Cristina Barra - Academia.edu (original) (raw)
Papers by Cristina Barra
Urologic Oncology: Seminars and Original Investigations, 2010
The epithelial-mesenchymal transition (EMT) is considered a key step in tumor progression, where ... more The epithelial-mesenchymal transition (EMT) is considered a key step in tumor progression, where the invasive cancer cells change from epithelial to mesenchymal phenotype. During this process, a decrease or loss in adhesion molecules expression and an increase in migration molecules expression are observed. The aim of this work was to determine the expression and cellular distribution of syndecan-1 and -2 (migration molecules) and E-cadherin and beta-catenin (adhesion molecules) in different stages of prostate cancer progression. A quantitative immunohistochemical study of these molecules was carried out in tissue samples from benign prostatic hyperplasia and prostate carcinoma, with low and high Gleason score, obtained from biopsies archives of the Clinic Hospital of the University of Chile and Dipreca Hospital. Polyclonal specific antibodies and amplification system of estreptavidin-biotin peroxidase and diaminobenzidine were used. Syndecan-1 was uniformly expressed in basolateral membranes of normal epithelium, changing to a granular cytoplasmatic expression pattern in carcinomas. Syndecan-2 was observed mainly in a cytoplasmatic granular pattern, with high immunostaining intensity in areas of low Gleason score. E-cadherin was detected in basolateral membrane of normal epithelia showing decreased expression in high Gleason score samples. beta-Catenin was found in cell membranes of normal epithelia changing its distribution toward the nucleus and cytoplasm in carcinoma samples. We concluded that changes in expression and cell distribution of E-cadherin and beta-catenin correlated with the progression degree of prostate adenocarcinoma, suggesting a role of these molecules as markers of progression and prognosis. Furthermore, changes in the pattern expression of syndecan-1 and -2 indicate that both molecules may be involved in the EMT and tumor progression of prostate cancer.
Electroanalysis, 2001
A fast and sensitive voltammetric method for the determination of arsenite and total inorganic ar... more A fast and sensitive voltammetric method for the determination of arsenite and total inorganic arsenic in natural water systems is described using square-wave cathodic stripping voltammetry at a hanging mercury drop electrode. All the determinations were done in 1 M HCl, in the presence of 5 ppm copper(II) and dissolved oxygen. Discrimination between both oxidation states is achieved just by varying the composition of the supporting electrolyte: reduction of As(V) to As(III) is carried out at room temperature by a mixture of potassium iodide and ascorbic acid and inorganic arsenic determined as As(III) þ As(V), while As(III) is measured in the absence of the reducing agent. For an accumulation time of 60 s the detection limits were 0.7 ppb for As(III) in 1 M HCl, and 5 ppm Cu(II), 0.6 ppb for As(III) þ As(V) in 1 M HCl, 5 ppm Cu(II) and 0.04 % (w=v) KI þ 0.02 % (w=v) ascorbic acid. The precision, expressed as relative standard deviation (RSD) at 95 % confidence level, was calculated as 9 % from ten individual measurements taken at 2 ppb standard. The method was tested by the measurement of As(V) and As(III) in real and synthetic natural water samples.
Cadernos de Saúde Pública
Increasing attention is current focused on urban groundwater contamination with gasoline hydrocar... more Increasing attention is current focused on urban groundwater contamination with gasoline hydrocarbon compounds in Brazil. The compounds benzene, toluene, ethylbenzene, and xylenes (BTEX) contained in fuels are highly toxic and can have severe public health consequences, besides posing the risk of intake from the water table by way of contamination. After two years of a steady gasoline storage tank leak, water samples from private household wells in the district of Brisa Mar, Itaguaí, Rio de Janeiro State, were analyzed and the concentration of BTEX compounds was evaluated. Two out of ten water samples from the study area presented BTEX concentrations above the National Water Quality Standard (Brazilian Health Ministry Ruling No. 1469/2000), in which the maximum permissible benzene concentration is 5 micro g.L-1. Four others wells were also contaminated with nitrate, responsible for the induction of methemoglobinemia. Natural attenuation (intrinsic biodegradation) mechanisms through ...
Cadernos de Saúde Pública, 2002
A contaminação de águas subterrâneas por combustível derivado de petróleo tem sido objeto de cres... more A contaminação de águas subterrâneas por combustível derivado de petróleo tem sido objeto de crescente pesquisa no Brasil. Os compostos benzeno, tolueno, etilbenzeno e xilenos (BTEX), presentes nesses combustíveis, são extremamente tóxicos à saúde humana e podem inviabilizar a exploração de aqüíferos por eles contaminados. Neste trabalho, foi feita uma avaliação da qualidade da água de poço de algumas residências do Bairro Brisa Mar, Itaguaí, Rio de Janeiro, quanto à presença dos micropoluentes BTEX após dois anos da ocorrência de um vazamento de gasolina do tanque de armazenamento de combustível. Os resultados mostraram que dos dez poços avaliados, apenas dois encontram-se com valores de BTEX acima do recomendado pela Portaria 1.469/2000 do Ministério de Saúde, em que o teor máximo permitido para o benzeno é de 5µg.L-1. Em quatro poços há contaminação por nitrato, que é responsável pela indução da metemoglobinemia. Foram estudados também os possíveis mecanismos de atenuação natural...
Hormone Research in Paediatrics, 2015
Background: The same reference values for cortisol have been used for adults and children, but la... more Background: The same reference values for cortisol have been used for adults and children, but laboratory results obtained from an adult population might not be suitable for pediatric patients. Aims: To determine morning serum basal cortisol levels in children and adolescents. Methods: The study was conducted on 120 suitable reference individuals, healthy Brazilian children and adolescents from both genders aged 4-19 years old. The method used for cortisol assessment was the chemiluminescent enzyme immunoassay (VITROS® 5600 MicroWell; Johnson & Johnson, High Wycombe, UK, 2009), and the kit reference interval was 4.46-22.7 μg/dl (122.7-626.2 nmol/l). The setting limits were calculated according to the Clinical Laboratory Standards Institute guidelines. Results: The morning serum basal cortisol levels increased with age and pubertal maturation, but there were no differences based on gender. The cortisol reference values were established based on the 2.5th and 97.5th percentiles as 2.9...
Urologic Oncology: Seminars and Original Investigations, 2010
The epithelial-mesenchymal transition (EMT) is considered a key step in tumor progression, where ... more The epithelial-mesenchymal transition (EMT) is considered a key step in tumor progression, where the invasive cancer cells change from epithelial to mesenchymal phenotype. During this process, a decrease or loss in adhesion molecules expression and an increase in migration molecules expression are observed. The aim of this work was to determine the expression and cellular distribution of syndecan-1 and -2 (migration molecules) and E-cadherin and -catenin (adhesion molecules) in different stages of prostate cancer progression. A quantitative immunohistochemical study of these molecules was carried out in tissue samples from benign prostatic hyperplasia and prostate carcinoma, with low and high Gleason score, obtained from biopsies archives of the Clinic Hospital of the University of Chile and Dipreca Hospital. Polyclonal specific antibodies and amplification system of estreptavidin-biotin peroxidase and diaminobenzidine were used. Syndecan-1 was uniformly expressed in basolateral membranes of normal epithelium, changing to a granular cytoplasmatic expression pattern in carcinomas. Syndecan-2 was observed mainly in a cytoplasmatic granular pattern, with high immunostaining intensity in areas of low Gleason score. E-cadherin was detected in basolateral membrane of normal epithelia showing decreased expression in high Gleason score samples. -Catenin was found in cell membranes of normal epithelia changing its distribution toward the nucleus and cytoplasm in carcinoma samples. We concluded that changes in expression and cell distribution of E-cadherin and -catenin correlated with the progression degree of prostate adenocarcinoma, suggesting a role of these molecules as markers of progression and prognosis. Furthermore, changes in the pattern expression of syndecan-1 and -2 indicate that both molecules may be involved in the EMT and tumor progression of prostate cancer.
Jornal de Pediatria, 2014
Objective: congenital adrenal hyperplasia (CAH) newborn screening can prevent neonatal mortality ... more Objective: congenital adrenal hyperplasia (CAH) newborn screening can prevent neonatal mortality in children with the salt-wasting form of the disease and prevent incorrect gender assignments, which can occur in females. However, the occurrence of false-positive results in preterm or low-birth-weight newborns creates some diagnostic difficulties, with consequent therapeutic implications. This study aimed to report the results of a pilot project for neonatal CAH screening conducted in the state of Minas Gerais, Brazil from 09/2007 to 05/2008 with a three-year follow-up. Methods: dried blood specimens were collected on filter paper cards three to seven days after birth of all newborns in the period. Samples were analyzed for 17-hydroxyprogesterone using an enzyme-linked immunosorbent assay (ELISA). Results: a total of 159,415 children were screened. The apparent incidence of the classic variant of the disease was 1:9,963, based on initial diagnoses following newborn screening. During the follow-up period, eight of 16 children initially diagnosed with CAH were reclassified as unaffected, resulting in a revised incidence of 1:19,927. The false-positive rate was 0.31%, and the positive predictive value was 2.1%. Sensitivity and specificity were 100% and 99.7%, respectively. Conclusions: newborn screening is an important public health policy in developing countries such as Brazil, where CAH remains underdiagnosed. It has great potential to identify children
Química Nova, 2003
Recebido em 1/4/02; aceito em 9/10/02 EVALUATION OF TESSIER, KELLER AND MILLER SEQUENTIAL EXTRACT... more Recebido em 1/4/02; aceito em 9/10/02 EVALUATION OF TESSIER, KELLER AND MILLER SEQUENTIAL EXTRACTION METHODS IN THE DETERMINATION OF NATIVE IRON IN THREE TYPES OF SOIL: HISTOSOL, OXISOL, AND MOLLISOL. Sequential extraction is not totally effective to dissolve distinct forms of trace elements. The extractive solution, for example, can dissolve less of the target fraction and more than another not wished fraction. The goal of this work is to compare the extraction of native iron with three sequential extraction methods of the heavy metals, using three soils with different physical chemistry characteristics: a histosol, an oxisol, and a mollisol. The results obtained in this work demonstrate that a smaller relation soil/extractor results in a larger extraction in almost all phases. The use of many stages of the sequential extraction, with the purpose of more association of the metal with different components of the soil, can result, among other things, in modification of the substratum by the action of the reagents used, besides reducing the selectivity of the more specific extractors. Readsorption and redistribution of the heavy metals could have happened with larger intensity in the fraction where hidroxilamine was used with higher temperature. Sequential extraction of iron, without enrichment of soil samples, in the respective fractions in each method, it was important to better understand the behavior of the reagents considered specific to each form of the metal in soil.
Química Nova, 2000
Recebido em 3/8/98; aceito em 16/4/99 ARSENIC SPECIATION-A REVIEW. This paper provides a review o... more Recebido em 3/8/98; aceito em 16/4/99 ARSENIC SPECIATION-A REVIEW. This paper provides a review on separation methods and analytical techniques for the determination of several species of organic and inorganic arsenic in different matrices. Arsenic is an element whose speciation is of particular interest due to the great variation of toxicity levels exhibited for its different chemical forms. Arsenic (III) and As (V) are the most toxic species while organic compounds such as arsenobetaine (AsB), produced by methylation of inorganics species (carcinogenics) are relatively less toxic, hence the great importance of arsenic speciation in the determination of the degree of contamination of an environmental or biological system.
Communications in Soil Science and Plant Analysis, 2001
Thirty-two soil samples from different locations of the Rio de Janeiro State, Brazil, were studie... more Thirty-two soil samples from different locations of the Rio de Janeiro State, Brazil, were studied in order to evaluate the amount of aluminum (Al) obtained by three extractants (1 M KCl, 1 M NH4OAc, 0.5 M CuCl2) and by the extraction of humic and fulvic acids (0.5 M ...
Archives of Disease in Childhood, 1983
Analytica Chimica Acta, 2000
An inexpensive microwave-assisted distillation procedure has been developed for quantitative dete... more An inexpensive microwave-assisted distillation procedure has been developed for quantitative determination of inorganic arsenic in soils by atomic fluorescence spectrometry (AFS). After reduction of As(V) to its trivalent state with potassium iodide, inorganic arsenic was distilled as AsCl 3 that was finally determined by atomic fluorescence after hydride generation with NaBH 4 in HCl medium. The different parameters that control the distillation: concentration and volume of HCl, time of distillation, sample weight, and oven load, were studied. The methodology developed has a detection limit of 0.015 g l −1 , which corresponds to a concentration of 0.006 g of As per gram of soil, and a relative standard deviation of 3% for nine independent analyses of the same soil sample containing 8.7 g g −1 As. The recovery percentage of As(III) and As(V) were 103 ± 4 and 106 ± 4%, respectively. Total arsenic was determined after microwave-assisted digestion, under pressure, with HCl : HNO 3 (3 : 1)/H 2 O 2 in hermetically sealed Teflon reactors. By introducing an additional microwave-assisted digestion step after distillation of inorganic arsenic, the organic fraction of arsenic in soils and sediments was established.
Urologic Oncology: Seminars and Original Investigations, 2010
The epithelial-mesenchymal transition (EMT) is considered a key step in tumor progression, where ... more The epithelial-mesenchymal transition (EMT) is considered a key step in tumor progression, where the invasive cancer cells change from epithelial to mesenchymal phenotype. During this process, a decrease or loss in adhesion molecules expression and an increase in migration molecules expression are observed. The aim of this work was to determine the expression and cellular distribution of syndecan-1 and -2 (migration molecules) and E-cadherin and beta-catenin (adhesion molecules) in different stages of prostate cancer progression. A quantitative immunohistochemical study of these molecules was carried out in tissue samples from benign prostatic hyperplasia and prostate carcinoma, with low and high Gleason score, obtained from biopsies archives of the Clinic Hospital of the University of Chile and Dipreca Hospital. Polyclonal specific antibodies and amplification system of estreptavidin-biotin peroxidase and diaminobenzidine were used. Syndecan-1 was uniformly expressed in basolateral membranes of normal epithelium, changing to a granular cytoplasmatic expression pattern in carcinomas. Syndecan-2 was observed mainly in a cytoplasmatic granular pattern, with high immunostaining intensity in areas of low Gleason score. E-cadherin was detected in basolateral membrane of normal epithelia showing decreased expression in high Gleason score samples. beta-Catenin was found in cell membranes of normal epithelia changing its distribution toward the nucleus and cytoplasm in carcinoma samples. We concluded that changes in expression and cell distribution of E-cadherin and beta-catenin correlated with the progression degree of prostate adenocarcinoma, suggesting a role of these molecules as markers of progression and prognosis. Furthermore, changes in the pattern expression of syndecan-1 and -2 indicate that both molecules may be involved in the EMT and tumor progression of prostate cancer.
Electroanalysis, 2001
A fast and sensitive voltammetric method for the determination of arsenite and total inorganic ar... more A fast and sensitive voltammetric method for the determination of arsenite and total inorganic arsenic in natural water systems is described using square-wave cathodic stripping voltammetry at a hanging mercury drop electrode. All the determinations were done in 1 M HCl, in the presence of 5 ppm copper(II) and dissolved oxygen. Discrimination between both oxidation states is achieved just by varying the composition of the supporting electrolyte: reduction of As(V) to As(III) is carried out at room temperature by a mixture of potassium iodide and ascorbic acid and inorganic arsenic determined as As(III) þ As(V), while As(III) is measured in the absence of the reducing agent. For an accumulation time of 60 s the detection limits were 0.7 ppb for As(III) in 1 M HCl, and 5 ppm Cu(II), 0.6 ppb for As(III) þ As(V) in 1 M HCl, 5 ppm Cu(II) and 0.04 % (w=v) KI þ 0.02 % (w=v) ascorbic acid. The precision, expressed as relative standard deviation (RSD) at 95 % confidence level, was calculated as 9 % from ten individual measurements taken at 2 ppb standard. The method was tested by the measurement of As(V) and As(III) in real and synthetic natural water samples.
Cadernos de Saúde Pública
Increasing attention is current focused on urban groundwater contamination with gasoline hydrocar... more Increasing attention is current focused on urban groundwater contamination with gasoline hydrocarbon compounds in Brazil. The compounds benzene, toluene, ethylbenzene, and xylenes (BTEX) contained in fuels are highly toxic and can have severe public health consequences, besides posing the risk of intake from the water table by way of contamination. After two years of a steady gasoline storage tank leak, water samples from private household wells in the district of Brisa Mar, Itaguaí, Rio de Janeiro State, were analyzed and the concentration of BTEX compounds was evaluated. Two out of ten water samples from the study area presented BTEX concentrations above the National Water Quality Standard (Brazilian Health Ministry Ruling No. 1469/2000), in which the maximum permissible benzene concentration is 5 micro g.L-1. Four others wells were also contaminated with nitrate, responsible for the induction of methemoglobinemia. Natural attenuation (intrinsic biodegradation) mechanisms through ...
Cadernos de Saúde Pública, 2002
A contaminação de águas subterrâneas por combustível derivado de petróleo tem sido objeto de cres... more A contaminação de águas subterrâneas por combustível derivado de petróleo tem sido objeto de crescente pesquisa no Brasil. Os compostos benzeno, tolueno, etilbenzeno e xilenos (BTEX), presentes nesses combustíveis, são extremamente tóxicos à saúde humana e podem inviabilizar a exploração de aqüíferos por eles contaminados. Neste trabalho, foi feita uma avaliação da qualidade da água de poço de algumas residências do Bairro Brisa Mar, Itaguaí, Rio de Janeiro, quanto à presença dos micropoluentes BTEX após dois anos da ocorrência de um vazamento de gasolina do tanque de armazenamento de combustível. Os resultados mostraram que dos dez poços avaliados, apenas dois encontram-se com valores de BTEX acima do recomendado pela Portaria 1.469/2000 do Ministério de Saúde, em que o teor máximo permitido para o benzeno é de 5µg.L-1. Em quatro poços há contaminação por nitrato, que é responsável pela indução da metemoglobinemia. Foram estudados também os possíveis mecanismos de atenuação natural...
Hormone Research in Paediatrics, 2015
Background: The same reference values for cortisol have been used for adults and children, but la... more Background: The same reference values for cortisol have been used for adults and children, but laboratory results obtained from an adult population might not be suitable for pediatric patients. Aims: To determine morning serum basal cortisol levels in children and adolescents. Methods: The study was conducted on 120 suitable reference individuals, healthy Brazilian children and adolescents from both genders aged 4-19 years old. The method used for cortisol assessment was the chemiluminescent enzyme immunoassay (VITROS® 5600 MicroWell; Johnson & Johnson, High Wycombe, UK, 2009), and the kit reference interval was 4.46-22.7 μg/dl (122.7-626.2 nmol/l). The setting limits were calculated according to the Clinical Laboratory Standards Institute guidelines. Results: The morning serum basal cortisol levels increased with age and pubertal maturation, but there were no differences based on gender. The cortisol reference values were established based on the 2.5th and 97.5th percentiles as 2.9...
Urologic Oncology: Seminars and Original Investigations, 2010
The epithelial-mesenchymal transition (EMT) is considered a key step in tumor progression, where ... more The epithelial-mesenchymal transition (EMT) is considered a key step in tumor progression, where the invasive cancer cells change from epithelial to mesenchymal phenotype. During this process, a decrease or loss in adhesion molecules expression and an increase in migration molecules expression are observed. The aim of this work was to determine the expression and cellular distribution of syndecan-1 and -2 (migration molecules) and E-cadherin and -catenin (adhesion molecules) in different stages of prostate cancer progression. A quantitative immunohistochemical study of these molecules was carried out in tissue samples from benign prostatic hyperplasia and prostate carcinoma, with low and high Gleason score, obtained from biopsies archives of the Clinic Hospital of the University of Chile and Dipreca Hospital. Polyclonal specific antibodies and amplification system of estreptavidin-biotin peroxidase and diaminobenzidine were used. Syndecan-1 was uniformly expressed in basolateral membranes of normal epithelium, changing to a granular cytoplasmatic expression pattern in carcinomas. Syndecan-2 was observed mainly in a cytoplasmatic granular pattern, with high immunostaining intensity in areas of low Gleason score. E-cadherin was detected in basolateral membrane of normal epithelia showing decreased expression in high Gleason score samples. -Catenin was found in cell membranes of normal epithelia changing its distribution toward the nucleus and cytoplasm in carcinoma samples. We concluded that changes in expression and cell distribution of E-cadherin and -catenin correlated with the progression degree of prostate adenocarcinoma, suggesting a role of these molecules as markers of progression and prognosis. Furthermore, changes in the pattern expression of syndecan-1 and -2 indicate that both molecules may be involved in the EMT and tumor progression of prostate cancer.
Jornal de Pediatria, 2014
Objective: congenital adrenal hyperplasia (CAH) newborn screening can prevent neonatal mortality ... more Objective: congenital adrenal hyperplasia (CAH) newborn screening can prevent neonatal mortality in children with the salt-wasting form of the disease and prevent incorrect gender assignments, which can occur in females. However, the occurrence of false-positive results in preterm or low-birth-weight newborns creates some diagnostic difficulties, with consequent therapeutic implications. This study aimed to report the results of a pilot project for neonatal CAH screening conducted in the state of Minas Gerais, Brazil from 09/2007 to 05/2008 with a three-year follow-up. Methods: dried blood specimens were collected on filter paper cards three to seven days after birth of all newborns in the period. Samples were analyzed for 17-hydroxyprogesterone using an enzyme-linked immunosorbent assay (ELISA). Results: a total of 159,415 children were screened. The apparent incidence of the classic variant of the disease was 1:9,963, based on initial diagnoses following newborn screening. During the follow-up period, eight of 16 children initially diagnosed with CAH were reclassified as unaffected, resulting in a revised incidence of 1:19,927. The false-positive rate was 0.31%, and the positive predictive value was 2.1%. Sensitivity and specificity were 100% and 99.7%, respectively. Conclusions: newborn screening is an important public health policy in developing countries such as Brazil, where CAH remains underdiagnosed. It has great potential to identify children
Química Nova, 2003
Recebido em 1/4/02; aceito em 9/10/02 EVALUATION OF TESSIER, KELLER AND MILLER SEQUENTIAL EXTRACT... more Recebido em 1/4/02; aceito em 9/10/02 EVALUATION OF TESSIER, KELLER AND MILLER SEQUENTIAL EXTRACTION METHODS IN THE DETERMINATION OF NATIVE IRON IN THREE TYPES OF SOIL: HISTOSOL, OXISOL, AND MOLLISOL. Sequential extraction is not totally effective to dissolve distinct forms of trace elements. The extractive solution, for example, can dissolve less of the target fraction and more than another not wished fraction. The goal of this work is to compare the extraction of native iron with three sequential extraction methods of the heavy metals, using three soils with different physical chemistry characteristics: a histosol, an oxisol, and a mollisol. The results obtained in this work demonstrate that a smaller relation soil/extractor results in a larger extraction in almost all phases. The use of many stages of the sequential extraction, with the purpose of more association of the metal with different components of the soil, can result, among other things, in modification of the substratum by the action of the reagents used, besides reducing the selectivity of the more specific extractors. Readsorption and redistribution of the heavy metals could have happened with larger intensity in the fraction where hidroxilamine was used with higher temperature. Sequential extraction of iron, without enrichment of soil samples, in the respective fractions in each method, it was important to better understand the behavior of the reagents considered specific to each form of the metal in soil.
Química Nova, 2000
Recebido em 3/8/98; aceito em 16/4/99 ARSENIC SPECIATION-A REVIEW. This paper provides a review o... more Recebido em 3/8/98; aceito em 16/4/99 ARSENIC SPECIATION-A REVIEW. This paper provides a review on separation methods and analytical techniques for the determination of several species of organic and inorganic arsenic in different matrices. Arsenic is an element whose speciation is of particular interest due to the great variation of toxicity levels exhibited for its different chemical forms. Arsenic (III) and As (V) are the most toxic species while organic compounds such as arsenobetaine (AsB), produced by methylation of inorganics species (carcinogenics) are relatively less toxic, hence the great importance of arsenic speciation in the determination of the degree of contamination of an environmental or biological system.
Communications in Soil Science and Plant Analysis, 2001
Thirty-two soil samples from different locations of the Rio de Janeiro State, Brazil, were studie... more Thirty-two soil samples from different locations of the Rio de Janeiro State, Brazil, were studied in order to evaluate the amount of aluminum (Al) obtained by three extractants (1 M KCl, 1 M NH4OAc, 0.5 M CuCl2) and by the extraction of humic and fulvic acids (0.5 M ...
Archives of Disease in Childhood, 1983
Analytica Chimica Acta, 2000
An inexpensive microwave-assisted distillation procedure has been developed for quantitative dete... more An inexpensive microwave-assisted distillation procedure has been developed for quantitative determination of inorganic arsenic in soils by atomic fluorescence spectrometry (AFS). After reduction of As(V) to its trivalent state with potassium iodide, inorganic arsenic was distilled as AsCl 3 that was finally determined by atomic fluorescence after hydride generation with NaBH 4 in HCl medium. The different parameters that control the distillation: concentration and volume of HCl, time of distillation, sample weight, and oven load, were studied. The methodology developed has a detection limit of 0.015 g l −1 , which corresponds to a concentration of 0.006 g of As per gram of soil, and a relative standard deviation of 3% for nine independent analyses of the same soil sample containing 8.7 g g −1 As. The recovery percentage of As(III) and As(V) were 103 ± 4 and 106 ± 4%, respectively. Total arsenic was determined after microwave-assisted digestion, under pressure, with HCl : HNO 3 (3 : 1)/H 2 O 2 in hermetically sealed Teflon reactors. By introducing an additional microwave-assisted digestion step after distillation of inorganic arsenic, the organic fraction of arsenic in soils and sediments was established.