Detection of selected trace elements in yogurt components

The objective of this study was to determine the concentrations of Cu, Cd, Pb, Mn, Cr, Co, Ni, Zn, and Hg in the white and fruit parts of commercially available yogurts (n = 30) from Nitra markets (Slovak Republic). The results were correlated to determine their relationships. Three yogurt fruit flavors were chosen and tested, strawberry (n = 10), blueberry (n = 10), and cherry (n = 10). The elements were analyzed using atomic absorption spectrophotometry. Higher concentrations of toxic elements, such as Cd and Pb, were found in the fruit parts of the yogurt, and in some cases, the tolerable limit was exceeded. The white part of the yogurt was not contaminated by toxic elements. White yogurt is a good source of nutrients for humans, but the fruit part in yogurt requires detailed monitoring and improvements in the processing techniques.     

Distribution of toxic trace elements in soil/sediment in post-Katrina New Orleans and the Louisiana Delta

This study provided a comprehensive assessment of seven toxic trace elements (As, Pb, V, Cr, Cd, Cu, and Hg) in the soil/sediment of Katrina affected greater New Orleans region 1 month after the recession of flood water. Results indicated significant contamination of As and V and non-significant contamination of Cd, Cr, Cu, Hg and Pb at most sampling sites. Compared to the reported EPA Region 6 soil background inorganic levels, except As, the concentrations of other six elements had greatly increased throughout the studied area; St. Bernard Parish and Plaquemines Parish showed greater contamination than other regions. Comparison between pre- and post-Katrina data in similar areas, and data for surface, shallow, and deep samples indicated that the trace element distribution in post-Katrina New Orleans was not obviously attributed to the flooding. This study suggests that more detailed study of As and V contamination at identified locations is needed.     

Bags with oven-dried moss for the active monitoring of airborne trace elements in urban areas

To define a harmonized methodology for the use of moss and lichen bags as active monitoring devices of airborne trace elements in urban areas, we evaluated the element accumulation in bags exposed in Naples in different spring weather conditions for 6- and 12-weeks. Three different pre-exposure treatments were applied to moss and lichen materials: water-washing, acid-washing and oven-drying. During the different exposure periods in the Naples urban environment the moss accumulated always higher amounts of elements (except Hg) than lichens and the element accumulation increased during wetter weather and higher PM₁₀ conditions. The oven pre-treatment did not substantially modify the morphology and element composition of moss and the exposure in bags of this material for 6-weeks was sufficient to detect the pattern of airborne trace elements.     

SCR脱硝尿素中微量元素的质谱法测定

建立了电感耦合等离子体质谱(ICP-MS)法测定SCR脱硝尿素中Na、Mg、Al、P、K、Ca、Cr、Fe、Ni、Cu、Zn、Pb等12种微量元素的分析方法.通过向碰撞/反应池(CRC)系统中引入氦气消除多原子离子质谱干扰,采用混合内标元素45Sc、89Y、209Bi消除基体效应.结果表明,各元素在一定范围内线性关系良好,方法的检出限为0.2~23.6 ng/L,样品的加标回收率在89.6%~108.4%之间,RSD在1.6%~3.8%之间.方法能准确测定SCR脱硝尿素中的多个微量元素,可用于SCR脱硝尿素的质量控制和安全评价.     

Development and validation of HPLC methods for analysis of chlorantraniliprole insecticide in technical and commercial formulations

Effective, selective, precise and accurate liquid chromatographic analytical methods for the analysis of a novel chlorantraniliprole insecticide in technical and formulation (coragen, 20% SC) have been optimized and validated. Eight methods were designed based on different mobile phases, temperature and two HPLC columns. The mobile phase consists of two mixtures (acetonitrile:water, 70:30 and methanol:water, 70:30) with 25 or 40ºC. HPLC analysis of chlorantraniliprole was carried out at a wavelength of 260 nm, with a flow rate of 0.8 mL/min. The calibration curves showed a good linear relationship (R² ? 0.99) in the injected quantities ranged from 0.0125 to 1.00 μg. Limit of detection (LOD) was found to be 3.94 to 14.56 ng and from 5.95 to 12.93 ng using the analytical methods I to IV by MicroPack CN-10 and V-VIII by ZORBAX Eclips Plus C18 columns, respectively, based on SDslope values. ZORBAX Eclips Plus C18 column with method VI was the best one (R² = 1.00 and RSD = 0.30), short retention time (4.936 min), high theoretical plates per column (65457.15) compared to others and LOD = 6.49 ng. The accuracy of the best method was demonstrated by recovery rates of 83.04% to 98.50% for grape samples supplemented with 5, 10 and 50 mg chlorantraniliprole/kg.     

Distribution and seasonal variability of trace elements in atmospheric particulate in the Venice Lagoon

Size distribution and selected element concentrations of atmospheric particulate matter (PM) were investigated in the Venice Lagoon, at three sites characterised by different anthropogenic influence. The PM₁₀ samples were collected in six size fractions (10-7.2, 7.2-3.0, 3.0-1.5, 1.5-0.95; 0.95-0.49 and <0.49 μm) with high volume cascade impactors, and the concentration of 17 elements (Al, As, Ca, Cd, Co, Cu, Fe, K, Li, Mg, Mn, Na, Ni, Pb, Sr, V, Zn) was determined by inductively coupled plasma quadrupole mass spectroscopy. More than 1 year of sampling activities allowed the examination of seasonal variability in size distribution of atmospheric particulates and element contents for each site.At all the stations, particles with an aerodynamic diameter <3 μm were predominant, thus accounting for more than 78% of the total aerosol mass concentration. The highest PM₁₀ concentrations for almost all elements were found at the site which is more influenced by industrial and urban emissions. Similarity in size distribution of elements at all sites allowed the identification of three main behavioural types: (a) elements found mainly within coarse particles (Ca, Mg, Na, Sr); (b) elements found mainly within fine particles (As, Cd, Ni, Pb, V) and (c) elements with several modes spread throughout the entire size range (Co, Cu, Fe, K, Zn, Mn).Factor Analysis was performed on aerosol data separately identified as fine and coarse types in order to examine the relationships between the inorganic elements and to identify their origin. Multivariate statistical analysis and assessment of similarity in the size distribution led to similar conclusions on the sources.     

Concentration of trace elements in feathers of three Antarctic penguins: Geographical and interspecific differences

Antarctica is often considered as one of the last pristine regions, but it could be affected by pollution at global and local scale. Concentrations of Al, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Cd and Pb were determinated by ICP-MS in feathers (n = 207 individuals) of gentoo, chinstrap and Adélie penguin collected in 8 locations throughout the Antarctic Peninsula (2006-2007). The highest levels of several elements were found in samples from King George Island (8.08, 20.29 and 1.76 μg g⁻¹ dw for Cr, Cu and Pb, respectively) and Deception Island (203.13, 3.26 and 164.26 μg g⁻¹ dw for Al, Mn and Fe, respectively), where probably human activities and large-scale transport of pollutants contribute to increase metal levels. Concentrations of Cr, Mn, Cu, Se or Pb, which are similar to others found in different regions of the world, show that some areas in Antarctica are not utterly pristine.     

Specific accumulation of cadmium and other trace elements in Sarcodon imbricatus using ICP-MS with a chemometric approach

Fungi can effectively accumulate various metallic elements, metalloids and non-metals in fruiting bodies. This study provides information on the accumulation of Ag, As, Ba, Cd, Co, Cs, Cu, Cr, Li, Mn, Ni, Pb, Rb, Sr, V, Tl, U and Zn in the edible mushroom Sarcodon imbricatus (L.) P. Karst. using the technique of inductively coupled plasma – mass spectrometry with a dynamic reaction cell mode. Mushrooms were foraged from four regions in Poland. Baseline concentrations of minerals, expressed in mg kg^?1 dry biomass (db), were in the composite samples of caps in the range: for Ag (0.27–0.29), As (1.0–1.9), Ba (0.31–0.45), Cd (4.5–6.3), Co (0.23–1.9), Cu (28–35), Cr (0.19–0.29), Cs (20–38), Li (0.013–0.020), Mn (5.9–8.8), Ni (0.81–1.4), Pb (0.94–1.6), Rb (490–700), Sr (0.14–0.19), Tl (0.058–0.11), U (0.002–0.002), V (0.044–0.054) and Zn (140–160). Concentration levels of Ag, As, Cd, Cs, Pb and Zn were higher in caps than in stipes of S. imbricatus, whereas for other elements the distribution between caps and stipes was nearly equal or for some differed depending on the location. Certainly, the content of toxic Cd in S. imbricatus was elevated (0.45–0.63 mg kg^?1 in fresh caps) and therefore eating this mushroom could increase exposure to Cd. In addition, the content of toxic As in S. imbricatus was elevated.     

Contamination by arsenic and other trace elements of tube-well water along the Mekong River in Lao PDR

Arsenic and other trace element concentrations were determined for tube-well water collected in the Lao PDR provinces of Attapeu, Bolikhamxai, Champasak, Savannakhet, Saravane, and Vientiane. Water samples, especially from floodplain areas of central and southern Laos, were significantly contaminated not only with As, but with B, Ba, Mn, U, and Fe as well. Total As concentrations ranged from <0.5 μg L⁻¹ to 278 μg L⁻¹, with over half exceeding the WHO guideline of 10 μg L⁻¹. 46% of samples, notably, were dominated by As(III). Samples from Vientiane, further north, were all acceptable except on pH, which was below drinking water limits. A principal component analysis found associations between general water characteristics, As, and other trace elements. Causes of elevated As concentrations in Lao tube wells were considered similar to those in other Mekong River countries, particularly Cambodia and Vietnam, where young alluvial aquifers give rise to reducing conditions.     

Interactions between accumulation of trace elements and macronutrients in Salix caprea after inoculation with rhizosphere microorganisms

Although the beneficial effects on growth and trace element accumulation in Salix spp. inoculated with microbes are well known, little information is available on the interactions among trace elements and macronutrients. The main purpose of this study was to assess the effect of phytoaugmentation with the rhizobacteria Agromyces sp., Streptomyces sp., and the combination of each of them with the fungus Cadophora finlandica on biomass production and the accumulation of selected trace elements (Zn, Cd, Fe) and macronutrients (Ca, K, P and Mg) in Salix caprea grown on a moderately polluted soil. Dry matter production was significantly enhanced only upon inoculation with Agromyces sp. Regarding the phytoextraction of Cd and Zn, shoot concentrations were mostly increased after inoculation with Streptomyces sp. and Agromyces sp. + C. finlandica. These two treatments also showed higher translocation factors from roots to the leaves for both Cd and Zn. The accumulation of Cd and Zn in shoots was related to increased concentrations of K. This suggests that microorganisms that contribute to enhanced phytoextraction of Cd and Zn affect also the solubility and thus phytoavailability of K. This study suggests that the phytoextraction of Zn and Cd can be improved by inoculation with selected microbial strains.     

Leaf accumulation of trace elements and polycyclic aromatic hydrocarbons (PAHs) in Quercus ilex L

Quercus ilex L. leaves were collected four times in one year at six urban sites and one remote area in order to determine trace element and PAH accumulation through concomitant analyses of unwashed and water-washed leaves. Both unwashed and washed leaves showed the highest amounts of trace elements and PAHs in the urban area. Unwashed leaves showed greater differences between urban and remote areas and among the urban sites than washed leaves for trace element and PAH concentrations. Water-washing resulted in a significant (P<0.001) decrease in leaf concentrations of Cr, Cu, Fe, Pb, V and Zn. By contrast, Cd and total PAH concentrations showed no differences between unwashed and washed leaves.     

Validation and application of an analytical method for determining pesticides in the gas phase of ambient air

A method for determining atmospheric concentrations of eight pesticides applied to corn and soybean crops in Mato Grosso state, Brazil is presented. The method involved a XAD-2 resin cartridge coupled to a low volume air pump at 2 L min^?1 over 8 hours. Pesticides were recovered from the resin using sonication with n-hexane:ethyl acetate and determined by GC-MS. Good accuracy (76–128%) and precision (CV < 20%) were obtained for atrazine, chlorpyrifos, alpha- and beta-endosulfan, endosulfan sulfate, flutriafol, malathion, metolachlor and permethrin. Method detection ranged from 9.0 to 17.9 ng m^?3. This method was applied to 61 gas phase samples collected between December 2008 and June 2009. Atrazine and endosulfan were detected both in urban and rural areas indicating the importance of atmospheric dispersion of pesticides in tropical areas. The simple and efficient extraction method and sampling system employed was considered suitable for identifying pesticides in areas of intense agricultural production.     

Validation and global uncertainty of a gas chromatographic with mass spectrometry method for fenamidone analysis in grapes and wines

Fenamidone is an imidazolinone fungicide recently introduced in viticulture practices. This work reports the validation and assessment of global uncertainty of a gas chromatographic with mass spectrometry method to analyze fenamidone in grapes and wines. This method consists in a simple and fast liquid-liquid extraction step followed by chromatographic determination. Limits of detection for fenamidone in grapes and wines were, respectively, 0.05 mg/kg and 0.06 mg/L, precision was below 9.4% and average recovery was 89 ± 5%. In the concentration range from 0.05 to 1.00 mg/kg (or mg/L) of fenamidone, global uncertainty calculated following the EURACHEM/CITAC rules, and also by the Horwitz function, was below 25%. The EURACHEM/CITAC global uncertainty budget used gave lower estimates than those obtained from the Horwitz function.     

Direct and indirect methods for chromium identification in industrial wastes

The examinations of selected wastes and stream sediments from the vicinity of a chemical plant by sequential extraction procedures and direct methods, SEM/EDX and XRD, were carried out in order to identify the different forms of chromium, particularly as they are released to potential mobility. The results show that the top and bottom waste samples contain 37,756 and 53,650 μg g¹ Cr, respectively, but about 7% and 2% of the total chromium type Cr(VI). The chemical extraction results show that the mobility of Cr in the upper part of the waste pile is significantly higher than in the bottom section; the exchangeable form of Cr accounts for 25% and < 1%, respectively, the last one irrespective of redox conditions. About 50% of Cr is associated with the reducible fraction of the top waste, and similar with the residual fraction in the bottom waste. Oxidation of the bottom waste shift some portion of Cr from residual to the moderately reducible fraction. The major Cr-forms in the river sediments are compounded with Fe-oxides. The < 2 μm size fraction of the selected sediment sample, particular enriched in chromium contained up to 73,000 μg g¹ Cr with about 95% of this in the moderately reducible fraction, predominantly bound with oxyhydroxides. SEM/EDX and XRD analysis of wastes and river sediment indicate that the main insoluble Cr-phase is ferroan — (Mg, Fe) (Cr, Al)²O⁴ which would be dissolved mainly in the residual fraction.     

Extraction and clean-up methods for organochlorine pesticides determination in milk

Organochlorine pesticides (OCPs) can cause environmental damage and human health risks since they are lipophilic compounds with high resistance to degradation and long half-lives in humans. As most persistent OCPs have been banned years ago, it is expected to find these compounds at trace levels in environment. Therefore, increasingly sensitive and reliable analytical techniques are required to ensure effective monitoring of these compounds. The aim of this review is to discuss extraction and clean-up methods used to monitor OCP residues in milk, reported in the last 20 years. To carry out this review, an exhaustive bibliographic review was conducted. Despite the disadvantages of conventional extraction and clean-up methods, such as liquid–liquid, solid-phase or Soxhlet extractions, these procedures are still used due to their reliability. New extraction methods, like solid-phase microextraction, matrix solid-phase dispersion or QuEChERS, have not been thoroughly evaluated for OCP determination in milk. Almost all the methodologies analyzed in this review presented good performance characteristics according to the performance acceptability criteria set in SANCO’s procedure. Comparison between limits of quantification (LOQ) and detection (LOD), for the reported methodologies, is not always possible due to the heterogeneity of the units. Thus, researchers should take into account an homogenization of LOD and LOQ units, according to the international regulations and MRLs established. Finally, more research is necessary to obtain the ideal methodology for OCPs determination in milk, which comprises the environmentally friendly characteristics of the new techniques and the reliability of the traditional methodologies.     

Analytical methods for the determination of alachlor,metolachlor, simazine and atrazine mobility in soils

Abstract

A method for the determination of the mobility of the herbicides, alachlor, metolachlor, simazine and atrazine in soil is described . The method is based on the use of soil thin‐layer chromatography (TLC) and does not require the use of radiolabelled compounds. Soil on the TLC plate after development was separated into various bands, the material in each band was extracted with solvents and analyzed by gas chromatography.     

Method validation for control determination of mercury in fresh fish and shrimp samples by solid sampling thermal decomposition/amalgamation atomic absorption spectrometry

A method for the determination of total mercury in fresh fish and shrimp samples by solid sampling thermal decomposition/amalgamation atomic absorption spectrometry (TDA AAS) has been validated following international foodstuff protocols in order to fulfill the Brazilian National Residue Control Plan. The experimental parameters have been previously studied and optimized according to specific legislation on validation and inorganic contaminants in foodstuff. Linearity, sensitivity, specificity, detection and quantification limits, precision (repeatability and within-laboratory reproducibility), robustness as well as accuracy of the method have been evaluated. Linearity of response was satisfactory for the two range concentrations available on the TDA AAS equipment, between approximately 25.0 and 200.0 μg kg^?1 (square regression) and 250.0 and 2000.0 μg kg^?1 (linear regression) of mercury. The residues for both ranges were homoscedastic and independent, with normal distribution. Correlation coefficients obtained for these ranges were higher than 0.995. Limits of quantification (LOQ) and of detection of the method (LDM), based on signal standard deviation (SD) for a low-in-mercury sample, were 3.0 and 1.0 μg kg^?1, respectively. Repeatability of the method was better than 4%. Within-laboratory reproducibility achieved a relative SD better than 6%. Robustness of the current method was evaluated and pointed sample mass as a significant factor. Accuracy (assessed as the analyte recovery) was calculated on basis of the repeatability, and ranged from 89% to 99%. The obtained results showed the suitability of the present method for direct mercury measurement in fresh fish and shrimp samples and the importance of monitoring the analysis conditions for food control purposes. Additionally, the competence of this method was recognized by accreditation under the standard ISO/IEC 17025.     

Evaluation and validation of two different chromatographic methods (HPLC and LC-MS/MS) for the determination and confirmation of ochratoxin A in pig tissues

This study was undertaken to compare two different analytical methods for the determination and confirmation of ochratoxin A (OTA) in blood serum, kidney and liver of pigs. Sample clean-up was based on liquid-liquid phase extraction. The detection of OTA was accomplished with high-performance liquid chromatography (HPLC) combined either with fluorescence detection (FL) or electro spray ionization (ESI+) tandem mass spectrometry (MS–MS). Comparative method evaluation was based on the investigation of 90 samples of blood serum, kidney and liver per animal originating from different regions of Serbia. The analytical results are discussed in view of the respective method validation data and the corresponding experimental protocols. In general, analytical data obtained with (LC–MS–MS) liquid chromatography electro spray tandem mass spectro metry detection offered comparable good results at the sub-ppb concentration level. The results indicate that the liquid chromatography electro spray tandem mass spectrometric (LC-MS/MS) method was more specific and sensitive for the analysis and confirmation of ochratoxin A in pig tissues then high pressure liquid chromatography (HPLC) method after methylation of OTA.