Risk assessment of the occurrence of aflatoxin and fungi in peanuts and cashew nuts

In the present study, the occurrence of fungi and aflatoxins (AFs) in peanut and cashew nut samples was investigated. Mycological analysis revealed the presence of fungi in 58.8% of samples, and assessment of AFs by chromatographic methods revealed that 52.9% were contaminated by AFs. AFB1 was the principal component in all AF-contaminated samples, with a mean level of 14.0, and 1.08 µg/kg in peanut and cashew nut, respectively. Eleven samples (32.4%) exceeded the total AF maximum level (4 µg/kg) and 8 samples (23.5%) exceeded the AFB1 (2 µg/kg) established by the European Commission. Our findings suggest that the incidence of AFs emphasizes the need for regular monitoring and a more stringent food safety system to control AFs at the lowest possible levels in peanuts and cashew nuts. The hypothetical dietary exposure suggests that the food products evaluated may significantly contribute to the overall human exposure

QuEChERS-HPLC-DAD method for sulphonamides in chicken breast

The development of a QuEChERS-HPLC-DAD method using a Lichrospher 60 RP-Select B column (250 x 4.6 mm x 5 µm) at 40ºC, mobile phase constituted by phosphate buffer:acetonitrile (75:25, v/v) at a initial flow rate of 0.5 mL min-1, increased by 1.2 mL min-1 and at 265 nm is presented for simultaneous determination of sulphadiazine, sulphametoxipiridazine and sulphamethoxazole in chicken breast samples. QuEchERS is inexpensive, fast and easy, and the extraction of the analytes of the matrix was successfully employed. In addition, the method presented linearity, in the range of 25, 50, 100, 150, 175, and 200 µg kg-1, precision, selectivity and sensitivity. The intraday precision (RSD %) for QuEChERS method was between 3.6-10.8 (SDZ), 6.9-14.1 (SPZ) and 1.9-10.9 (SMX) and interday precision (RSD%) was between 1.5-9.7, 1.7-4.1 and 2.1-10.2, respectively. Results of accuracy (bias) were in the range of -8.6 to +11.9 %. Therefore, the validated method is clearly useful for the practical residue monitoring of the drugs evaluated in chicken samples, as all the values were within the acceptable criteria used for food safety. Of 6 samples analyzed, none of them showed contamination of the sulphonamides studied at detectable levels.

O desenvolvimento de um método QuEChERS-HPLC-DAD usando uma coluna Lichrospher RP-60 Select B (250 x 4,6 mm x 5 µm) a 40 ºC, fase móvel constituída por tampão de fosfato: acetonitrila (75:25, v/v) a uma vazão inicial de 0,5 mL min-1, aumentando 1,2 mL min-1 e a 265 nm é apresentado para a determinação simultânea de sulfadiazina, sulfametoxipiridazina e sulfametoxazol em amostras de peito de frango. O QuEChERS é barato, rápido e fácil, e a extração dos analitos da matriz foi empregada com sucesso. Além disso, o método apresentou linearidade, na faixa de 25, 50, 100, 150, 175 e 200 µg kg-1, precisão, seletividade e sensibilidade. A precisão intradia (RSD %) para o método QuEChERS foi entre 3,6-10,8 (SDZ), 6,9-14,1 (SPZ) e 1,9-10,9 (SMX) e a precisão interdias (RSD%) foi entre 1,5-9,7, 1,7-4,1 e 2,1-10,1, respectivamente. Resultados de exatidão (tendenciosidade) foram na faixa de -8,6 a +11,9%. Portanto, o método validado é útil para a monitorização de resíduos de medicamentos avaliados em amostras de frangos, bem como todos os valores estavam dentro dos critérios aceitáveis utilizados para a segurança dos alimentos. De seis amostras analisadas, nenhuma apresentou contaminação de sulfonamidas nos níveis detectáveis estudados.

Liquid-liquid extraction combined with high performance liquid chromatography-diode array-ultra-violet for simultaneous determination of antineoplastic drugs in plasma / Extracção líquido-líquido combinado com cromatografia líquida de alta eficiência de diodo matriz-ultra-violeta para a determinação simultânea de fármacos antineoplásicos no plasma

A liquid-liquid extraction (LLE) combined with high-performance liquid chromatography-diode array detection method for simultaneous analysis of four chemically and structurally different antineoplastic drugs (cyclophosphamide, doxorubicin, 5-fluorouracil and ifosfamide) was developed. The assay was performed by isocratic elution, with a C18 column (5 µm, 250 x 4.6 mm) and mobile phase constituted by water pH 4.0- acetonitrile-methanol (68:19:13, v/v/v), which allowed satisfactory separation of the compounds of interest. LLE, with ethyl acetate, was used for sample clean-up with recoveries ranging from 60 to 98 percent. The linear ranges were from 0.5 to 100 µg mL-1, for doxorubicin and 1 to 100 µg mL-1, for the other compounds. The relative standard deviations ranged from 5.5 to 17.7 percent. This method is a fast and simple alternative that can be used, simultaneously, for the determination of the four drugs in plasma, with a range enabling quantification of the drugs in pharmacokinetics, bioequivalence and therapeutic drug-monitoring studies.

Um método de extração líquido-líquido (ELL) combinado com cromatografia líquida de alta eficiência-detector de arranjo de diodos foi desenvolvido para análise simultânea de quatro fármacos antineoplásicos quimicamente e estruturalmente diferentes (ciclofosfamida, doxorrubicina, fluoruracila e ifosfamida). O estudo foi realizado sob condições isocráticas, com coluna C18 (5µm, 250 x 4.6 mm) e fase móvel constituída por água pH 4.0-acetonitrila-metanol (68:19:13, v/v/v), que permitiu separação satisfatória dos analitos de interesse. A ELL, com acetato de etila, foi utilizada para limpeza da amostra, com recuperação variando de 60 a 98 por cento. As faixas foram lineares de 0,5 a 100 µg mL-1 para doxorrubicina e 1 a 100 µg mL-1 para os outros compostos. O desvio padrão relativo variou de 5,5 a 17,7 por cento. Este método é uma alternativa rápida e simples que pode ser usado, simultaneamente, para a determinação dos quatro fármacos em plasma, com uma faixa que permite quantificá-los em estudos de farmacocinética, bioequivalência e monitorização terapêutica.

Single gas chromatography method with nitrogen phosphorus detector for urinary cotinine determination in passive and active smokers

Nicotine is a major addictive compound in cigarettes and is rapidly and extensively metabolized to several metabolites in humans, including urinary cotinine, considered a biomarker due to its high concentration compared to other metabolites. The aim of this study was to develop a single method for determination of urinary cotinine, in active and passive smokers, by gas chromatography with a nitrogen phosphorus detector (GC-NPD). Urine (5.0 mL) was extracted with 1.0 mL of sodium hydroxide 5 mol L-1, 5.0 mL of chloroform, and lidocaine used as the internal standard. Injection volume was 1 ìL in GC-NPD. Limit of quantification was 10 ng mL-1. Linearity was evaluated in the ranges 10-1000 ng mL-1 and 500-6000 ng mL-1, with determination coefficients of 0.9986 and 0.9952, respectively. Intra- and inter-assay standard relative deviations were lower than 14.2 %, while inaccuracy (bias) was less than +11.9%. The efficiency of extraction was greater than 88.5%. Ruggedness was verified, according to Youden's test. Means of cotinine concentrations observed were 2,980 ng mL-1 for active smokers and 132 ng mL-1, for passive smokers. The results revealed that satisfactory chromatographic separation between the analyte and interferents was obtained with a ZB-1 column. This method is reliable, precise, linear and presented ruggedness in the range evaluated. The results suggest that it can be applied in routine analysis for passive and active smokers, since it is able to quantify a wide range of cotinine concentrations in urine.

A nicotina é uma substância presente no cigarro capaz de causar dependência, sendo biotransformada em vários metabólitos nos seres humanos, dentre eles a cotinina urinária, que é considerada um indicador biológico de exposição à nicotina, devido a suas altas concentrações, comparado a outras matrizes. Assim, o objetivo deste estudo foi desenvolver um único método para determinação de cotinina urinária, em amostras de urina de fumantes ativos e passivos, através de cromatografia em fase gasosa com detector de nitrogênio- fósforo (CG-DNF). Para o preparo de amostras foram utilizados 5 mL de urina, 1 mL de hidróxido de sódio 5 mol L-1, 5 mL de clorofórmio, tendo como padrão interno a lidocaína. Na faixa de concentrações de 10-1000 ng mL-1 e 500- 6000 ng mL-1, o coeficiente de determinação foi 0,9986 e 0,9952, respectivamente e, o limite de quantificação foi 10 ng mL-1. A precisão intra- e interensaio apresentou desvio padrão relativo (%) menor que 14,2% e a inexatidão foi menor que +11,9%, com uma eficiência de extração de 88,5%. O método apresentou robustez, de acordo com o teste de Youden. As concentrações médias de cotinina observadas foram 2980 ng mL-1, para fumantes ativos e 132 ng mL-1, para fumantes passivos. Os resultados sugerem que o método é confiável, preciso, linear e apresentou robustez, na faixa avaliada, podendo ser aplicado na rotina para análises de amostras de fumantes ativos e passivos, pois é capaz de quantificar uma ampla faixa de concentrações de cotinina urinária.

Determination of oxytetracycline in tomatoes by HPLC using fluorescence detection.

An analytical method for the determination of oxytetracycline (OTC) in tomatoes was developed and validated. Liquid-liquid extraction (LLE) and a solid-phase extraction (SPE) were used for sample preparation. Reversed-phase high performance liquid chromatography (RP-HPLC) using a C18 column and a mobile phase containing MeOH: calcium chloride, disodium ethylenediaminetetraacetate (EDTA) and sodium acetate, pH 7.3 (30:70, v/v), with fluorescence detection at 390nm excitation and 512nm emission, was used for separation and quantitation of OTC. The method was validated through the following performance criteria: linearity and linear range, sensitivity, selectivity, intra-day and inter-day precision, detection and quantitation limits and accuracy. Limit of quantitation show that the method developed is suitable for the determination of OTC at a level below the maximum residue limits established by the Brazilian legislations (250µgkg(-1)). Of 40 samples analyzed, none contained OTC above the limit of quantitation.

Incidência de aflatoxinas em amostras de amendoim e paçoca comercializadas na cidade de Alfenas-MG, Brasil / Incidence of aflatoxins in samples of peanuts and paçoca marketed in the city of Alfenas-MG, Brazil

Foods are subject to contamination by chemical substances, including aflatoxins, which are potentially carcinogens. The presence of these substances in food is important risk in human population and animals. The aim of this study was to determine the occurrence of aflatoxins B1, B2, G1 and G2 in samples of peanuts and paçoca ramdomly acquired in shops and food market in the city of Alfenas-MG, Brazil, from June 2006 to February 2007. The technique used for the separation, identification and quantification of the substances was a liquid-liquid extraction with subsequent thin layer chromatography (TLC). Results showed that 38 percent of peanuts samples and 13 percent of paçoca samples were contaminated with aflatoxins and the concentrations ranged from 21 to 138 μg kg-1. All positive samples exceeded the maximum level established by Brazilian Legislation (20 μg kg-1). The results obtained in this work confirm the need for frequent monitoring of the presence of aflatoxins in food.

Os alimentos estão sujeitos à contaminação por substâncias químicas, dentre elas as aflatoxinas, as quais são potencialmente carcinogênicas. A presença de tais substâncias nos alimentos constitui importante risco para a população tanto humana quanto animal. O objetivo deste estudo foi determinar a ocorrência de aflatoxinas B1, B2, G1 e G2 em amostras de amendoim e paçoca adquiridas aleatoriamente no comércio da cidade de Alfenas- MG, Brasil, no período de junho de 2006 a fevereiro de 2007. A técnica utilizada para a separação, identificação e quantificação das substâncias foi a cromatografia em camada delgada com prévia extração, líquido-líquido, dos analitos. Os resultados demonstraram que 38 por cento das amostras de amendoim e 13 por cento das amostras de paçoca estavam contaminadas com aflatoxinas, sendo que as concentrações variaram de 21 a 138 μg kg-1. Todas as amostras positivas excederam o limite máximo permitido, preconizado pela legislação brasileira de 20 μg kg-1. Os achados do presente estudo corroboram com os relatados na literatura e confirmam a necessidade do freqüente o nitoramento da presença de aflatoxinas em alimentos.

Simultaneous determination of streptomycin and oxytetracycline in agricultural antimicrobials by CZE after an experimental design.

A capillary zone electrophoresis (CZE) method was developed and validated for the simultaneous determination of both streptomycin (STP) and oxytetracycline (OTC) in bactericidal products to be used in agriculture. Using fused-silica capillaries, the influence of the electrolyte composition, pH and concentration, as well as temperature and applied voltage were investigated using a central composite design to optimize the method. The optimized electrophoretic conditions were as follows: 0.10 M sodium phosphate, pH 2.5, 7.0 kV and 20.0 degrees C. The method was validated for STP and OTC determination in agricultural formulations through the following performance criteria: linearity and linear range, sensitivity, selectivity, intra-day and inter-day precision, detectability, accuracy and ruggedness. This optimized CZE-method for the identification and quantification of STP and OTC is a potential alternative method to the HPLC methods described by the US Pharmacopeia, with the advantage that the same method could be used for the simultaneous determination of these different antibiotics.

Delta-aminolevulinic acid dehydratase activity in the general population of southern Minas Gerais, Brazil.

Blood samples were collected from 113 subjects (56 males and 57 females) living in the district of Alfenas, in southern Minas Gerais state, Brazil, to establish reference values for delta-aminolevulinic acid dehydratase activity (ALA-D, EC 4.2.1.24). The state of health of the population was confirmed by hematological and biochemical parameters analyzed in blood and urine samples. ALA-D determination was performed according to the Berlin & Schaller spectrophotometric method. Distribution may be regarded as according to normal distribution and reference values obtained, in micromol x min(-1) x L(-1) erythrocytes, were: mean (+/- SD) = 54.5 (+/- 9.8); 95% confidence interval = 52.7-56.4; lower reference value (mean-2 SD) = 34.9. Mean ALA-D activity was higher than any other published elsewhere and the reference values established are useful as a baseline for evaluating ALA-D activity when monitoring persons exposed to lead. Age, gender, drinking, or smoking did not significantly alter (Student t-test, p < or = 0.05) the reference values for ALA-D.