Desorption electrospray ionization mass spectrometry (DESI-MS) applied to the speciation of arsenic compounds from fern leaves.

The different chemical forms of arsenic compounds, including inorganic and organic species, present distinct environmental impacts and toxicities. Desorption electrospray ionization mass spectrometry (DESI-MS) is an excellent technique for in situ analysis, as it operates under atmospheric pressure and room temperature and is conducted with no/minimal sample pretreatment. Aimed at expanding its scope, DESI-MS is applied herein for the quick and reliable detection of inorganic (arsenate--As(V): AsO4(3-) and arsenite--As(III): AsO2(-)) and organic (dimethylarsinic acid--DMA: (CH3)2AsO(OH) and disodium methyl arsonate hexahydrate: CH3AsO3·2Na·6H2O) arsenic compounds in fern leaves. Operational conditions of DESI-MS were optimized with DMA standard deposited on paper surfaces to improve ionization efficiency and detection limits. Mass spectra data for all arsenic species were acquired in both the positive and negative ion modes. The positive ion mode was shown to be useful in detecting both the organic and inorganic arsenic compounds. The negative ion mode was shown only to be useful in detecting As(V) species. Moreover, MS/MS spectra were recorded to confirm the identity of each arsenic compound by the characteristic fragmentation profiles. Optimized conditions of DESI-MS were applied to the analysis of fern leaves. LC-ICP-MS was employed to confirm the results obtained by DESI-MS and to quantify the arsenic species in fern leaves. The results confirmed the applicability of DESI-MS in detecting arsenic compounds in complex matrices.

Chemical phosphorus removal: a clean strategy for piggery wastewater management in Brazil.

The intensive production of animal protein is known to be an environmental polluting activity, especially if the wastewater produced is not managed properly. Swine production in Brazil is growing, and technologies to manage all pollutants present in the wastewater effluent are needed. This work presents a case of study of phosphorus (P) removal from piggery wastewater using Ca(OH)2, and demonstrates the feasibility of this strategy for P management. The effluent of a swine manure treatment plant was treated with Ca(OH)2. According to the addition of Ca(OH)2 the pH of the effluent ranged from 8.0 to 10.0. Different conditions of sludge dewatering were evaluated, and the chemical composition of sludge was investigated. Ion chromatography analysis of effluent samples showed that 92% of total P (TP) was present as soluble P (SP) whereas 75% of SP species were present as phosphate. The efficiency of P removal was typically 90% at pH 8.5 and higher than 98% at pH 10.5. The sludge was separated by sedimentation, centrifugation or filtration and dried. The TP content of dried sludge was 9.3% (w/w). X-ray diffraction analysis of the dry sludge showed the presence of amorphous compounds of Ca and P, which is an indication that the sludge obtained from the swine manure treatment has a potential for application as biofertilizer.

Fast digestion procedure for determination of catalyst residues in La- and Ni-based carbon nanotubes.

A procedure based on microwave-induced combustion (MIC) was applied for carbon nanotube (CNT) digestion and further determination of La and Ni by inductively coupled plasma optical emission spectrometry (ICP OES). Samples (up to 400 mg) were completely combusted at 20 bar of oxygen, and a reflux step was applied to improve the analyte absorption. Combustion was finished in less than 50 s, and analytes were absorbed in diluted acid solution. Absorbing solutions ranging from 1 to 12 mol L(-1) for HCl and from 1 to 14 mol L(-1) HNO(3) were tested. Accuracy for both analytes was evaluated using certified reference materials and analyte spikes. Neutron activation analysis was also used to check accuracy for La. Agreement was better than 96% for La and Ni using a 4 mol L(-1) absorbing solution of HNO(3) or HCl and 15 min of reflux. The residual carbon content was lower than 0.5%. Up to eight samples could be digested simultaneously in 36 min, that makes the throughput using MIC more suitable when it is compared to the digestion by dry ashing as recommended by other procedures. The obtained limits of detection using MIC were lower than those using dry ashing, and a single absorbing solution, e.g., diluted HNO(3), can be used for simultaneous determination of La and Ni by ICP OES.

Arsenic speciation analysis in rice milk using LC-ICP-MS.

The consumption of rice milk has increased, mainly by individuals intolerant to lactose or allergic to cow milk. However, rice milk contains As. In this sense, the concentration of As in rice milk should be controlled. In the present study it is proposed a methodology for determination of As(III), dimethylarsenic (DMA), monomethylarsenic (MMA) and As(V) species in rice milk using LC-ICP-MS. The main features of the methodology are fast analysis, easy and simple sample preparation, where the sample is 3-fold diluted in the mobile phase and then filtered. The four arsenic species investigated were detected in the analysed samples, being As(V) the main species. The limit of quantification of the method ranges from 0.25 to 0.43 µg L-1 As. The analyte recovery ranged from 81 to 116% for samples spiked to 1.00 µg L-1 or 5.00 µg L-1 As and the relative standard deviation was better than 5%.

Encapsulation of Lactobacillus acidophilus and different prebiotic agents by external ionic gelation followed by freeze-drying / Encapsulação de Lactobacillus acidophilus e diferentes agentes prebióticos por gelificação iônica externa seguida de liofilização

ABSTRACT: The aim of this study was to investigate the influence of the addition of prebiotics rice bran, inulin and hi-maize, on the survival of Lactobacillus acidophilus in alginate microparticles obtained by external ionic gelation followed by freeze-drying. The microparticles size ranged from 127.5μm to 234.6μm. Microparticles added from the different prebiotics demonstrated an increase in the protection of the microorganism, which presented greater viability against the gastrointestinal simulation. As for storage under different conditions, rice bran treatment at 25ºC kept probiotics viable for 30 days. Under storage conditions -18°C and 7°C, treatments containing prebiotics hi-maize and rice bran maintained viable probiotic microorganisms for a period of 60 days.

RESUMO: O objetivo desse estudo foi investigar a influência da adição dos prebióticos farelo de arroz, inulina e hi-maize, na sobrevivência de Lactobacillus acidophilus em micropartículas de alginato obtidas por gelificação externa seguida de liofilização. Analisou-se o tamanho das micropartículas, a viabilidade, em simulação gastrointestinal e estabilidade, durante armazenamento. O tamanho das micropartículas variou de 127.5µm a 234.6µm. As micropartículas adicionadas dos diferentes prebióticos demonstraram um aumento na proteção do microrganismo, que apresentou maior viabilidade frente à simulação gastrointestinal. Quanto ao armazenamento em diferentes condições, a 25ºC o tratamento farelo de arroz manteve os probióticos viáveis por 30 dias. Nas condições de armazenamento -18ºC e 7°C os tratamentos contendo os prebióticoshi-maize e farelo de arroz mantiveram os microrganismos probióticos viáveis por um período de 60 dias.

Development, characterization and viability study of probiotic microcapsules produced by complex coacervation followed by freeze-drying / Desenvolvimento, caracterização e estudo da viabilidade de microcápsulas probióticas produzidas por coacervação complexa seguida de liofilização

ABSTRACT: Technique of complex coacervation was used to produce microcapsules of Lactobacillus acidophilus La-5 encapsulated in gelatin and gum arabic which were then freeze-drying. Microcapsules were characterized using scanning electron and optical microscopy, and resistance of probiotics was evaluated during release into a simulated gastrointestinal tract and storage at different temperatures. The complex coacervation process produced microcapsules with a high encapsulation efficiency (77.60% and 87.53%), ranging from 127.14-227.05 μm with uniform distribution. Microencapsulation was an efficient approach to achieve significant protection of probiotics against simulated gastrointestinal conditions compared with free cells. Encapsulation also improved the viability of probiotics during storage at either −18 ºC for 120 days, 7 ºC for 105 days or 25 ºC for 45 days. Therefore, complex coacervation was demonstrated to be adequate and promising for encapsulation of probiotics.

RESUMO: A técnica de coacervação complexa foi utilizada para a produção de microcápsulas contendo Lactobacillus acidophilus La-5 em gelatina e goma arábica seguida de secagem por liofilização. As microcápsulas foram caracterizadas por microscopia óptica e eletrônica de varredura, assim como a resistência dos probióticos frente à liberação "in vitro" ao trato gastrointestinal simulado e ao armazenamento em diferentes condições de temperatura também foram avaliados. O processo de coacervação complexa formou microcápsulas com alta eficiência de encapsulação (77,60% e 87,53%), tamanho compreendido entre 127,14 e 227,05 µm e distribuição uniforme. As microcápsulas foram eficientes em promover a proteção substancial dos probióticos frente às condições gastrointestinais simuladas, em comparação às células livres. A encapsulação também foi eficiente em manter a viabilidade dos probióticos durante o armazenamento em temperaturas de −18 ºC por 120 dias, 7 ºC por 105 dias e 25 ºC por 45 dias. Dessa forma, a coacervação complexa se mostra adequada e promissora para a encapsulação dos probióticos.

Drosophila melanogaster - an embryonic model for studying behavioral and biochemical effects of manganese exposure.

Embryonic animals are especially susceptible to metal exposure. Manganese (Mn) is an essential element, but in excess it can induce toxicity. In this study we used Drosophila melanogaster as an embryonic model to investigate biochemical and behavioral alterations due to Mn exposure. Flies were treated with standard medium supplemented with MnCl2 at 0.1 mM, 0.5 mM or 1 mM from the egg to the adult stage. At 0.5 mM and 1 mM Mn, newly ecloded flies showed significantly enhanced locomotor activity when assessed by negative geotaxis behavior. In addition, a significant increase in Mn levels (p < 0.0001) was observed, while Ca, Fe, Cu, Zn and S levels were significantly decreased. A significant drop in cell viability occurred in flies exposed to 1 mM Mn. There was also an induction of reactive oxygen species at 0.5 mM and 1 mM Mn (p < 0.05). At 1 mM, Mn increased Catalase (p < 0.005), Superoxide Dismutase (p < 0.005) and Hsp83 (p < 0.0001) mRNA expression, without altering Catalase or Superoxide Dismutase activity; the activity of Thioredoxin reductase and Glutatione-S-transferase enzymes was increased. Mn treatment did not alter ERK or JNK1/2 phosphorylation, but at 1 mM caused an inhibition of p38(MAPK) phosphorylation. Together these data suggest mechanisms of adaptation in the fly response to Mn exposure in embryonic life.

Simultaneous diffuse reflectance infrared determination of clavulanic acid and amoxicillin using multivariate calibration techniques.

A method for simultaneous determination of clavulanic acid (CA) and amoxicillin (AMO) in commercial tablets was developed using diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and multivariate calibration. Twenty-five samples (10 commercial and 15 synthetic) were used as a calibration set and 15 samples (10 commercial and 5 synthetic) were used for a prediction set. Calibration models were developed using partial least squares (PLS), interval PLS (iPLS), and synergy interval PLS (siPLS) algorithms. The best algorithm for CA determination was siPLS model with spectra divided in 30 intervals and combinations of 2 intervals. This model showed a root mean square error of prediction (RMSEP) of 5.1 mg g(-1). For AMO determination, the best siPLS model was obtained with spectra divided in 10 intervals and combinations of 4 intervals. This model showed a RMSEP of 22.3 mg g(-1). The proposed method was considered as a suitable for the simultaneous determination of CA and AMO in commercial pharmaceuticals products.

In vitro ZnCl2 cytotoxicity and genotoxicity in human leukocytes: Zero-order kinetic cellular zinc influx / Citotoxicidade e genotoxicidade do ZnCl2 em leucócitos humanos in vitro: influx cellular de zinco com cinética de ordem zero

Zinc (Zn) is an essential trace element for cellular viability, but concentrations above physiologic level may lead to cellular damage. The purpose of the present study was to evaluate the in vitro ZnCl2 genotoxicity and cytotoxicity in human leukocyte cells. This was assessed in an unprecedented way that correlated the level of intracellular Zn after cell exposition with the cellular damage. The exposure to increased Zn concentrations (2.5-20 µg mL-1), showed significantly reduced cellular leukocyte viability. However, significant DNA damages were observed only when the Zn exposure concentrations were from 10-20 µg mL-1. The Zn intracellular levels found in leukocytes was from 72.25-268.9 ρ g cell-1, starting to induce cytotoxicity and genotoxicity at concentrations of 95.68 and 126.2 ρg cell-1, respectively. The relationship between the exposure concentration and intracellular levels of Zn suggests that the influx of Zn, in the form of ZnCl2, occurs in human leukocytes under zero-order kinetics.

O Zinco (Zn) é um elemento traço essencial para a viabilidade celular, mas em concentrações acima dos níveis fisiológicos pode conduzir a danos celulares. A proposta do presente estudo foi avaliar a citotoxicidade e genotoxicidade do ZnCl2 em leucócitos humanos in vitro. De maneira sem precedentes, foi acessado o nível de Zn intracelular após exposição e relacionado com o nível de dano celular. A exposição a crescentes concentrações de Zn (2,5-20 µg mL-1), mostraram significante redução da viabilidade celular dos leucócitos. Entretanto, danos significativos ao DNA foram encontrados somente a partir das concentrações de exposição ao Zn de 10-20 µg mL-1. Os níveis intracelulares de Zn encontrados nos leucócitos foram de 72,25-268,9 ρg célula-1, começando a induzir citotoxicidade e genotoxicidade nas concentrações de 95,68 and 126,2 ρg célula-1, respectivamente. A relação entre a concentração de exposição e os níveis intracelulares de Zn sugerem que o influxo de Zn, sob a forma de ZnCl2, ocorre em cinética de ordem zero em leucócitos humanos.

Casca de ovo como fonte de cálcio para humanos: composição mineral e análise microbiológica / Eggshell as calcium source for humans: mineral composition and microbiological analysis

Este estudo teve como objetivo avaliar a composição mineral de diferentes tipos de cascas de ovo, bem como a segurança microbiológica de amostras submetidas a diferentes métodos de higienização. Para a obtenção do pó de casca de ovo, as cascas foram lavadas, higienizadas, secas em estufa e trituradas em moinho. Cascas de ovo de granja (criação confinada), de coloração branca e vermelha, e cascas de ovo coloniais (caipira), provenientes da região central do Rio Grande do Sul, foram comparadas quanto a sua composição mineral. O Ca, mineral predominante na casca de ovo, se manteve em concentrações semelhantes nas diferentes amostras (cerca de 365mg g-1). As cascas de ovo de granja apresentaram maior concentração de Mg e menor concentração de Sr que as cascas de ovo coloniais. Não foram encontradas quantidades significativas de Fe, Cr, Mn, Mo, Ni, Se, Al, Cd e Pb nas amostras analisadas. Adicionalmente, tanto amostras higienizadas com imersão em hipoclorito e posterior fervura em água, quanto amostras nas quais a imersão em hipoclorito foi suprimida, não apresentaram contaminação por coliformes, estafilococos ou salmonela. Os resultados indicam que a casca de ovo pode ser utilizada na nutrição humana, já que é rica em Ca, não apresenta contaminação por metais tóxicos e, se processada de forma adequada, apresenta boa qualidade higiênico-sanitária.

This study aimed to evaluate the mineral composition of different kinds of eggshell, as well as the microbiological safety of samples submitted to different sanitization procedures. To obtain the eggshell powder, the shells were washed, sanitized, oven dried and grinded in a mill. White- and brown-colored eggshells from confined laying hens and eggshells from free-ranged laying hens from the central region of Rio Grande do Sul were compared for their mineral composition. Ca, the predominant mineral in eggshells, remained at similar concentrations in the different samples (approximately 365mg g-1). Eggshells from confined laying hens had higher Mg concentration and lower Sr concentration than the shells from free-ranged laying hens. No significant amounts of Fe, Cr, Mn, Mo, Ni, Se, Al, Cd or Pb were found in the samples. Additionally, both samples that were sanitized by immersion in hypochlorite and subsequently boiled in water as well as samples in which hypochlorite immersion was suppressed did not show coliform, staphylococcus or salmonella contamination. The results indicate that eggshell can be used in human nutrition since it is rich Ca source, shows no contamination by toxic metals and has good sanitary quality when properly processed.

Effect of antioxidant potential on severity of cirrhosis in humans / Efecto del potencial antioxidante para las complicaciones de la cirrosis en los seres humanos

Background/Aims: to examine the relationship between the antioxidant potential and severity parameters of cirrhosis in humans. Methods: fifteen patients with hepatic cirrhosis (nine subjects - Child group B, and six subjects - Child group C) and nine control subjects were enrolled in the study. The main criteria taken into account to characterize the diagnosis of cirrhosis and its complications were the AST: ALT ratio, AST to platelet ratio index, Bonacini score, Meld score and Child classification. Those parameters were determined based on laboratory results and patient’s clinical records. Se, Zn, ascorbic acid (AA) levels and oxidative stress parameters were measured in blood samples of cirrhotic patients. Results: the analysis of plasma levels of Se and AA showed low concentrations in cirrhotic patients compared with control subjects (P < 0.05). Though, there was a positive correlation between plasma of Se and severity parameters of cirrhosis in patients of Child group B and C. In the activity of the antioxidant enzymes only catalase was lower in patients of Child group C compared with control group. Conclusion: we found low plasma levels of Se and AA among cirrhotic patients. However, is not clear why selenium levels tend to increase with the severity of liver cirrhosis (AU)

Introducción/Objetivos: examinar la relación entre los potenciales antioxidantes y los parámetros de gravedad de la cirrosis en los seres humanos. Métodos: quince pacientes con cirrosis hepática (nueve sujetos - grupo Child B, y seis sujetos - grupo Child C) y nueve sujetos control fueron incluidos en el estudio. Los principales criterios que se tuvieron en cuenta para caracterizar el diagnóstico de la cirrosis y sus complicaciones fueron la AST: relación de ALT, AST índice de la relación de plaquetas, clasificación Bonacini, clasificación MELD y clasificación de Child. Estos parámetros fueron determinados con base en los resultados de laboratorio y los registros clínicos del paciente. Se midieron los niveles de Zn, ácido ascórbico (AA) y los parámetros de estrés oxidativo en muestras de sangre de pacientes cirróticos. Resultados: el análisis de los niveles plasmáticos de Se y AA mostraron bajas concentraciones en los pacientes cirróticos en comparación con los sujetos control (P < 0,05); sin embargo, hubo una correlación positiva entre el plasma de Se y los parámetros de gravedad de la cirrosis en pacientes del grupo Child B y C. En la actividad de las enzimas antioxidantes catalasa solamente fue menor en los pacientes del grupo Child C, en comparación con el grupo control. Conclusión: se encontraron niveles bajos en plasma de Se y AA en pacientes cirróticos. Sin embargo, no está claro por qué los niveles de selenio tienden a aumentar con la gravedad de la cirrosis hepática (AU)

Cadmium and mineral nutrient accumulation in potato plantlets grown under cadmium stress in two different experimental culture conditions.

In order to evaluate the effect of cadmium (Cd(2+)) toxicity on mineral nutrient accumulation in potato (Solanum tuberosum L.), two cultivars named Asterix and Macaca were cultivated both in vitro and in hydroponic experiments under increasing levels of Cd(2+) (0, 100, 200, 300, 400 and 500 microM in vitro and 0, 50, 100, 150 and 200 microM in hydroponic culture). At 22 and 7 days of exposure to Cd(2+), for the in vitro and hydroponic experiment, respectively, the plantlets were separated into roots and shoot, which were analyzed for biomass as well as Cd(2+), and macro (Ca(2+), K(+) and Mg(2+)) and micronutrient (Cu(2+), Fe(2+), Mn(2+) and Zn(2+)) contents. In the hydroponic experiment, there was no reduction in shoot and root dry weight for any Cd(2+) level, regardless of the potato cultivar. In contrast, in the in vitro experiment, there was an increase in biomass at low Cd(2+) levels, while higher Cd(2+) levels caused a decrease. In general, Cd(2+) decreased the macronutrient and micronutrient contents in the in vitro cultured plantlets in both roots and shoot of cultivars. In contrast, the macronutrient and micronutrient contents in the hydroponically grown plantlets were generally not affected by Cd(2+). Our data suggest that the influence of Cd(2+) on nutrient content in potato was related to the level of Cd(2+) in the substrate, potato cultivar, plant organ, essential element, growth medium and exposure time.

Chemical composition and antibacterial activity of Aloysia triphylla (L'Hérit) Britton extracts obtained by pressurized CO2 extraction

This study investigated the chemical composition of five different extracts of Aloysia triphylla and their activity against Aeromonas sp. The extracts were obtained from the dried leaves by pressurized CO2 extraction at 30, 50 and 70ºC, and 100, 150, and 200 bar, and analyzed by GC/FID and GC-MS. The antibacterial activity was assayed by the microdilution method. The tested microorganisms comprised seven Aeromonas isolates obtained from the kidney of infected silver catfish, Rhamdia quelen. The yield, chemical composition and antibacterial activity of the extracts were dependent on the extraction conditions. Mono and sesquiterpenoids were the major constituents of all the extracts and the highest extraction yield was obtained at 70ºC and 200 bar. A. triphylla presented moderate antibacterial activity against Aeromonas sp.

Teores totais de metais pesados no solo após aplicação de dejeto líquido de suínos / Total content of heavy metals in the soil after pig slurry application

A utilização de lavoura e pastagens tem sido uma importante senão a principal alternativa de descarte do dejeto líquido de suínos. Porém, seu uso, muitas vezes, tem sido feito em quantidades superiores às exigências das culturas e com aplicações sequenciais que podem potencializar o efeito poluidor desse resíduo, já que o solo tem uma capacidade limitada de suporte. O presente estudo teve por objetivo determinar os teores totais de zinco (Zn), cobre (Cu), cromo (Cr), níquel (Ni), manganês (Mn) e cádmio (Cd) em áreas que são usadas como local de descarte de dejeto líquido de suínos. Para isso, foram coletadas amostras de solo em 13 propriedades rurais da região Oeste de Santa Catarina, usadas anualmente como local de descarte, e que possuíam um histórico de aplicação desse resíduo de 4 a 22 anos. Além disso, foi também realizada amostragem de solo em um experimento no município de Paraíso do Sul, RS, sob pastagem natural, que, durante um período de cinco anos, recebeu 28 aplicações de dejeto líquido de suínos. Zinco e cobre são os elementos que mais devem merecer a atenção com relação a um possível acúmulo no solo, em áreas com aplicação de dejeto líquido de suínos.

The use of crop and pasture has been an important if not the main alternative of pig slurry disposal. However, its use has often been made in quantities exceeding the requirements of crops and with sequential applications that can enhance the polluting effect of this waste once the soil has a limited capacity of support. The present study aimed to determine the total content of zinc (Zn), copper (Cu), chromium (Cr), nickel (Ni), manganese (Mn) and cadmium (Cd) in areas that are used as a disposal site of pig slurry. For this, there were collected soil samples in 13 farms in the West Region of Santa Catarina used annually as a disposal site, and which had a history of application of the residue from 4 to 22 years. In addition, it was also conducted soil sampling in an experiment in the municipality of Paraíso do Sul, RS under natural pasture, that during five years received 28 applications of pig slurry. Zinc and copper are the elements that deserve more attention in relation to a possible accumulation in the soil, in areas with application of pig slurry.

Chromium determination in pharmaceutical grade barium sulfate by solid sampling electrothermal atomic absorption spectrometry with Zeeman-effect background correction.

A procedure for chromium (Cr) determination in pharmaceutical grade barium sulfate by direct solid sampling electrothermal atomic absorption spectrometry (DSS-ET AAS) with Zeeman-effect background correction was developed. Operational conditions for the proposed procedure and the use of citric acid, ammonium phosphate, palladium and magnesium nitrate as chemical modifiers were evaluated. Pyrolysis and atomization temperatures were set at 1500 and 2400 degrees C, respectively and the use of matrix modifiers did not improve these conditions. Graphite platform presented high degradation rate, but minima changes were observed in the sensitivity or signal profile. Samples (0.3-1 mg) were weighted and introduced into the furnace using a manual solid sampling system. The linear concentration range of the calibration curve was from 100 to 1800 pg (R(2)>0.995). The characteristic mass was 7.7 pg and the limit of detection was 2.4 pg. Chromium concentration in commercial samples ranged from 0.45 to 1.06 microg g(-1) and these results were confirmed by standard addition method. The mean reproducibility was 12% (n=20 in a 3-day period) and repeatability was less than 9%. Results obtained using inductively coupled plasma optical emission spectrometry and conventional electrothermal atomic absorption spectrometry after extraction with HNO3 were around 20% lower than those obtained by the proposed procedure. It was assumed that the low results were due to incomplete extraction even using hard conditions related to temperature and pressure. The proposed procedure by DSS-ET AAS provided some advantages related to recommended pharmacopoeias methodology, as lower risks of contamination and analyte losses, higher specificity, accuracy and sensitivity, no toxic or unstable reagents are required, and calibration with aqueous standards was feasible.

Microwave-assisted sample combustion: a technique for sample preparation in trace element determination.

A novel digestion procedure based on sample combustion ignited by microwave radiation is proposed for organic samples. Certified samples of bovine liver, pig kidney, and skim milk were used as examples to demonstrate the performance of the proposed procedure. Cadmium and copper were determined in these samples by electrothermal atomic absorption spectrometry. Samples (between 50 and 250 mg) were wrapped with paper and placed on a homemade quartz holder that was positioned inside to quartz vessels used in a commercial microwave oven. Ammonium nitrate solution was added to the paper, and vessels were pressurized with oxygen to 15 bar. The rotor containing four vessels was placed inside the oven, and microwave radiation was applied for 20 s at 1400 W. Combustion was complete in few seconds, and an additional reflux step, which was optional, was applied. The agreement to the certified values was between 96 and 105% for both analytes. Only with the combustion step, the residual carbon (RC) was below 1.3%. The RC decreased to less than 0.4% when an additional reflux step with concentrated nitric acid was applied.

High frequency of skin reactions in patients with leishmaniasis treated with meglumine antimoniate contaminated with heavy metals. A comparative approach using historical controls

We analyzed data from historical controls treated with meglumine antimoniate to compare the frequency of adverse events observed in patients with cutaneous leishmaniasis treated with the same dose of meglumine antimoniate contaminated with heavy metals in an endemic area of the State of Bahia, Brazil. Group A patients were treated in 2000 with the drug produced by Eurofarma Laboratórios Ltda., São Paulo, Brazil (lot A) and group B patients were treated in 1996 with the reference drug produced by Rhodia Farma Ltda., São Paulo, Brazil (lot B). We observed an unusual higher frequency of skin reactions in group A patients. However, all type of adverse events observed in group A were also observed in group B. The physico-chemical analysis of these lots revealed that lot A had lower pH and higher concentration of total and trivalent antimony, lead, cadmium, and arsenic. Our findings suggest that the skin reactions could be attributed to heavy metal contamination of lot A