O consumo do pescado é importante para a saúde humana pelo fato desse alimento ser fonte de proteína de alta qualidade, vitaminas, nutrientes essenciais e dois ácidos poli-insaturados ômega-3. Entretanto, o pescado também pode apresentar risco à saúde humana se estiver contaminado por substâncias tóxicas. Visando avaliar o teor de elementos essenciais e tóxicos, foram utilizado as técnicas de Análise por Ativação Neutrônica e Espectrometria de Absorção Atômica na determinação dos elementos As, Br, Cd, Cl, Co, Cr, Cs, Fe, Hg, K, Mg, Mn, Na, Pb, Rb, Sb, Se e Zn nos tecidos comestíveis (filés) de seis pescados dentre os mais consumidos na cidade de São Paulo: corvina - Micropogonias furnieri (Desmarest, 1823); pescada - Cynoscion leiarchus (Cuvier, 1830); robalo - Centropomus undecimalis (Bloch, 1792); sardinha - Sardinella brasiliensis (Steindachner, 1879); anchova - Pomatomus saltatrix (Linnaeus, 1766) e tainha - Mugil liza (Valenciennes, 1836). Para validar os métodos analíticos utilizados em relação à exatidão, foram utilizados o índice z e o valor de HorRat em materiais de referência certificados analisados sob as mesmas condições das amostras. Os elementos Br, K e Na foram determinados por duas modalidades de irradiação e o teste-t de Student foi utilizado para verificar se havia ou não diferença significativa entre as técnicas. Na determinação dos elementos essenciais e potencialmente tóxicos, foi possível a construção de banco de dados para os elementos Br, Cl, Co, Cs, Fe, K, Mg, Mn, Na, Rb, Se e Zn para potenciais futuras discussões. Para avaliar se havia ou não risco à segurança alimentar, foram comparado os teores de As, Cd, Hg e Pb com a legislação vigente no Brasil e com valores internacionais. Em relação à segurança alimentar, para os contaminantes Cd e Pb foram obtidos teores abaixo de todos os limites técnicos usados neste trabalho. Para As, a maior parte deve estar na forma orgânica, portanto, a determinação de Hg se mostrou determinante. De forma geral, não haveria perigo no consumo da sardinha, pescada, tainha, corvina e robalo, enquanto que para a anchova foi inconclusivo. / Fish consumption is important for human health because this food is a source of high-quality protein, vitamins, essential nutrients and two kinds of omega-3 polyunsaturated acids. However, fish consumption may present risk to human health if contaminated by toxic substances. With the aim of evaluating the content of essential and toxic elements, the techniques of Instrumental Neutron Activation Analysis and Atomic Absorption Spectrometry were used to determine As, Br, Cd, Cl, Co, Cr, Cs, Fe, Hg, K, Mg, Mn, Na, Pb, Rb, Sb, Se and Zn in the edible tissues (fillet) of six of the most consumed fishes at São Paulo city: whitemouth croaker - Micropogonias furnieri (Desmarest, 1823), smooth weakfish - Cynoscion leiarchus (Cuvier, 1830), common snook - Centropomus undecimalis (Bloch, 1792), Brazilian sardine - Sardinella brasiliensis (Steindachner, 1879), bluefish - Pomatomus saltatrix (Linnaeus, 1766) and lebranche mullet - Mugil liza (Valenciennes, 1836). To validate the analytical methods for accuracy, z-score and HorRat values were applied to certified reference materials analyzed under the same conditions of samples. The elements Br, K and Na were determined by two irradiation modalities, and the Student\'s t-test was used to verify whether there were significant differences between the modalities. In the analysis of essential and potentially toxic elements, it was possible to create a database for Br, Cl, Co, Cs, Fe, K, Mg, Mn, Na, Rb, Se and Zn for potential future discussions. In order to assess food safety risks, the levels of As, Cd, Hg and Pb were compared with the Brazilians law and international values. Regarding food safety, Cd and Pb contents were bellow all technical limits used in this study. As for As, most part of this element may be in organic form, therefore the Hg analysis was determinant. In general, there would be no risk in the consumption of Brazilian sardine, smooth weakfish, lebranche mullet, whitemouth croaker and common snook, while for bluefish it was inconclusive.

<p>Laser-based absorption spectroscopy (AS) is a powerful technique for qualitative and quantitative studies of atoms and molecules. An important field of use of AS is the detection of species in trace concentrations, which has applications not only in physics and chemistry but also in biology and medicine, encompassing environmental monitoring, regulation of industrial processes and breath analysis. Although a large number of molecular species can successfully be detected with established AS techniques, there are some applications that require higher sensitivity, selectivity and accuracy, yet robust and compact instrumentation.</p><p>Various approaches have been made during the years to improve on the performance of AS, usually based on modulation spectrometry or external cavities. The most sensitive absorption technique of today is, however, noise-immune cavity-enhanced optical heterodyne molecular spectroscopy (NICE-OHMS). This technique elegantly combines several approaches: external cavities (for optical path length enhancement), modulation techniques (for noise reduction) and saturation spectroscopy (for enhanced selectivity). However, due to its complexity, the technique has so far not been applied to practical trace species detection.</p><p>This thesis provides the background for an understanding of NICE-OHMS and describes the construction of a first compact NICE-OHMS spectrometer based on a narrowband fiber laser. Moreover, it gives theoretical expressions for NICE-OHMS signal lineshapes, measured in various modes of detection, which can be fitted to the experimental data and thereby facilitate the assessment of species concentration. The sensitivity of the instrumentation is demonstrated by detection of acetylene (C₂H₂) and carbon dioxide (CO₂) in the 1.5 μm region. A fractional absorption sensitivity of 3*10^-9 (integrated absorption of 5*10^-11 cm^-1), could be achieved using a cavity with a finesse of 4800 and an acquisition time of 0.7 s. This results in a detection limit for C₂H₂ of 4.5 ppt (4.5*10^-12 atm).</p><p>In addition, the thesis revives the idea of using an accurate (frequency) measurement of the free-spectral-range (FSR) of an external cavity for sensitive and calibration-free concentration assessment. A theoretical description of the expected signal lineshapes is given, and in a first experimental demonstration the FSR could be measured with a resolution of 5 Hz, resulting in a fractional absorption sensitivity of 1*10^-7, and subsequently in a detection limit for C₂H₂ of 180 ppt (12.5 s acquisition time).</p><p>The thesis, finally, also contributes to the continuously ongoing development of conventional AS and wavelength modulated AS by addressing concepts related to when the light optically saturates the transition.</p>

Laser-based absorption spectroscopy (AS) is a powerful technique for qualitative and quantitative studies of atoms and molecules. An important field of use of AS is the detection of species in trace concentrations, which has applications not only in physics and chemistry but also in biology and medicine, encompassing environmental monitoring, regulation of industrial processes and breath analysis. Although a large number of molecular species can successfully be detected with established AS techniques, there are some applications that require higher sensitivity, selectivity and accuracy, yet robust and compact instrumentation. Various approaches have been made during the years to improve on the performance of AS, usually based on modulation spectrometry or external cavities. The most sensitive absorption technique of today is, however, noise-immune cavity-enhanced optical heterodyne molecular spectroscopy (NICE-OHMS). This technique elegantly combines several approaches: external cavities (for optical path length enhancement), modulation techniques (for noise reduction) and saturation spectroscopy (for enhanced selectivity). However, due to its complexity, the technique has so far not been applied to practical trace species detection. This thesis provides the background for an understanding of NICE-OHMS and describes the construction of a first compact NICE-OHMS spectrometer based on a narrowband fiber laser. Moreover, it gives theoretical expressions for NICE-OHMS signal lineshapes, measured in various modes of detection, which can be fitted to the experimental data and thereby facilitate the assessment of species concentration. The sensitivity of the instrumentation is demonstrated by detection of acetylene (C2H2) and carbon dioxide (CO2) in the 1.5 μm region. A fractional absorption sensitivity of 3*10-9 (integrated absorption of 5*10-11 cm-1), could be achieved using a cavity with a finesse of 4800 and an acquisition time of 0.7 s. This results in a detection limit for C2H2 of 4.5 ppt (4.5*10-12 atm). In addition, the thesis revives the idea of using an accurate (frequency) measurement of the free-spectral-range (FSR) of an external cavity for sensitive and calibration-free concentration assessment. A theoretical description of the expected signal lineshapes is given, and in a first experimental demonstration the FSR could be measured with a resolution of 5 Hz, resulting in a fractional absorption sensitivity of 1*10-7, and subsequently in a detection limit for C2H2 of 180 ppt (12.5 s acquisition time). The thesis, finally, also contributes to the continuously ongoing development of conventional AS and wavelength modulated AS by addressing concepts related to when the light optically saturates the transition.

Noise-immune cavity-enhanced optical heterodyne molecular spectro-metry (NICE-OHMS) is one of the most sensitive laser-based absorption techniques. The high sensitivity of NICE-OHMS is obtained by a unique combination of cavity enhancement (for increased interaction length with a sample) with frequency modulation spectrometry (for reduction of noise). Moreover, sub-Doppler detection is possible due to the presence of high intensity counter-propagating waves inside an external resonator, which provides an excellent spectral selectivity. The high sensitivity and selectivity make NICE-OHMS particularly suitable for trace gas detection. Despite this, the technique has so far not been often used for practical applications due to its technical complexity, originating primarily from the requirement of an active stabilization of the laser frequency to a cavity mode. The main aim of the work presented in this thesis has been to develop a simpler and more robust NICE-OHMS instrumentation without compro-mising the high sensitivity and selectivity of the technique. A compact NICE-OHMS setup based on a fiber laser and a fiber-coupled electro-optic modulator has been constructed. The main advantage of the fiber laser is its narrow free-running linewidth, which significantly simplifies the frequency stabilization procedure. It has been demonstrated, using acetylene and carbon dioxide as pilot species, that the system is capable of detecting relative absorption down to 3 × 10-9 on a Doppler-broadened transition, and sub-Doppler optical phase shift down to 1.6 × 10-10, the latter corresponding to a detection limit of 1 × 10-12 atm of C2H2. Moreover, the potential of dual frequency modulation dispersion spectrometry (DFM-DS), an integral part of NICE-OHMS, for concentration measurements has been assessed. This thesis contributes also to the theoretical description of Doppler-broadened and sub-Doppler NICE-OHMS signals, as well as DFM-DS signals. It has been shown that the concentration of an analyte can be deduced from a Doppler-broadened NICE-OHMS signal detected at an arbitrary and unknown detection phase, provided that a fit of the theoretical lineshape to the experimental data is performed. The influence of optical saturation on Doppler-broadened NICE-OHMS signals has been described theoretically and demonstrated experimentally. In particular, it has been shown that the Doppler-broadened dispersion signal is unaffected by optical saturation in the Doppler limit. An expression for the sub-Doppler optical phase shift, valid for high degrees of saturation, has been derived and verified experimentally up to degrees of saturation of 100.

The use of slotted quartz tube (SQT) as an atom trap in atomic absorption spectrometry (AAS) provides a more stable chemical environment for atomization / the technique is simple and easily applicable in any laboratory. This thesis study involves application of SQT together with some other approaches to thallium determination by AAS. The first stages involve the efforts to improve nebulization efficiency of conventional flame atomic absorption spectrometry (FAAS) with and without the use of SQT. This is achieved by mixing 100 &micro / L of propanol with 500 &micro / L of Tl standard solution using the optimum conditions. By this method, Propanol-SQT-FAAS, 4.49 times enhancement in sensitivity has been obtained with respect to conventional FAAS, method in which the characteristic concentration was calculated as 894 ng/mL. The second stage of investigation is about the use of SQT as an atom trap, AT, preconcentration device for thallium determination. The similar technique has been successfully applied to some other analytes such as Pb, Cd, Bi and Au / detection limits at the level of ng/mL were obtained in the previous studies. In the present work, the analyte atoms are trapped on the inner surface of SQT in the presence of a lean air-acetylene flame for few minutes. After this collection step, a volume of methyl isobutyl ketone, MIBK, amounting to 10-50 microliters is introduced via conventional nebulization / this causes a momentary alteration in the flame composition and thus results in the release of trapped analyte atoms from the quartz surface. This revolatilization step is followed by a rapid atomization and transient signal was obtained. In addition to this method, a novel approach has been investigated where the inner surface of SQT was modified by using a metal coating with low volatility. For this purpose, eight different coating materials which were tungsten, palladium, molybdenum, gold, tantalum, zirconium, titanium and osmium, have been applied to the inner surface of SQT and as osmium was found to be most appropriate one, the rest of the study was continued with Os-Coated-SQT. This modification provided a better surface than quartz alone so that analyte atoms are trapped more efficiently and also released easily. Although the working principle of the Coated-SQT-AT-FAAS method is same with SQT-AT-FAAS, the conditions for SQT-AT-FAAS and Os-Coated-SQT-AT-FAAS methods were optimized seperately. Limit of detections, 3s/m, has been found to be 38 ng/mL and 3.5 ng/mL for these cases, respectively. While the SQT-AT-FAAS method has provided 92 fold enhancement, the Os-Coated-SQT-AT-FAAS method has provided a 319 fold sensitivity improvement with respect to conventional FAAS method.

This work deals with the determination of metals in soils taken close to the railway. Copper, zinc, nickel and chromium were selected as indicators of the environment contamination. Samples were taken from three localities in South Bohemia. These localities were chosen on the basis of different types of railway tracks (electrified and nonelectrified) and different frequency of train connection. Atomic absorption spectrometry was used for the determination of the metals. An AAS Thermo Scientific iCE 3500 spectrometer served to determine individual analytes. The highest level of copper pollution was detected for samples taken close to the railway with electrified track and with high frequency of train connection. The highest Cu concentration (66.30 mg/kg) was determined in the soil sample from 20cm depth. The highest level of zinc pollution was detected for samples taken in the distance of 3 m from the railway with electrified track and with high frequency of train connection. The highest Zn concentration (641.77 mg/kg) was determined in the soil sample from 30cm depth. The highest concentrations of other metals (Ni and Cr) were detected for the railway with nonelectrified track and with low frequency of train connection. The highest concentrations of Ni and Cr were 21.89 and 54.89 mg/kg, respectively. These concentrations were obtained for samples taken close to the railway.

Made available in DSpace on 2014-06-11T19:27:29Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-06-15Bitstream added on 2014-06-13T20:36:06Z : No. of bitstreams: 1 santos_fa_me_botfmvz.pdf: 1235942 bytes, checksum: 7b3f579b06b2874c741bde8ef170587e (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Universidade Estadual Paulista (UNESP) / O presente trabalho teve como objetivo investigar a presença de manganês e zinco em “spots” protéicos de amostras de plasma de tilápia do Nilo (Oreochromis niloticus) obtidos após separação das proteínas por eletroforese em gel de poliacrilamida em segunda dimensão (2D-PAGE) para posterior avaliação qualitativa e quantitativa utilizando fluorescência de raios-X com radiação síncrotron (SR-XRF) e espectrometria de absorção atômica em chama e em forno de grafite (FAAS/GFAAS). As análises dos espectros de fluorescência indicaram a presença de manganês e zinco em quatro e seis “spots” protéicos de plasma, respectivamente. Observou-se que os íons metálicos estão ligados em proteínas com massa molar na faixa de 19 a 70 kDa e com pI na faixa de 4,7 a 6,30. A concentração de manganês e zinco ligados a essas proteínas foi determinada por GFAAS após a mineralização ácida dos spots protéicos, encontrandose concentrações na faixa de 3,40 a 4,20 mg g-1 e 2,30 a 13,90 mg g-1, respectivamente / The aim of the present study was to investigate the presence of manganese and zinc in protein spots in samples of Nile tilapia (Oreochromis niloticus) plasma obtained after protein separation by two-dimensional polyacrylamide gel electrophoresis (2D PAGE) and subsequent qualitative and quantitative determination by synchrotron radiation X-ray fluorescence (SRXRF) and graphite furnace atomic absorption spectrometry (GFAAS). An analysis of the fluorescence spectra indicated the presence of manganese and zinc in four and six plasma protein spots, respectively. It was observed that the metal ions are bound in proteins with molecular weight ranging from 19 to 70 kDa and pI ranging from 4.7 to 6.30. The manganese and zinc concentrations bound to these proteins were determined by GFAAS after acid digestion of protein spots, finding concentrations ranging from 3.40 to 4.20 mg g-1 and 2.30 to 13.90 mg g - 1, respectively

Orientador: Pedro de Magalhães Padilha / Banca: Gustavo Rocha de Castro / Banca: Eduardo José de Arruda / Resumo: O presente trabalho teve como objetivo investigar a presença de manganês e zinco em "spots" protéicos de amostras de plasma de tilápia do Nilo (Oreochromis niloticus) obtidos após separação das proteínas por eletroforese em gel de poliacrilamida em segunda dimensão (2D-PAGE) para posterior avaliação qualitativa e quantitativa utilizando fluorescência de raios-X com radiação síncrotron (SR-XRF) e espectrometria de absorção atômica em chama e em forno de grafite (FAAS/GFAAS). As análises dos espectros de fluorescência indicaram a presença de manganês e zinco em quatro e seis "spots" protéicos de plasma, respectivamente. Observou-se que os íons metálicos estão ligados em proteínas com massa molar na faixa de 19 a 70 kDa e com pI na faixa de 4,7 a 6,30. A concentração de manganês e zinco ligados a essas proteínas foi determinada por GFAAS após a mineralização ácida dos spots protéicos, encontrandose concentrações na faixa de 3,40 a 4,20 mg g-1 e 2,30 a 13,90 mg g-1, respectivamente / Abstract: The aim of the present study was to investigate the presence of manganese and zinc in protein spots in samples of Nile tilapia (Oreochromis niloticus) plasma obtained after protein separation by two-dimensional polyacrylamide gel electrophoresis (2D PAGE) and subsequent qualitative and quantitative determination by synchrotron radiation X-ray fluorescence (SRXRF) and graphite furnace atomic absorption spectrometry (GFAAS). An analysis of the fluorescence spectra indicated the presence of manganese and zinc in four and six plasma protein spots, respectively. It was observed that the metal ions are bound in proteins with molecular weight ranging from 19 to 70 kDa and pI ranging from 4.7 to 6.30. The manganese and zinc concentrations bound to these proteins were determined by GFAAS after acid digestion of protein spots, finding concentrations ranging from 3.40 to 4.20 mg g-1 and 2.30 to 13.90 mg g - 1, respectively / Mestre

Um método de baixo custo é proposto para determinação direta de chumbo em açúcar por espectrometria de absorção atômica com forno de grafite e correção de fundo com fonte de deutério, empregando modificação química permanente com 250µg W + 200µg Rh e co-injeção de 5µg Rh. Os experimentos foram realizados com plataforma integrada ou ao no tubo de grafite com aquecimento longitudinal. Para avaliação da modificação química permanente, foram feitos experimentos na ausência de modificação e na presença de modificação química convencional com Pd+Mg. No decorrer do trabalho observou-se ser imprescindível a co-injeção de Rh para a estabilização térmica de chumbo na presença de açúcar. A amostra (8 g) é dissolvida em 100 ml de solução aquosa 0,2% v/v HNO3, e uma alíquota de 10 l é injetada com 5µl de solução de Rh na plataforma do tubo de grafite modelo Universal da Varian tratada com W e Rh. A massa característica (mo) e o limite de detecção do método foram 11 pg Pb e 5 ng g-1 respectivamente, e a vida útil do tubo de grafite foi de 860 queimas. O método apresentou boa reprodutibilidade com coeficiente de variação inferior a 2,5 % (n=3). As características analíticas foram comparadas com os métodos recomendados na literatura. A exatidão do método proposto para determinação direta de chumbo em açúcar foi avaliada pela comparação com método convencional utilizando Pd+Mg e nenhuma diferença estatística foi observada aplicando-se o teste t de Student ao nível de 95% de probabilidade, em amostras que receberam adição de chumbo / A simple method for the direct determination of lead in sugar by graphite furnace atomic absorption spectrometry (GFAAS) with platform treated with 250µg W + 200µg Rh and deuterium background correction is proposed. Samples (8 g) were dissolved in 100 ml of an aqueous solution containing 0,2% v/v HNO3 and 10µl aliquots were co-injected with 5µg Rh into the integrated platform modified with W-Rh of the Universal Varian longitudinal heated graphite atomizer. The characteristic mass (mo) and the method detection limit were 11 pg Pb and 5,0 ng g-1 Pb, respectively, and the tube life time was 860 firings. The relative standard deviation of measurements (n=3) was lower than 2,5 %. For the evaluation of the permanent chemical modifier, parallel experiments were carried in the presence of diluted nitric acid and with the conventional Pd+Mg chemical modifier. Experiments were made either with manual inserted graphite plataforms or integrated plataforms into longitudinal graphite tubes. Comparison of the proposed method with a method based on Pd+Mg chemical modifier showed no statistical differences by applying a t-test at 95% confidence level, for sugar sample solution spiked with lead

Submitted by Geandra Rodrigues (geandrar@gmail.com) on 2018-10-11T17:08:56Z No. of bitstreams: 1 antoniopedronogueiraguimaraes.pdf: 2143651 bytes, checksum: 2b5f614beda89a6e2938efa513c2b8a7 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2018-10-16T14:22:35Z (GMT) No. of bitstreams: 1 antoniopedronogueiraguimaraes.pdf: 2143651 bytes, checksum: 2b5f614beda89a6e2938efa513c2b8a7 (MD5) / Made available in DSpace on 2018-10-16T14:22:35Z (GMT). No. of bitstreams: 1 antoniopedronogueiraguimaraes.pdf: 2143651 bytes, checksum: 2b5f614beda89a6e2938efa513c2b8a7 (MD5) Previous issue date: 2018-07-31 / Este trabalho descreve métodos de determinação de cromo e manganês nas frações bioacessíveis de suplementos alimentares, como hipercalóricos, whey protein e protein bar por espectrometria de absorção atômica em forno de grafite (GFAAS). Para o desenvolvimento dos métodos, as frações bioacessíveis foram submetidas à digestão assistida por radiação micro-ondas e posterior otimização instrumental das temperaturas de pirólise e atomização. Para o manganês, nas amostras de whey protein e protein bar, obteve-se as mesmas temperaturas de pirólise e atomização: 1100 e 1600 °C, respectivamente; para hipercalóricos foi empregado o uso de modificador químico, Mg(NO3)2, e suas temperaturas de pirólise e atomização foram de 1200 e 1700 °C, respectivamente. Para o cromo, não foi preciso o uso de modificador e as temperaturas de pirólise e atomização otimizadas foram as mesmas para as três amostras: 1500 e 2300 °C, respectivamente. A exatidão dos métodos foi investigada através de ensaios de adição e recuperação de analito, apresentando para o manganês valores na faixa de 84 a 113% e para o cromo, valores entre 101 e 116%. A precisão dos métodos também foi avaliada, mostrando desvios padrões relativos menores que 15%. A massa característica (m0), limites de detecção (LD) e quantificação (LQ) para os métodos de cromo foram de 1,9 pg, 0,07 μg g-1 e 0,2 μg g-1, respectivamente; para manganês em hipercalórico os valores obtidos foram de 1,8 pg, 0,03 e 0,08 μg g-1; já em whey protein e protein bar os mesmos foram de 4,2 pg, 0,12 μg g-1 e 0,3 μg g-1. Os métodos desenvolvidos foram aplicados em 12 amostras de suplementos alimentares, sendo 4 de hipercalóricos, 3 de whey protein e 5 de protein bar. Foram observados valores de porcentagem de bioacessibilidade para cromo: 12% em whey protein, 16% em protein bar e, 39 e 49% em hipercalóricos. Em contrapartida, somente uma amostra de whey protein apresentou porcentagem bioacessível não significativa para manganês, e os resultados variaram de 6 até 99%. / This study describes methods for the determination of two minerals, chromium and manganese, in the bioaccessible fractions of food supplements, like hypercaloric, whey protein and protein bars, by graphite furnace atomic absorption spectrometry. For the development of the methods, the bioaccessible fractions were submitted to digestion assisted by microwave radiation and posterior instrumental optimization of pyrolysis and atomization temperatures. For manganese, whey protein and protein bars samples obtained the same pyrolysis and atomization temperatures: 1100 and 1600 °C, respectively; for hypercaloric, the use of the modifier Mg(NO3)2 was employed and the pyrolysis and atomization temperatures were 1200 and 1700 °C, respectively. For chromium, it was not necessary the modifier and the pyrolysis and atomization temperatures for the three types of samples were 1500 and 2300 °C, respectively. The accuracy of the methods were investigated through addition and recovery tests; for manganese the study showed reveries in a range of 84 to 113% and for chromium in a range of 101 to 116%. The precision of the methods was also evaluated and presented relative standard deviation values smaller than 15%. The characteristic mass (mo), limits of detection (LD) and quantification (LQ) for chromium were 1,9 pg, 0,07 i_tg g-1 and 0,2 i_tg g-1, respectively; for manganese, in hypercaloric the values found were 1,8 pg, 0,03 and 0,08 i_tg g-1; and finally, in whey protein and protein bars the values were 4,2 pg, 0,12 ilg g-1 and 0,3 ilg g-1. The developed methods were applied to 12 food supplement samples, being 4 of hypercaloric, 3 of whey protein and 5 of protein bars. Four of those samples presented chromium bioaccessible percentage: 49 and 39% in hypercaloric, 12% in whey protein and 16% in protein bars. On the other hand, only one sample of whey protein did not present significant manganese bioaccessible percentage, varying in a range of 6 to 99%.