A rapid method for the determination of chlorine, phosphorus, and sulfur in flours of grains and legumes using wavelength dispersive x-ray flourescence spectrometry     

T Pérez Ruiz  M Hernández Córdoba  R González 《Journal of the Association of Official Analytical Chemists》1991,74(4):625-626

A rapid method for the determination of chlorine, phosphorus, and sulfur in commercial flours of wheat, barley, maize, rice, field bean, and soybean by wavelength dispersive x-ray fluorescence spectrometry has been developed. The flours are strained through a 425 microns sieve, then pelletized and measured. The total analysis time for the quantitation of chlorine, phosphorus, and sulfur is less than 20 min per sample. Calibration is carried out using a standard additions method with mixed standards. The method is accurate and precise, and appears to be adequate for routine analyses.  相似文献   

Effect of cooking temperatures on chemical changes in species of organic arsenic in seafood   总被引：2，自引：0，他引：2  

Devesa V  Martínez A  Súñer MA  Vélez D  Almela C  Montoro R 《Journal of agricultural and food chemistry》2001,49(5):2272-2276

The concentrations of arsenobetaine (AB), tetramethylarsonium ion (TMA(+)), and trimethylarsine oxide (TMAO) were determined in samples of sole, dory, hake, and sardine, raw and after being subjected to cooking processes--baking, frying, and grilling--at various temperatures. In all cases, the temperature attained inside the product during the cooking process was measured. The arsenic species extracted from the samples with methanol/water were separated by means of a column switching technique between a PRP-X100 column and a PRP-X200 column. AB was detected by hydride generation atomic absorption spectrometry, whereas TMA(+) and TMAO were detected by hydride generation atomic fluorescence spectrometry. The results obtained showed that, in all of the types of seafood studied, TMA(+) appeared after cooking, possibly because heating facilitates decarboxylation of AB to TMA(+).  相似文献   

Total and inorganic arsenic in fresh and processed fish products     

Muñoz O  Devesa V  Suñer MA  Vélez D  Montoro R  Urieta I  Macho ML  Jalón M 《Journal of agricultural and food chemistry》2000,48(9):4369-4376

Total arsenic and inorganic arsenic contents were determined in 153 samples of seafood products consumed in the Basque Country (Spain): fish (white fish and blue fish), mollusks, crustaceans, and preserved fish. White fish presented higher levels of total arsenic and lower levels of inorganic arsenic than the blue fish, indicating possible differences in the metabolization of inorganic arsenic. For total arsenic, 66% of the samples exceeded the maximum permitted level by the strictest international legislation in seafood products [1 microg g(-)(1), wet weight (ww)]. The levels of inorganic arsenic were considerably lower than the maximum authorized in New Zealand (2 microg g(-)(1), ww), the only country with legislation for inorganic arsenic in fish and fish products. It is recommended that legislation based on levels of inorganic arsenic should be established.  相似文献   

Chemical composition and antifungal activity of essential oil of Chrysactinia mexicana gray   总被引：1，自引：0，他引：1  

Cárdenas-Ortega NC  Zavala-Sánchez MA  Aguirre-Rivera JR  Pérez-González C  Pérez-Gutiérrez S 《Journal of agricultural and food chemistry》2005,53(11):4347-4349

The chemical composition of the essential oil of Chysactinia mexicana was analyzed by gas chromatography-mass spectrometry. Seventeen compounds were characterized; eucalyptol (41.3%), piperitone (37.7%), and linalyl acetate (9.1%) were found as the major components. The essential oil of leaves and piperitone completely inhibited Aspergillus flavus growth at relatively low concentrations (1.25 and 0.6 mg/mL, respectively).  相似文献   

Status and distribution of the Mediterranean monk seal Monachus monachus on the Cabo Blanco peninsula (Western Sahara-Mauritania) in 1993–1994     

Luis M. González  Alex Aguilar  Luis F. López-Jurado  Esteve Grau 《Biological conservation》1997,80(3):225-233

The current geographical distribution of the Mediterranean monk seal Monachus monachus colony inhabiting the Cabo Blanco peninsula (Western Sahara-Mauritania) is described. Its distribution range has apparently not changed since surveys conducted in 1984–1988. Sightings of adults on the Tarf el Guerguerat coast, 20 km north of the known breeding caves, suggests the existence of other possible breeding groups further north. Two caves used by the seals are described for the first time. A review of historical trends in cave occupation by seals made it possible (1) to locate the so-called ‘maternity cave’, last reported in 1949; and (2) to establish that the colony, since its discovery, has occupied at least eight caves, five of which have collapsed. An index of population size based on counts of individuals of identified morphological types indicates that, during 1993–1994, the colony was composed of c.113–165 individuals (excluding pups), a larger number than previously assumed. Counting of seals at times of maximum haul-out is proposed as a tool to monitor population trends, although it is considered unreliable for estimating absolute numbers.  相似文献   

Ultrasensitive detection of genetically modified maize DNA by capillary gel electrophoresis with laser-induced fluorescence using different fluorescent intercalating dyes     

García-Cañas V  González R  Cifuentes A 《Journal of agricultural and food chemistry》2002,50(16):4497-4502

In this work, four different fluorescent intercalating dyes are compared for the ultrasensitive CGE-LIF detection of DNA from transgenic maize in flours. The fluorescent intercalating dyes compared are YOPRO-1, SYBR-Green-I, Ethidium bromide (EthBr), and EnhanCE. For all the four dyes optimum concentrations are established, and efficient separations of DNA fragments ranging in size from 80 to 1000 bp are obtained. The comparative study demonstrates that SYBR-Green-I and YOPRO-1 provide better limits of detection (LODs) than EnhanCE or EthBr (i.e., LODs are, respectively, 700, 1000, 11300, and 97400 zmol, calculated for a 200-bp DNA fragment). Separations using YOPRO-1 are faster than those using SYBR-Green-I (30 min vs 47 min for the analysis of the 80-1000 bp DNA fragments). Also, separations using YOPRO-1 are more efficient than those using SYBR-Green-I (e.g., 2.4 x 10(6) plates/m vs 1.6 x 10(6) plates/m, respectively, calculated for the 200-bp fragment). Also, buffer depletion and cost per analysis are worse with SYBR-Green-I than with YOPRO-1. Therefore, YOPRO-1 was selected as the preferred intercalating dye. Using this fluorescent compound, analysis time reproducibility for the CGE-LIF separation of the DNA fragments is determined to be better than 1.7% (% RSD, n = 10) within the same day, and better than 1.9% (% RSD, n = 30) for three different days. Moreover, the fluorescence signal obtained using this dye is shown to vary linearly with the DNA concentration in the range studied, i.e., 1-500 ng/microL. It is demonstrated that by using this method 0.01% of transgenic maize can be detected in flour by direct injection of the PCR-amplified sample.  相似文献   

Temporal and Spatial Monitoring of the pH and Heavy Metals in a Soil Polluted by Mine Spill. Post Cleaning Effects   总被引：1，自引：0，他引：1  

Rafaela Ordóñez Fernandez  Juan Vicente Giráldez Cervera  Karl Vanderlinden  Rosa Carbonell Bojollo  Pedro González Fernández 《Water, air, and soil pollution》2007,178(1-4):229-243

The bursting of the mining dam of Aznalcollar (Seville, Spain) triggered an increase in the concentration of heavy metals in the soils of the river Guadiamar valley as a result of the leaching of the pyritic sludge deposited on them. After the cleaning operations which included, as well as mechanical clearing, the addition of different amendments, some areas with residual sludge remained, from which some heavy metals are being mobilized by the cyclical recharge and discharge processes of water in the profiles. This paper analyzes the effect of the soil recovery operations and the climatology on the concentration of metals and their distribution in the soil profile in an area affected by the toxic spill. Fourteen points have been selected in a plot in which acidity persists, there is no vegetation, and residual sludge stains can be seen at a glance. The temporal and spatial evolution of the extractable metals: Fe, Cu, Mn and Zn, the pH and the oxidable fraction has been measured in-depth. The results obtained up to now indicate a leaching of the pollutant towards deeper horizons, finding, at a depth of 757 cm, pH values of 3.5 and very high Fe and Mn concentrations available, especially in the profiles with large sized pores, with a big fraction of sand. On the surface, seasonally, there are low pH values of around 2.5 and extractable Fe contents of over 4000 ppm, which might have an influence on the quality of surface runoff or underground water.  相似文献   

Persistent effect of organic matter pulse on a sandy soil of semiarid Patagonia     

Marina González Polo  Esteban Kowaljow  Elisa Castán  Ophelie Sauzet  María Julia Mazzarino 《Biology and Fertility of Soils》2015,51(2):241-249

  相似文献   

Changes in soil nutrient content and bacterial community after 12 years of organic amendment application to a vineyard          下载免费PDF全文

M. E. Calleja‐Cervantes  A. J. Fernández‐González  I. Irigoyen  J. F. Cibriáin‐Sabalza  N. Toro  P. M. Aparicio‐Tejo  M. Fernández‐López 《European Journal of Soil Science》2015,66(4):802-812

An interesting alternative to landfills for disposing of organic residues is their addition to soil as composted organic residues. There is little information available about the long‐term benefits following prolonged periods of application. After 12 years of annual incorporation of organic amendments to the soil of a vineyard, three soil characteristics were analysed: mineral content, bacterial community and soil greenhouse gas (GHG) emissions. The organic amendments were (i) a pelletized organic compost (PEL) made from plant, animal and sewage sludge residues, (ii) a compost made from the organic fraction of municipal solid waste (OF‐MSW) and (iii) a stabilized sheep manure compost (SMC). Mineral fertilizer (NPK) and an unaltered control treatment were also included. Our results showed that long‐term application of treated residues as compost changed soil nutrient content, bacterial community and gas emission rates. For instance, SMC increased nutrients and soil organic matter (OM) throughout the experiment. There was a change in bacterial community structure, with an increase in the phylum Proteobacteria observed for all four treated soils, and an increase in the phylum Bacteroidetes for PEL, OF‐MSW and SMC treatments. Among the organically‐amended soils, the amount of Adhaeribacter increased by a factor of 2.5 times more than the control, which reported a total of 2.0% of the bacterial community compared with 5.6% for PEL, 5.2% for OF‐MSW and 5.0% for SMC. Adhaeribacter may be a genus that specializes in the degradation of residues in the different composts. The SMC treatment had the largest Chao1 estimator and was the most biodiverse of all treatments. These changes in bacterial community structure did not correlate with the observed GHG fluxes from the sampling day. The application of amendments did not affect N₂O fluxes. However, the application of treatments slightly reduced the capacity for CH₄ sequestration by soil with respect to the untreated soils. Compost is an effective method to increase soil fertility. Soil GHG emissions should be further evaluated.  相似文献   

Scanning-Electron Microscopy of the Development of the Head of Rainbow-trout (Oncorhynchus mykiss) Embryos     

M. E. González    M. J. Blánquez    C. Rojo  A. J. Puerta 《Anatomia, histologia, embryologia》1995,24(4):257-263

The development of the cephalic region of rainbow trout in the 24th, 30th and 36th stages, corresponding to the table of development by Vernier (1969), was studied using light microscopy and SEM. The 24th stage shows a voluminous cephalic region as a principal feature. At this time, most components of this region have started their differentiation. The 30th stage can be considered as an intermediary phase in the embryonic formation, and it is characterized by the high degree of differentiation between the nervous system and the sense organs. In the 36th stage, the basic final shape of the embryo has been reached. The results of this study show that the differentiation of gill lamellae and the opening of the mouth takes place later than that moment described by other authors. This suggests that development between 30th and 36th stages is a critical survival period for rainbow trout, in which respiratory and digestive functions start.  相似文献