RESUMO
BACKGROUND: Food safety has become an essential aspect of public concern and there are lots of detection means. Liquid chromatography plays a dominating role in food safety inspection because of its high separation efficiency and reproducibility. However, with the increasing complexity of real samples and monitoring requirements, conventional single-mode chromatography would require frequent column replacement and cannot separate different kinds of analytes on a single column simultaneously, which is costly and time-consuming. There is a great need for fabricating mixed-mode stationary phases and validating the feasibility of employing mixed-mode stationary phases for food safety inspection. RESULTS: This work fabricated multifunctional stationary phases for liquid chromatography to determine diverse food additives under the mixed mode of RPLC/HILIC/IEC. Two dicationic ionic liquid silanes were synthesized and bonded onto the silica gel surface. The functionalized silica was characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and elemental analysis. Both columns provide satisfactory separation performance towards 6 hydrophilic nucleosides, 4 hydrophobic polycyclic aromatic hydrocarbons, and 5 anions. Great repeatability of retention (RSD <0.1 %) and column efficiency (100330 plate/m) were obtained. Thermomechanical analysis and linear solvation energy relationship investigated the retention mechanism. Finally, the better in two prepared columns was employed to separate and determine the contents of NO2- and NO3- in vegetables(highest 4906 mg kg-1 NO3- in spinach), preservatives in bottled beverages (180.8 mg kg-1 sodium benzoate in soft drink), and melamine in milk with satisfactory performance and recovery rates ranging from 96.4 % to 105.6 %. SIGNIFICANCE: This work developed a novel scheme for preparing mixed-mode stationary phases by dicationic ionic liquid which provides great separation selectivity. Most importantly, this work proved the superiority of employing mixed-mode stationary phases for food safety inspection, which might avoid high-cost and frequent changes of columns and chromatography systems in the near future.
Assuntos
Aditivos Alimentares , Líquidos Iônicos , Dióxido de Silício , Líquidos Iônicos/química , Dióxido de Silício/química , Aditivos Alimentares/análise , Aditivos Alimentares/isolamento & purificação , Cromatografia Líquida/métodos , Nucleosídeos/isolamento & purificação , Nucleosídeos/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação , Ânions/análise , Ânions/isolamento & purificação , Ânions/química , Silanos/químicaRESUMO
This study aimed to develop a highly efficient nanocomposite composed of magnetic chitosan/molybdenum disulfide (CS/MoS2/Fe3O4) for the removal of three polycyclic aromatic hydrocarbons (PAHs)-pyrene, anthracene, and phenanthrene. Novelty was introduced through the innovative synthesis procedure and the utilization of magnetic properties for enhanced adsorption capabilities. Additionally, the greenness of chitosan as a sorbent component was emphasized, highlighting its biodegradability and low environmental impact compared to traditional sorbents. Factors influencing PAH adsorption, such as nanocomposite dosage, initial PAH concentration, pH, and contact time, were systematically investigated and optimized. The results revealed that optimal removal efficiencies were attained at an initial PAH concentration of 150 mg/L, a sorbent dose of 0.045 g, pH 6.0, and a contact time of 150 min. The pseudo-second-order kinetic model exhibited superior fitting to the experimental data, indicating an equilibrium time of approximately 150 min. Moreover, the equilibrium adsorption process followed the Freundlich isotherm model, with kf and n values exceeding 7.91 mg/g and 1.20, respectively. Remarkably, the maximum absorption capacities for phenanthrene, anthracene, and pyrene on the sorbent were determined as 217 mg/g, 204 mg/g, and 222 mg/g, respectively. These findings underscore the significant potential of the CS/MoS2/Fe3O4 nanocomposite for efficiently removing PAHs from milk and other dairy products, thereby contributing to improved food safety and public health.
Assuntos
Quitosana , Dissulfetos , Leite , Molibdênio , Nanocompostos , Hidrocarbonetos Policíclicos Aromáticos , Dissulfetos/química , Nanocompostos/química , Quitosana/química , Hidrocarbonetos Policíclicos Aromáticos/química , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação , Molibdênio/química , Leite/química , Animais , Adsorção , Cinética , Concentração de Íons de HidrogênioRESUMO
The unique properties of pillar[5]arene, including hydrophobic cavities, π-π conjugated and easy modification, make it a promising candidate as stationary phase for HPLC. Herein, we fabricated a novel propanediamine modified pillar[5]arene bonded silica as the stationary phase (PDA-BP5S) for reversed-phase liquid chromatography (RPLC). Benefiting from the significant hydrophobicity, π-π conjugative, p-π effect, and hydrogen bonding, the PDA-BP5S packed column showed high separation performance of versatile analytes involving polycyclic aromatic hydrocarbons, alkyl benzenes, phenols, arylamine, phenylethane/styrene/ phenylacetylene, toluene/m-xylene/mesitylene, halobenzenes, benzenediol and nitrophenol isomers. Especially, the separation of halobenzenes appeared to be controlled by both the size of the halogen substituents and the strength of the noncovalent bonding interactions, which was further confirmed by molecular dynamics simulation. The satisfactory separation and repeatability revealed the promising prospects of amine-pillar[5]arene-based stationary phase for RPLC.
Assuntos
Calixarenos , Cromatografia de Fase Reversa , Interações Hidrofóbicas e Hidrofílicas , Cromatografia de Fase Reversa/métodos , Calixarenos/química , Simulação de Dinâmica Molecular , Compostos de Amônio Quaternário/química , Cromatografia Líquida de Alta Pressão/métodos , Dióxido de Silício/química , Ligação de Hidrogênio , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/químicaRESUMO
Polycyclic aromatic compounds (PACs) encompass a wide variety of organic analytes that have mutagenic and carcinogenic potentials for human health and are recalcitrant in the environment. Evaluating PACs levels in fuel (e.g., gasoline and diesel), food (e.g., grilled meat, fish, powdered milk, fruits, honey, and coffee) and environmental (e.g., industrial effluents, water, wastewater and marine organisms) samples are critical to determine the risk that these chemicals pose. Deep eutectic solvents (DES) have garnered significant attention in recent years as a green alternative to traditional organic solvents employed in sample preparation. DES are biodegradable, have low toxicities, ease of synthesis, low cost, and a remarkable ability to extract PACs. However, no comprehensive assessment of the use of DESs for extracting PACs from fuel, food and environmental samples has been performed. This review focused on research involving the utilization of DESs to extract PACs in matrices such as PAHs in environmental samples, NSO-HET in fuels, and bisphenols in foods. Chromatographic methods, such as gas chromatography (GC) and high-performance liquid chromatography (HPLC), were also revised, considering the sensibility to quantify these compound types. In addition, the characteristics of DES and advantages and limitations for PACs in the context of green analytical chemistry principles (GAC) and green profile based on metrics provide perspective and directions for future development.
Assuntos
Solventes Eutéticos Profundos , Hidrocarbonetos Policíclicos Aromáticos , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação , Hidrocarbonetos Policíclicos Aromáticos/química , Solventes Eutéticos Profundos/química , Análise de Alimentos/métodos , Contaminação de Alimentos/análiseRESUMO
The epoxy propanol molecular cage bonded silica stationary phase, RCC3-GLD@silica, synthesized through the ring-opening reaction of secondary amine with epoxy propanol using RCC3-R as the scaffold unit, was successfully prepared as confirmed by infrared spectroscopy, thermogravimetric analysis, and nitrogen adsorption-desorption characterization. This stationary phase demonstrated excellent separation performance in both reversed-phase and hydrophilic chromatography modes, effectively separating a wide variety of compounds including alkylbenzenes, polycyclic aromatic hydrocarbons, phenols, anilines, sulfonamides, nucleosides, amino acids, sugars, and acids. The development of RCC3-GLD@silica benefits from the synergistic effects of its hydrophobic and hydrophilic actions, as evidenced by the U-shaped characteristic of the retention factor for nucleoside compounds with changes in the aqueous content of the mobile phase, further confirming the simultaneous presence of reversed-phase and hydrophilic chromatography mechanisms. Not only did this stationary phase successfully separate 33 compounds in reversed-phase chromatography mode, but it also separated 54 compounds in hydrophilic interaction chromatography mode, showcasing its broad separation capability from weakly polar to strongly polar compounds on a single chromatographic column. This indicates a wide application prospect in the field of chromatographic analysis.
Assuntos
Cromatografia de Fase Reversa , Interações Hidrofóbicas e Hidrofílicas , Nucleosídeos , Dióxido de Silício , Dióxido de Silício/química , Cromatografia de Fase Reversa/métodos , Nucleosídeos/isolamento & purificação , Nucleosídeos/química , Compostos de Epóxi/química , Aminoácidos/isolamento & purificação , Aminoácidos/química , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação , Hidrocarbonetos Policíclicos Aromáticos/química , Fenóis/isolamento & purificação , Fenóis/química , Cromatografia Líquida de Alta Pressão/métodosRESUMO
For the first time, a method for the simultaneous analysis of fifteen polycyclic aromatic hydrocarbons (PAHs), including light and heavy PAHs, in açaí-based food products (AFPs) was developed using vacuum-assisted sorbent extraction (VASE) combined with gas chromatography-mass spectrometry (GC-MS). The method requires no organic solvents and is amenable to full automation. To achieve optimal analytical extraction conditions, VASE parameters including stirring rate, extraction time, desorption temperature, desorption time, preheat time, and preheat temperature were optimized using sequential multivariate optimization. The method was validated and yielded limits of quantification below 1 µg kg-1 for all analytes, with recoveries ranging from 65 % to 112 % and good precision (≤11 % relative standard deviation). Additionally, the greenness and practical aspects of the method were investigated using the Green Analytical Procedure Index (GAPI), eco-scale, and the Blue Applicability Grade Index (BAGI), respectively. The VASE-GC-MS approach is suitable for routine analysis and exhibits characteristics of a green analytical method. No PAHs were detected above the limits of detection in thirty samples of AFPs.
Assuntos
Cromatografia Gasosa-Espectrometria de Massas , Limite de Detecção , Hidrocarbonetos Policíclicos Aromáticos , Cromatografia Gasosa-Espectrometria de Massas/métodos , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação , Vácuo , Extração em Fase Sólida/métodos , Contaminação de Alimentos/análise , Química Verde/métodos , Análise de Alimentos/métodos , Reprodutibilidade dos TestesRESUMO
BACKGROUND: Accurate quantitative analysis of small molecule metabolites in biological samples is of great significance. Hydroxypolycyclic aromatic hydrocarbons (OH-PAHs) are metabolic derivatives of emerging pollutants, reflecting exposure to polycyclic aromatic hydrocarbons (PAHs). Macromolecules such as proteins and enzymes in biological samples will interfere with the accurate quantification of OH-PAHs, making direct analysis impossible, requiring a series of complex treatments such as enzymatic hydrolysis. Therefore, the development of matrix-compatible fiber coatings that can exclude macromolecules is of great significance to improve the ability of solid-phase microextraction (SPME) technology to selectively quantify small molecules in complex matrices and achieve rapid and direct analysis. RESULTS: We have developed an innovative coating with a stable macromolecular barrier using electrospinning and flexible filament winding (FW) technologies. This coating, referred to as the hollow fibrous covalent organic framework@polyionic liquid (F-COF@polyILs), demonstrates outstanding conductivity and stability. It accelerates the adsorption equilibrium time (25 min) for polar OH-PAHs through electrically enhanced solid-phase microextraction (EE-SPME) technology. Compared to the powder form, F-COF@polyILs coating displays effective non-selective large-size molecular sieving. Combining gas chromatography-tandem triple quadrupole mass spectrometry (GC-MS/MS), we have established a simple, efficient quantitative analysis method for OH-PAHs with a low detection limit (0.008-0.05 ng L-1), wide linear range (0.02-1000 ng L-1), and good repeatability (1.0%-7.3 %). Experimental results show that the coated fiber exhibits good resistance to matrix interference (2.5%-16.7 %) in complex biological matrices, and has been successfully used for OH-PAHs analysis in human urine and plasma. SIGNIFICANCE: FW technology realizes the transformation of the traditional powder form of COF in SPME coating to a uniform non-powder coating, giving its ability to exclude large molecules in complex biological matrices. A method for quantitatively detecting OH-PAHs in real biological samples was also developed. Therefore, the filament winding preparation method for F-COF@polyILs coated fibers, along with fibrous COFs' morphology control, has substantial implications for efficiently extracting target compounds from complex matrices.
Assuntos
Microextração em Fase Sólida , Microextração em Fase Sólida/métodos , Estruturas Metalorgânicas/química , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação , Substâncias Macromoleculares/química , Limite de Detecção , Adsorção , Técnicas Eletroquímicas/métodosRESUMO
The improvement of the stability and adsorption properties of materials on targets in sample pre-treatment has long been an objective. Extensive efforts have been made to achieve this goal. In this work, metal-organic framework Ni-MOF precursors were first synthesized by solvothermal method using polyvinylpyrrolidone (PVP) as an ideal templating agent, stabiliser and nanoparticle dispersant. After carbonization and acid washing, the nanoporous carbon microspheres material (Ni@C-acid) was obtained. Compared with the material without acid treatment (Ni@C), the specific surface area, pore volume, adsorption performance of Ni@C-acid were increased. Thanks to its excellent characteristics (high stability, abundant benzene rings), Ni@C-acid was used as fiber coatings in headspace solid-phase microextraction (HS-SPME) technology for extraction and preconcentration of polycyclic aromatic hydrocarbons (PAHs) prior to gas chromatography-flame ionization detector (GC-FID) analysis. The experimental parameters of extraction temperature, extraction time, agitation speed, desorption temperature, desorption time and sodium chloride (NaCl) concentration were studied. Under optimal experimental conditions, the wide linear range (0.01-30 ng mL-1), the good correlation coefficient (0.9916-0.9984), the low detection limit (0.003-0.011 ng mL-1), and the high enrichment factor (5273-13793) were obtained. The established method was successfully used for the detection of trace PAHs in actual tea infusions samples and satisfied recoveries ranging from 80.94-118.62 % were achieved. The present work provides a simple method for the preparation of highly stable and adsorbable porous carbon microsphere materials with potential applications in the extraction of environmental pollutants.
Assuntos
Carbono , Limite de Detecção , Estruturas Metalorgânicas , Microesferas , Hidrocarbonetos Policíclicos Aromáticos , Microextração em Fase Sólida , Chá , Microextração em Fase Sólida/métodos , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação , Hidrocarbonetos Policíclicos Aromáticos/análise , Chá/química , Carbono/química , Estruturas Metalorgânicas/química , Porosidade , Adsorção , Níquel/química , Níquel/isolamento & purificação , Cromatografia Gasosa/métodos , Reprodutibilidade dos TestesRESUMO
In this paper, three imidazole- and C18- bifunctional silica stationary phases (Sil-Im-C18) were prepared by adjusting introduction interval of octadecyltrichlorosilane (ODS) and 3-imidazol-1-ylpropyl(trimethoxy)silane (TMPImS), which can be used for reversed-phase liquid chromatography (RPLC) and ion exchange chromatography (IEC) with adjustable performance. The successful preparation of Sil-Im-C18 were confirmed by the characterizations of elemental analysis, infrared spectroscopy (FTIR) and contact angle (CA). Chromatographic performance of Sil-Im-C18 were evaluated by the separation of Tanaka test mixture, alkylbenzenes, linear PAHs and a set of analytes with different properties (uracil, phenol, 1,2-dinitrobenzene and naphthalene), and compared with commonly used C18 column. It was found that the chromatographic performance of Sil-Im-C18 changed significantly with the difference in bonding amount of imidazole and C18. Sil-Im-C18 demonstrated the excellent separation performance towards polycyclic aromatic hydrocarbons (PAHs), phenylesters, phenylamines, phenols and inorganic anions, and notably, nucleobases and nucleosides can be separated using pure water as mobile phases. The van Deemter plot showed that the column efficiency of Sil-Im-C18-3 was 64,933 plate·m-1 for naphthalene, indicated that Sil-Im-C18 was reasonably chromatographic columns. The RSD values of retention time were 0.22 %-0.61 % for 10 needles alkylbenzenes injected continuously at 50 °C to investigate thermal stability and repeatability, all the fluctuations of k of naphthalene were less than 2.3 % for Sil-Im-C18-1 during flushing 24 h with the mobile phase at different pH values (pH = 3 and 8), the retention time of alkylbenzenes were almost same for Sil-Im-C18-1 at different time, the RSD values of retention time of alkylbenzenes were 0.45 %-2.28 % for two batches Sil-Im-C18-1, revealing the excellent repeatability, thermal stability, durability and reproducibility of Sil-Im-C18, and implying a commercial prospect.
Assuntos
Cromatografia de Fase Reversa , Imidazóis , Hidrocarbonetos Policíclicos Aromáticos , Dióxido de Silício , Imidazóis/química , Dióxido de Silício/química , Cromatografia de Fase Reversa/métodos , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação , Hidrocarbonetos Policíclicos Aromáticos/química , Silanos/química , Cromatografia por Troca Iônica/métodosRESUMO
A defumação é um processo rotineiramente empregado nos alimentos como técnica de conservação, e uma maneira de proporcionar as características sensoriais específicas. Entretanto, o processo pode levar à formação de hidrocarbonetos policíclicos aromáticos (HPAs), que são compostos com dois ou mais anéis aromáticos condensados, alguns deles considerados carcinogênicos, mutagênicos e teratogênicos. Estudos em diversos países indicam que a contaminação de produtos cárneos defumados por diferentes HPAs é elevada e frequente, e desta maneira pode apresentar risco à saúde humana. O Brasil tem sido um dos maiores consumidores de carne no mundo, com tendência de aumentar o consumo de alimentos processados, e não é conhecida a real exposição da população aos HPAs pela ingestão de produtos cárneos defumados. Não há dados nacionais recentes quanto à contaminação destes alimentos com estes produtos. Considerando este panorama, o presente trabalho tem como objetivo realizar a revisão das principais metodologias analíticas, dos aspectos regulatórios e dos níveis de HPAs detectados em produtos cárneos defumados. Ademais, são apresentadas as maneiras de reduzir a contaminação dos alimentos por estes compostos.
Smoking is a common process employed in food as a conservation technique, as well as to provide the specific sensory characteristics. However, the process can lead to the formation of polycyclic aromatic hydrocarbons (PAHs), which are composed of two or more fused aromatic rings, and some of them are considered carcinogenic, mutagenic and teratogenic. Studies conducted in several countries indicate that contamination of smoked meat products by different PAHs is high and frequent, and it may cause a risk to human health. Although Brazil has been one of the largest consumers of meat in the world, with a trend to increase the consumption of processed foods, it has not known the real population exposure to PAHs by consuming the smoked meat products. There is no recent national data on the contamination of these foods. Considering this scenario, this study aimed at reviewing the main analytical methodologies, the regulatory aspects and the levels of PAHs found in the smoked meat products. In addition, the forms to reduce the contamination by these compounds are presented.
Assuntos
Alimentos em Conserva/análise , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação , Métodos de Análise Laboratorial e de Campo , Produtos da Carne/análise , Perigo Carcinogênico , Testes de Carcinogenicidade , Testes de MutagenicidadeRESUMO
El Río Matanza-Riachuelo y sus afluentes atraviesan zonas con diferente grado de contaminación generada por las actividades agrícola-ganaderas, urbana e industrial. Los contaminantes que llegan al agua y son depositados en los sedimentos pueden ser liberados nuevamente al agua generando efectos tóxicos y/o genotóxicos sobre los organismos acuáticos. El objetivo de este trabajo fue analizar la genotoxicidad de muestras de sedimentos de la cuenca Matanza-Riachuelo obtenidas de zonas con diferentes usos del suelo. Se seleccionaron cuatro sitios de muestreo. Se utilizaron 2 métodos de extracción de contaminantes (agitación y sonicación), 2 solventes orgánicos (metanol y diclorometano) y 2 solventes inorgánicos (agua y solución ácida), obteniéndose un total de 5 extractos para cada muestra. Se realizaron mediciones de metales pesados e hidrocarburos aromáticos policíclicos (HAPs) mediante espectrofotometría de absorción atómica y CG/MS, respectivamente. La genotoxicidad se evaluó mediante el test de Ames con 2 cepas de Salmonella typhimurium (TA98 y TA100), con y sin fracción microsomal S9, y el test de Allium cepa. De los cuatro sitios estudiados, los sedimentos del Riachuelo mostraron mayores concentraciones de metales pesados y HAPs. Para el test de Ames, sólo los extractos obtenidos en diclorometano resultaron genotóxicos para la TA100 +S9 mix. Tanto los extractos inorgánicos como los orgánicos fueron citotóxicos y genotóxicos para A. cepa. Se observó una correlación negativa entre algunos compuestos HAPs y la frecuencia de micronúcleos, indicando la presencia de efectos antagónicos con otros compuestos genotóxicos. Los extractos con mayor efecto tóxico y genotóxico fueron los obtenidos con diclorometano y solución ácida. Este estudio mostró que los contaminantes orgánicos e inorgánicos extraídos de muestras de sedimento de la Cuenca Matanza-Riachuelo, con diferente grado de impacto, presentan un potencial riesgo tóxico y genotóxico para el ecosistema acuático.
The Matanza-Riachuelo River and its tributaries traverse areas with different degrees of contamination due to farming, urban and industrial activities. The pollutants entering the water are deposited in sediments, and can be released back into the water producing toxic and/or genotoxic effects on aquatic organisms. The aim of this study was to analyze the genotoxicity of sediment samples from the Matanza-Riachuelo Basin with different land uses. Four sampling sites according to the characteristics of land use were selected. Two methods of extraction (stirring and sonication), two organic solvents (methanol and dichloromethane) and two inorganic solvents (water and acid solution) were used, yielding a total of 5 extracts for each sample. Measurements of heavy metals and polycyclic aromatic hydrocarbons (PAHs) by atomic absorption spectrophotometry and GC/MS, respectively were performed. Genotoxicity was assessed using the Ames test with 2 strains of Salmonella typhimurium (TA98 and TA100) with and without S9 microsomal fraction, and the Allium cepa test. Taking into account the four sites, sediments from Riachuelo showed higher concentrations of heavy metals and PAHs. Only the dichloromethane extracts were genotoxic to the Ames test using the TA100 strain +S9 the mix. Both organic and inorganic extracts were cytotoxic and genotoxic to A. cepa. A negative correlation between some PAHs compounds and micronucleus frequency were observed, indicating the presence of antagonistic effects with other genotoxic compounds in samples. The extracts with high toxic and genotoxic effects were obtained with dichloromethane and acid solution. This study showed that organic and inorganic contaminants extracted from sediment samples from the Matanza-Riachuelo Basin, with varying degrees of impact, have potential toxic and genotoxic risk to the aquatic ecosystem.
Assuntos
Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação , Sedimentos/análise , Metais Pesados/isolamento & purificação , Genotoxicidade , Espectrofotometria Atômica/métodos , Poluição de Rios/análise , Cromatografia Gasosa/métodos , Testes de Mutagenicidade/métodosRESUMO
Polycyclic aromatic hydrocarbons (PAH) are carcinogenic compounds which contaminate water and soil, and the enzymes can be used for bioremediation of these environments. This study aimed to evaluate some environmental conditions that affect the production and activity of the catechol 1,2-dioxygenase (C12O) by Mycobacterium fortuitum in the cell free and immobilized extract in sodium alginate. The bacterium was grown in mineral medium and LB broth containing 250 mg L-1 of anthracene (PAH). The optimum conditions of pH (4.0-9.0), temperature (5-70 ºC), reaction time (10-90 min) and the effect of ions in the enzyme activity were determined. The Mycobacterium cultivated in LB shown higher growth and the C12O activity was two-fold higher to that in the mineral medium. To both extracts the highest enzyme activity was at pH 8.0, however, the immobilized extract promoted the increase in the C12O activity in a pH range between 4.0 and 8.5. The immobilized extract increased the enzymatic activity time and showed the highest C12O activity at 45 ºC, 20 ºC higher than the greatest temperature in the cell free extract. The enzyme activity in both extracts was stimulated by Fe3+, Hg2+ and Mn2+ and inhibited by NH4+ and Cu2+, but the immobilization protected the enzyme against the deleterious effects of K+ and Mg2+ in tested concentrations. The catechol 1,2-dioxygenase of Mycobacterium fortuitum in the immobilized extract has greater stability to the variations of pH, temperature and reaction time, and show higher activity in presence of ions, comparing to the cell free extract
Assuntos
Carcinógenos/análise , Carcinógenos/isolamento & purificação , Dioxigenases/análise , Ativação Enzimática , Hidrocarbonetos Policíclicos Aromáticos/análise , Hidrocarbonetos Policíclicos Aromáticos/isolamento & purificação , Mycobacterium fortuitum/crescimento & desenvolvimento , Mycobacterium fortuitum/isolamento & purificação , Microbiologia Ambiental , Enzimas/análise , MétodosRESUMO
El interés de los hidrocarburos aromáticos policíclicos (HAPs) como contaminantes alimentarios se debe a que, algunos de ellos, son conocidos cancerígenos humanos, clasificados en el grupo 2 de la Agencia Internacional de Investigación sobre el Cáncer (IARC), además de producir efectos teratógenos y otros efectos agudos (alteraciones digestivas, cefaleas, malestar general, agitación y confusión, irritación de piel y mucosas, etc.). La determinación de los niveles de estas sustancias en los alimentos, especialmente en productos de la pesca y en alimentos ahumados, se ha incrementado en los últimos años por diversas causas. Esta revisión reúne los datos más relevantes sobre las concentraciones de estos compuestos en los productos de la pesca así como los valores de ingesta alimentaria estimados para algunas poblaciones
The great interest of the polycyclic aromatic hydrocarbons (PAHs) as food contaminants is due to their well known human carcinogenic properties. Moreover, they are classified in the second group of the International Agency for Research on Cancer (IARC). These compounds also present teratogenic and acute toxic effects (digestive alterations, cephalea, malaise, cluttering, skin and mucosa irritation, etc.). The determination of the levels of these compounds in foods, especially in fishery products and smoked foods, has increased in the last years. This review gathers the most relevant data about the PAHs concentrations in fishery products at the same time that gives information about the estimated dietary intakes of PAHs for certain populations