 mol L−1, respectively. The technique was applied for the determination of Amaranth in foodstuff samples and the results were consistent with those obtained by a comparative method.

An environmentally reliable analytical methodology was developed for direct quantification of tetracycline (TC) and oxytetracycline (OTC) using continuous flow injection analysis with spectrophotometric detection. The method is based on the diazo coupling reaction between the tetracyclines and diazotized sulfanilic acid in a basic medium, resulting in the formation of an intense orange azo compound that presents maximum absorption at 434 nm. Experimental design was used to optimize the analytical conditions. The proposed technique was validated over the concentration range of 1 to 40 μg mL(-1), and was successfully applied to samples of commercial veterinary pharmaceuticals. The detection (LOD) and quantification (LOQ) limits were 0.40 and 1.35 μg mL(-1), respectively. The samples were also analyzed by an HPLC method, and the results showed agreement with the proposed technique. The new flow injection method can be immediately used for quality control purposes in the pharmaceutical industry, facilitating monitoring in real time during the production processes of tetracycline formulations for veterinary use.

Made available in DSpace on 2018-12-11T17:35:39Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-02-01 With globalization, it has become necessary to adopt policies to regulate the coffee market, addressing problems including the authenticity and traceability of products. It is therefore important to establish methodologies that can help to safeguard the interests of producer countries and add value to products. For this purpose, the use of NMR combined with multivariate statistical procedures can be an attractive option. The aim of this study was to develop a fast and effective technique, using 1H NMR coupled with multivariate statistics, to create a fingerprint of roasted coffees, distinguishing them according to the main Brazilian producer regions. Several compounds suitable for differentiating roasted coffees were identified in the fingerprint. Discriminant analysis revealed good distinction among the samples. The compounds catechol, trigonelline, caffeine, and n-methylpyridine were most important for the differentiation. The findings should assist coffee-producing countries in adopting measures to protect their markets and to add value to coffee products. Federal University of Latin American Integration (UNILA), Av. Tancredo Neves, 6731 – Bloco 6 Chemistry Institute UNESP-Universidade Estadual Paulista “Júliode Mesquita Filho” Chemistry Institute UNESP-Universidade Estadual Paulista “Júliode Mesquita Filho”

Made available in DSpace on 2018-12-11T17:33:46Z (GMT). No. of bitstreams: 0 Previous issue date: 2018-01-15 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) A sensitive, rapid and robust method based on the use of stabilizer-free silver nanoparticles was developed for lead detection in honey. Silver nanoparticles were synthesized without the presence of any stabilizers using silver nitrate and sodium borohydride as precursors where the latter was applied as reducing agent. The optimization of the experimental variables (AgNO3 and NaBH4) for the formation of the nanoparticles was carried out using varying volumes of these solutions. Spectrophotometric measurements at 393 nm showed a linear working range between 0.0500 and 0.167 mg L− 1 lead (R = 0.994), with limits of detection (LOD) and quantification (LOQ) of 0.0135 and 0.0451 mg L− 1, respectively. The proposed method proved to be a significantly sensitive mechanism for lead detection in honey samples. Institute of Chemistry Sao Paulo State University (UNESP), Rua Prof. Francisco Degni 55, P.O. Box 355 Institute of Chemistry Sao Paulo State University (UNESP), Rua Prof. Francisco Degni 55, P.O. Box 355

Coffee is a ubiquitous food product of considerable economic importance to the countries that produce and export it. The adulteration of roasted coffee is a strategy used to reduce costs. Conventional methods employed to identify adulteration in roasted and ground coffee involve optical and electron microscopy, which require pretreatment of samples and are time-consuming and subjective. Other analytical techniques have been studied that might be more reliable, reproducible, and widely applicable. The present review provides an overview of three analytical approaches (physical, chemical, and biological) to the identification of coffee adulteration. A total of 30 published articles are considered. It is concluded that despite the existence of a number of excellent studies in this area, there still remains a lack of a suitably sensitive and widely applicable methodology able to take into account the various different aspects of adulteration, considering coffee varieties, defective beans, and external agents.

A new, simple, rapid and sensitive flow injection spectrophotometric method was developed for the screening and determination of sulphonamides in bovine milk samples. The method is based on the condensation of sulphathiazole, sulphamethazine, and sulphadimethoxine with p-dimethylaminobenzaldehyde (p-DAB) in acid medium, in the presence of sodium dodecyl sulphate (SDS), producing a yellow compound (λmax=465 nm). Optimisation of the experimental parameters was performed using a multivariate methodology. The linear range was 90-500 μg/L and the limits of detection and quantification were in the ranges 25-29 μg/L and 84-88 μg/L, respectively. The procedure was applied for the determination of sulphonamide antibiotics in bovine milk samples submitted to a prior extraction procedure based on QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) methodology. Recoveries of 60.5-70.5% were achieved for milk samples spiked with 0.09, 0.1, 0.2, and 0.3 μg/g of each sulphonamide.

Tetracyclines are widely used for both the treatment and prevention of diseases in animals as well as for the promotion of rapid animal growth and weight gain. This practice may result in trace amounts of these drugs in products of animal origin, such as milk and eggs, posing serious risks to human health. The presence of tetracycline residues in foods can lead to the transmission of antibiotic-resistant pathogenic bacteria through the food chain. In order to ensure food safety and avoid exposure to these substances, national and international regulatory agencies have established tolerance levels for authorized veterinary drugs, including tetracycline antimicrobials. In view of that, numerous sensitive and specific methods have been developed for the quantification of these compounds in different food matrices. One will note, however, that the determination of trace residues in foods such as milk and eggs often requires extensive sample extraction and preparation prior to conducting instrumental analysis. Sample pretreatment is usually the most complicated step in the analytical process and covers both cleaning and pre-concentration. Optimal sample preparation can reduce analysis time and sources of error, enhance sensitivity, apart from enabling unequivocal identification, confirmation and quantification of target analytes. The development and implementation of more environmentally friendly analytical procedures, which involve the use of less hazardous solvents and smaller sample sizes compared to traditional methods, is a rapidly increasing trend in analytical chemistry. This review seeks to provide an updated overview of the main trends in sample preparation for the determination of tetracycline residues in foodstuffs. The applicability of several extraction and clean-up techniques employed in the analysis of foodstuffs, especially milk and egg samples, is also thoroughly discussed. Fil: Pérez Rodríguez, Michael. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Química Básica y Aplicada del Nordeste Argentino. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Instituto de Química Básica y Aplicada del Nordeste Argentino; Argentina Fil: Pellerano, Roberto Gerardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Química Básica y Aplicada del Nordeste Argentino. Universidad Nacional del Nordeste. Facultad de Ciencias Exactas Naturales y Agrimensura. Instituto de Química Básica y Aplicada del Nordeste Argentino; Argentina Fil: Pezza, Leonardo. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil Fil: Redigolo Pezza, Helena. Universidade Estadual Paulista Julio de Mesquita Filho; Brasil

Made available in DSpace on 2018-12-11T17:32:57Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-11-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fuel Cell Technologies Office Semiconductor quantum dots (QDs) have demonstrated a great potential as fluorescent probes for heavy metals monitoring. However, their great reactivity, whose tunability could be difficult to attain, could impair selectivity yielding analytical results with poor accuracy. In this work, the combination in the same analysis of multiple QDs, each with a particular ability to interact with the analyte, assured a multi-point detection that was not only exploited for a more precise analyte discrimination but also for the simultaneous discrimination of multiple mutually interfering species, in the same sample. Three different MPA-CdTe QDs (2.5, 3.0 and 3.8 nm) with a good size distribution, confirmed by the FWHM values of 48.6, 55.4 and 80.8 nm, respectively, were used. Principal component analysis (PCA) and partial least squares regression (PLS) were used for fluorescence data analysis. Mixtures of two MPA-CdTe QDs, emitting at different wavelength namely 549/566, 549/634 and 566/634 nm were assayed. The 549/634 nm emitting QDs mixture provided the best results for the discrimination of distinct ions on binary and ternary mixtures. The obtained RMSECV and R2CV values for the binary mixture were good, namely, from 0.01 to 0.08 mg L−1 and from 0.74 to 0.89, respectively. Regarding the ternary mixture the RMSECV and R2CV values were good for Hg(II) (0.06 and 0.73 mg L−1, respectively) and Pb(II) (0.08 and 0.87 mg L−1, respectively) and acceptable for Cu(II) (0.02 and 0.51 mg L−1, respectively). In conclusion, the obtained results showed that the developed approach is capable of resolve binary and ternary mixtures of Pb (II), Hg (II) and Cu (II), providing accurate information about lead (II) and mercury (II) concentration and signaling the occurrence of Cu (II). Instituto de Química Universidade Estadual Paulista “Júlio de Mesquita Filho” UNESP, R. Prof. Francisco Degni 55, P.O. Box 355 LAQV REQUIMTE Department of Chemical Sciences Laboratory of Applied Chemistry Faculty of Pharmacy University of Porto, Rua de Jorge Viterbo Ferreira no 228 Instituto de Química Universidade Estadual Paulista “Júlio de Mesquita Filho” UNESP, R. Prof. Francisco Degni 55, P.O. Box 355 CAPES: 99999.000651/2015-00 Fuel Cell Technologies Office: SFRH/BPD/104638/2014