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Use of ground crawfish shells for the removal of chromium in solution
23 October 2012,
09:32:38
Publication year:
2012
Source:Microchemical Journal, Volume 105
Anita Morris, Srujana Beeram, Carey J. Hardaway, Joel C. Richert, Joseph Sneddon
Crawfish shells are an abundant waste product that has the potential to remediate contaminated bodies of water. This study demonstrates that ground crawfish shell could be used as an effective biosorbent material for the treatment of chromium in contaminated aqueous solutions. Phase I experiments determined that the adsorption was completed within 2h. For the time periods examined it could be concluded that the maximum chromium adsorption occurs within the first 2h. Phase II experiments demonstrated that chromium adsorption increased with sample volume and concentration, however the efficiency decreased with increasing sample volume for the relative high concentrations of chromium. Phase III experiments showed that chitin is a major constituent for biosorption of chromium and likely other metals in crustacean species including crawfish. Salinity experiments showed that salt (sodium chloride) at the 30ppt (parts per thousand) concentrations does not affect the crawfish shell ability to adsorb chromium. The pH was the most important factor for chromium adsorption by the crawfish powder. Chromium adsorption increased with increasing pH. The presence of lead ions did not significantly interfere with the adsorption of chromium ions onto the crawfish shell powder for the relatively high concentrations examined. However, for relatively low concentrations the chromium adsorption was somewhat suppressed by the lead ions.
Source:Microchemical Journal, Volume 105
Anita Morris, Srujana Beeram, Carey J. Hardaway, Joel C. Richert, Joseph Sneddon
Crawfish shells are an abundant waste product that has the potential to remediate contaminated bodies of water. This study demonstrates that ground crawfish shell could be used as an effective biosorbent material for the treatment of chromium in contaminated aqueous solutions. Phase I experiments determined that the adsorption was completed within 2h. For the time periods examined it could be concluded that the maximum chromium adsorption occurs within the first 2h. Phase II experiments demonstrated that chromium adsorption increased with sample volume and concentration, however the efficiency decreased with increasing sample volume for the relative high concentrations of chromium. Phase III experiments showed that chitin is a major constituent for biosorption of chromium and likely other metals in crustacean species including crawfish. Salinity experiments showed that salt (sodium chloride) at the 30ppt (parts per thousand) concentrations does not affect the crawfish shell ability to adsorb chromium. The pH was the most important factor for chromium adsorption by the crawfish powder. Chromium adsorption increased with increasing pH. The presence of lead ions did not significantly interfere with the adsorption of chromium ions onto the crawfish shell powder for the relatively high concentrations examined. However, for relatively low concentrations the chromium adsorption was somewhat suppressed by the lead ions.
Highlights
► Use of crawfish shells for biosorption ► Uptake of chromium in solution in less than 2h ► pH affected uptake. ► Salt at ppt and lead ions had no effect on uptake.Method development for the determination of alkali metals in samples from pyrochemical reprocessing using ICP-OES and comparison with sector field ICP-MS
23 October 2012,
09:32:38
Publication year:
2012
Source:Microchemical Journal, Volume 105
Michael Krachler, Stefaan Van Winckel, Mariangela Cardinale, Brian Lynch, Tsuyoshi Murakami
An analytical procedure for the reliable determination of the alkaline elements Na, K, and Li in radioactive samples was developed and validated. To this end, a high efficiency, desolvating nebulizer (Apex E) was coupled to a commercial high resolution ICP-OES instrument operated at 1000W. Because of their radioactive nature, all investigated samples were handled in appropriate glove boxes operated in under-pressure, following strict safety and security procedures. After optimization of the ICP-OES operational parameters, detection limits (LODs) of 0.15μg/L, 0.8μg/L, and 1.3μg/L were obtained for Li (λ=670.784nm), Na (λ=589.592nm), and K (λ=766.490nm). Compared to conventional sample uptake rates of 1–2mL/min, the 350μL/min used in this study helped to lower the radiation dose to the ICP-OES operator and produced much less radioactive waste while at the same time improving LODs. Calibration curves were linear up to 4mg/L with a correlation coefficient of better than 0.999. Because of its robust and reproducible performance, no internal standard was required to correct for potential drifts in sensitivity of the ICP-OES. Three certified water reference materials (BCR®-617, LGC6177, SRM® 1643a) were employed to assess the accuracy of the developed ICP-OES procedure, the results of which underpin its reliability. In addition, Na and K concentrations calculated from emission intensities measured at two wavelengths confirmed that each dataset is consistent in itself. A comparison of sector field ICP-MS results of 23 samples originating from pyrochemical reprocessing with the data obtained applying the newly developed ICP-OES procedure revealed that the latter provides a reliable, straightforward and more robust analytical approach to determine Na, K, and Li in radioactive specimens.
Source:Microchemical Journal, Volume 105
Michael Krachler, Stefaan Van Winckel, Mariangela Cardinale, Brian Lynch, Tsuyoshi Murakami
An analytical procedure for the reliable determination of the alkaline elements Na, K, and Li in radioactive samples was developed and validated. To this end, a high efficiency, desolvating nebulizer (Apex E) was coupled to a commercial high resolution ICP-OES instrument operated at 1000W. Because of their radioactive nature, all investigated samples were handled in appropriate glove boxes operated in under-pressure, following strict safety and security procedures. After optimization of the ICP-OES operational parameters, detection limits (LODs) of 0.15μg/L, 0.8μg/L, and 1.3μg/L were obtained for Li (λ=670.784nm), Na (λ=589.592nm), and K (λ=766.490nm). Compared to conventional sample uptake rates of 1–2mL/min, the 350μL/min used in this study helped to lower the radiation dose to the ICP-OES operator and produced much less radioactive waste while at the same time improving LODs. Calibration curves were linear up to 4mg/L with a correlation coefficient of better than 0.999. Because of its robust and reproducible performance, no internal standard was required to correct for potential drifts in sensitivity of the ICP-OES. Three certified water reference materials (BCR®-617, LGC6177, SRM® 1643a) were employed to assess the accuracy of the developed ICP-OES procedure, the results of which underpin its reliability. In addition, Na and K concentrations calculated from emission intensities measured at two wavelengths confirmed that each dataset is consistent in itself. A comparison of sector field ICP-MS results of 23 samples originating from pyrochemical reprocessing with the data obtained applying the newly developed ICP-OES procedure revealed that the latter provides a reliable, straightforward and more robust analytical approach to determine Na, K, and Li in radioactive specimens.
Overview of hyphenated techniques using an ICP-MS detector with an emphasis on extraction techniques for measurement of metalloids by HPLC–ICPMS
23 October 2012,
09:32:38
Publication year:
2012
Source:Microchemical Journal, Volume 105
William Maher, Frank Krikowa, Michael Ellwood, Simon Foster, Rajani Jagtap, George Raber
In this review we present an overview of hyphenated techniques using an ICPMS detector with an emphasis on extraction techniques for the measurement of metalloids by high pressure liquid chromatography–inductively plasma mass spectrometry (HPLC–ICPMS). Five modes of using hyphenated ICPMS systems; HPLC–ICPMS, HPLC–hydride generation-ICPMS, Cryogenic trapping ICPMS, in-situ Cryogenic trapping ICPMS and Gas Chromatography–ICPMS are described together with their application for the measurement of arsenic, selenium, mercury and antimony species. Two classes of metalloid species are described; “Easy to extract species,” stable species existing as discrete molecules or relatively weakly bound to cellular constituents, and Hard to extract species,” unstable species that dissociate on extraction and species incorporated within cellular constituents such as proteins. Measurements described include, arsenic species: arsenobetaine, arsenoribosides, arsenic bound to lipids and phytochelatins and other minor arsenic species including thioarsenic species. Selenium species: selenocysteine and selenomethionine, Se-methyl selenomethionine, Se-methyl selenocysteine, y-glutamyl-Se-methylselenocysteine, dimethylselenide and dimethyldiselenide. Mercury species: inorganic Hg and methyl Hg. Antimony species: antimonite and antimonate. Germanium species: inorganic. Extraction methods are discussed in terms of their extraction efficiencies, stability of species and artifact formation.
Source:Microchemical Journal, Volume 105
William Maher, Frank Krikowa, Michael Ellwood, Simon Foster, Rajani Jagtap, George Raber
In this review we present an overview of hyphenated techniques using an ICPMS detector with an emphasis on extraction techniques for the measurement of metalloids by high pressure liquid chromatography–inductively plasma mass spectrometry (HPLC–ICPMS). Five modes of using hyphenated ICPMS systems; HPLC–ICPMS, HPLC–hydride generation-ICPMS, Cryogenic trapping ICPMS, in-situ Cryogenic trapping ICPMS and Gas Chromatography–ICPMS are described together with their application for the measurement of arsenic, selenium, mercury and antimony species. Two classes of metalloid species are described; “Easy to extract species,” stable species existing as discrete molecules or relatively weakly bound to cellular constituents, and Hard to extract species,” unstable species that dissociate on extraction and species incorporated within cellular constituents such as proteins. Measurements described include, arsenic species: arsenobetaine, arsenoribosides, arsenic bound to lipids and phytochelatins and other minor arsenic species including thioarsenic species. Selenium species: selenocysteine and selenomethionine, Se-methyl selenomethionine, Se-methyl selenocysteine, y-glutamyl-Se-methylselenocysteine, dimethylselenide and dimethyldiselenide. Mercury species: inorganic Hg and methyl Hg. Antimony species: antimonite and antimonate. Germanium species: inorganic. Extraction methods are discussed in terms of their extraction efficiencies, stability of species and artifact formation.
Highlights
► Five modes of using hyphenated ICPMS systems are described. ► Extraction of species is reviewed in terms of their extraction efficiencies, stability of species and artifact formation. ► Easy to extract species are identified as species existing as discrete molecules or weakly bound to cellular constituents. ► Hard to extract species are identified as species that dissociate or incorporated within cellular constituents e.g. proteins.Mass spectrometry-based multiplexing for the analysis of biomarkers in drug development and clinical diagnostics — How much is too much?
23 October 2012,
09:32:38
Publication year:
2012
Source:Microchemical Journal, Volume 105
Uwe Christians, Jacek Klepacki, Touraj Shokati, Jost Klawitter, Jelena Klawitter
Biomarkers, or more specifically molecular markers, can detect biochemical changes associated with disease processes and drug effects before histopathological and pathophysiological changes occur. Multiplexing technologies such as high-performance liquid chromatography/ mass spectrometry (LC-MS) allow for the measurement of molecular marker patterns that confer significantly more information than the measurement of a single parameter alone. The use of multiplexing assays for drug development, and as diagnostic tools, is attractive but will require regulatory review and approval and thus requires validation following regulatory guidance. Multiplexing assays always constitute a compromise. The number of analytes that can reasonably be included in a mass spectrometry-based multiplexing assay depend on the physico-chemical properties of the analytes and their integration into a single assay in terms of extraction, HPLC separation, ionization conditions and mass spectrometry detection. Another aspect includes biomedical considerations such as the differences in physiological concentrations of analytes, the required concentration range, and how much variability is acceptable before the clinical utility of a marker is negatively affected. Regulatory considerations include validation and quality control during sample analysis. Current bioanalytical regulatory guidelines have mostly been developed for single drug compounds and are not always adequate for multiplexing molecular marker assays that often quantify endogenous compounds. Specific guidances for multiplexing assays should be developed. Even if it is possible to integrate a wide variety and large number of analytes into a multiplexing assay, it should always be taken into consideration that a set of shorter, more specialized assays, may offer a more manageable and efficient alternative.
Source:Microchemical Journal, Volume 105
Uwe Christians, Jacek Klepacki, Touraj Shokati, Jost Klawitter, Jelena Klawitter
Biomarkers, or more specifically molecular markers, can detect biochemical changes associated with disease processes and drug effects before histopathological and pathophysiological changes occur. Multiplexing technologies such as high-performance liquid chromatography/ mass spectrometry (LC-MS) allow for the measurement of molecular marker patterns that confer significantly more information than the measurement of a single parameter alone. The use of multiplexing assays for drug development, and as diagnostic tools, is attractive but will require regulatory review and approval and thus requires validation following regulatory guidance. Multiplexing assays always constitute a compromise. The number of analytes that can reasonably be included in a mass spectrometry-based multiplexing assay depend on the physico-chemical properties of the analytes and their integration into a single assay in terms of extraction, HPLC separation, ionization conditions and mass spectrometry detection. Another aspect includes biomedical considerations such as the differences in physiological concentrations of analytes, the required concentration range, and how much variability is acceptable before the clinical utility of a marker is negatively affected. Regulatory considerations include validation and quality control during sample analysis. Current bioanalytical regulatory guidelines have mostly been developed for single drug compounds and are not always adequate for multiplexing molecular marker assays that often quantify endogenous compounds. Specific guidances for multiplexing assays should be developed. Even if it is possible to integrate a wide variety and large number of analytes into a multiplexing assay, it should always be taken into consideration that a set of shorter, more specialized assays, may offer a more manageable and efficient alternative.
A review on approaches to bio distribution studies about gold and silver engineered nanoparticles by inductively coupled plasma mass spectrometry
23 October 2012,
09:32:38
Publication year:
2012
Source:Microchemical Journal, Volume 105
Petra Krystek
This paper gives a general overview about bio distribution studies which are especially related to engineered nanoparticles (NPs) made of gold and silver. The analysis of biological materials from bio distribution studies plays a significant role in the application of atomic spectrometry to study NPs. Therefore, special focus is given to the generally applied strategy as well as the use of the inductively coupled plasma mass spectrometry (ICP-MS) technique for the determination of the NPs containing metals. An overview of the recent research applications on gold and silver NPs is also presented. While for gold NPs a large variety of very different sizes, shape and coating are known, they also provide many opportunities in imaging, diagnostics, and therapies of nanomedicine. Hence, their bio kinetics in the body are prerequisites for specific tailoring of nanomedicinal applications and for a comprehensive risk assessment. Silver NPs are applied in a lot of consumer products; therefore it is useful to get a better understanding of their in vivo distribution.
Source:Microchemical Journal, Volume 105
Petra Krystek
This paper gives a general overview about bio distribution studies which are especially related to engineered nanoparticles (NPs) made of gold and silver. The analysis of biological materials from bio distribution studies plays a significant role in the application of atomic spectrometry to study NPs. Therefore, special focus is given to the generally applied strategy as well as the use of the inductively coupled plasma mass spectrometry (ICP-MS) technique for the determination of the NPs containing metals. An overview of the recent research applications on gold and silver NPs is also presented. While for gold NPs a large variety of very different sizes, shape and coating are known, they also provide many opportunities in imaging, diagnostics, and therapies of nanomedicine. Hence, their bio kinetics in the body are prerequisites for specific tailoring of nanomedicinal applications and for a comprehensive risk assessment. Silver NPs are applied in a lot of consumer products; therefore it is useful to get a better understanding of their in vivo distribution.
Identification of volatile iron species generated by UV photolysis
23 October 2012,
09:32:38
Publication year:
2012
Source:Microchemical Journal, Volume 105
Patricia Grinberg, Ralph E. Sturgeon, Graeme Gardner
The volatile products of photochemical generation (PVG) of iron from solutions of formic and acetic acids were examined by GC-MS. Iron pentacarbonyl was the sole analytical species detected in both cases, as confirmed by comparison of the results with a NIST reference spectrum. Silylation of the interior surfaces of the quartz tubing comprising the photochemical reactor essentially eliminated memory effects such that signal duration was determined simply by the residence time of the sample solution.
Source:Microchemical Journal, Volume 105
Patricia Grinberg, Ralph E. Sturgeon, Graeme Gardner
The volatile products of photochemical generation (PVG) of iron from solutions of formic and acetic acids were examined by GC-MS. Iron pentacarbonyl was the sole analytical species detected in both cases, as confirmed by comparison of the results with a NIST reference spectrum. Silylation of the interior surfaces of the quartz tubing comprising the photochemical reactor essentially eliminated memory effects such that signal duration was determined simply by the residence time of the sample solution.
Highlights
► The volatile products of PVG of Fe were examined by GC-MS. ► Iron pentacarbonyl was the specie detected in the presence of formic and acetic acid. ► Comparison of the results with a NIST reference spectrum. ► Silylation of the interior surfaces of the quartz tubing eliminated memory effects.Roles of electrode material and geometry in liquid sampling-atmospheric pressure glow discharge (LS-APGD) microplasma emission spectroscopy
23 October 2012,
09:32:38
Publication year:
2012
Source:Microchemical Journal, Volume 105
C. Derrick Quarles, Benjamin T. Manard, Carolyn Q. Burdette, R. Kenneth Marcus
The roles of the electrode material and geometry on the performance of the liquid sampling-atmospheric pressure glow discharge (LS-APGD) optical emission spectroscopy source are described. The LS-APGD source has been interfaced to a high resolution JY RF-5000 polychromator allowing for simultaneous multiple element detection. This LS-APGD source operates at currents of 20–60mA and solution flow rates of 0.1–0.4mLmin−1. A glow discharge is generated between the surface of the electrolyte test solution exiting a glass capillary and the end of a metallic counterelectrode. Described here is an evaluation of how the counterelectrode material identity (copper, nickel, and stainless steel) and the electrode configuration (geometry) influence the analyte emission responses for a test solution containing Ag, Cr, Cu, Mg, Ni, and Zn in 1M HNO3. Studies of the effect of liquid flow rates reveal that 0.3mLmin−1 provides optimal analyte emission responses as it relates to peak intensity, peak area, and peak widths. Use of nickel as the counterelectrode material provided the best reproducibility for analyte emission responses with 8.9–13.0%RSDs for 50μL injections of 100μgmL−1 test solutions, while copper and stainless steel electrodes had %RSDs of 3–5 times higher than the nickel electrode. The role of the electrode geometries were evaluated previously-used 180° (co-linear) arrangement as well as for different configurations with the electrodes mounted at 90° with respect to each other, with the most intense optical emission responses found for the 180° geometry. Solution-based limits of detection (LOD) were found to be in the range of 0.44–0.93μgmL−1 for Ag, Cu, Mg, Ni, and Zn using the nickel electrode at the 180° geometry. Based on the use of 50μL injections, this represents absolute detection limits of 22–46ng. LODs were approximately an order of magnitude higher for the copper and stainless steel electrodes.
Source:Microchemical Journal, Volume 105
C. Derrick Quarles, Benjamin T. Manard, Carolyn Q. Burdette, R. Kenneth Marcus
The roles of the electrode material and geometry on the performance of the liquid sampling-atmospheric pressure glow discharge (LS-APGD) optical emission spectroscopy source are described. The LS-APGD source has been interfaced to a high resolution JY RF-5000 polychromator allowing for simultaneous multiple element detection. This LS-APGD source operates at currents of 20–60mA and solution flow rates of 0.1–0.4mLmin−1. A glow discharge is generated between the surface of the electrolyte test solution exiting a glass capillary and the end of a metallic counterelectrode. Described here is an evaluation of how the counterelectrode material identity (copper, nickel, and stainless steel) and the electrode configuration (geometry) influence the analyte emission responses for a test solution containing Ag, Cr, Cu, Mg, Ni, and Zn in 1M HNO3. Studies of the effect of liquid flow rates reveal that 0.3mLmin−1 provides optimal analyte emission responses as it relates to peak intensity, peak area, and peak widths. Use of nickel as the counterelectrode material provided the best reproducibility for analyte emission responses with 8.9–13.0%RSDs for 50μL injections of 100μgmL−1 test solutions, while copper and stainless steel electrodes had %RSDs of 3–5 times higher than the nickel electrode. The role of the electrode geometries were evaluated previously-used 180° (co-linear) arrangement as well as for different configurations with the electrodes mounted at 90° with respect to each other, with the most intense optical emission responses found for the 180° geometry. Solution-based limits of detection (LOD) were found to be in the range of 0.44–0.93μgmL−1 for Ag, Cu, Mg, Ni, and Zn using the nickel electrode at the 180° geometry. Based on the use of 50μL injections, this represents absolute detection limits of 22–46ng. LODs were approximately an order of magnitude higher for the copper and stainless steel electrodes.
Highlights
► Key operation parameters of the LS-APGD-OES microplasma source are studied. ► Electrode powering schemes effect emission and temporal responses of analytes. ► Ni counterelectrodes produce superior performance in all aspects of OES analysis. ► Collinear electrodes show better analytical performance than a 90° arrangement.Stability of arsenic speciation in fish muscle samples, under different storage and sample preparation conditions
23 October 2012,
09:32:38
Publication year:
2012
Source:Microchemical Journal, Volume 105
John Lewis, Penny Stokes, Nicola Brereton, Malcolm Baxter, Roy Macarthur
As part of a major survey investigating the levels of total and inorganic arsenic in a range of fish, shellfish and seaweed, a stability study was undertaken so as to ensure that the arsenic speciation profile in samples which had been stored for a number of months was likely to have remained unchanged. The potential for different sample preparation regimes to impact on arsenic speciation profiles was also assessed. The data from an initial time-based investigation suggested that the relative levels of inorganic arsenic did not vary over the 9month period of the study. However, as it had taken 10days to land, transport and process the fish material, prior to starting the stability study, a second study was undertaken, where the death-to-testing time was reduced to 3days. The data from this second study confirmed that from the first, showing that the speciation profile did not change, even during the early stages, when poorly controlled sample handling was potentially at its maximum. Data from the sample preparation experiment indicated that the preparation format, i.e., “wet” vs. “freeze-dried,” could influence the relative levels of inorganic arsenic, with less being measured in the latter format (0.14%±0.08%). Possible explanations were given, including microbiological activity within the “wet” samples. However, it was thought most likely to be due to analytical variation encountered when working at, or below, the methodological LOQ. It is hoped that this information will assist others regarding issues to be considered when performing similar studies.
Source:Microchemical Journal, Volume 105
John Lewis, Penny Stokes, Nicola Brereton, Malcolm Baxter, Roy Macarthur
As part of a major survey investigating the levels of total and inorganic arsenic in a range of fish, shellfish and seaweed, a stability study was undertaken so as to ensure that the arsenic speciation profile in samples which had been stored for a number of months was likely to have remained unchanged. The potential for different sample preparation regimes to impact on arsenic speciation profiles was also assessed. The data from an initial time-based investigation suggested that the relative levels of inorganic arsenic did not vary over the 9month period of the study. However, as it had taken 10days to land, transport and process the fish material, prior to starting the stability study, a second study was undertaken, where the death-to-testing time was reduced to 3days. The data from this second study confirmed that from the first, showing that the speciation profile did not change, even during the early stages, when poorly controlled sample handling was potentially at its maximum. Data from the sample preparation experiment indicated that the preparation format, i.e., “wet” vs. “freeze-dried,” could influence the relative levels of inorganic arsenic, with less being measured in the latter format (0.14%±0.08%). Possible explanations were given, including microbiological activity within the “wet” samples. However, it was thought most likely to be due to analytical variation encountered when working at, or below, the methodological LOQ. It is hoped that this information will assist others regarding issues to be considered when performing similar studies.
Highlights
► Chemical speciation often dictates the toxicity of an element. ► Sample storage conditions can affect metal speciation stability. ► Arsenic species are stable in fish flesh, under different sample preparation formats. ► Arsenic species are stable in fish flesh, under different sample storage conditions. ► Results prove data accuracy, obtained from long-term stored samples, in FSA survey.Levels of mercury and polychlorobiphenyls in commercial food in Siena Province (Tuscany, Italy) in the period 2001–2010
23 October 2012,
09:32:38
Publication year:
2012
Source:Microchemical Journal, Volume 105
Silvano Focardi
In this paper, the presence and amount of mercury and polychlorobiphenyls (PCBs) were determined in more than 1000 food items collected monthly in the period 2001–2010 in commercial food shops in Siena (Tuscany, Italy), in order to assess risk to humans due to food consumption. The overall results clearly show a strong difference in concentration of the two contaminants between foods from the terrestrial trophic web and those from the marine trophic web. Particular attention was paid to study the Mediterranean swordfish (Xiphias gladius) and bluefin tuna (Thunnus thynnus) because anthropic impact on these species is great due to their topmost position in trophic webs; thus it is very important to know their health status and evaluate their toxicity for humans. Many samples of bluefin tuna and swordfish show mercury levels higher than 0.5mg/kg f.w., which is the maximum level set by the European Commission (EC, Regulation n. 1881/2006) for most fish species. Taking into account the important nutritional contribution that fish makes to the diet, it is advisable that women of childbearing age, pregnant and breastfeeding women as well as young children select fish from a wide range of species, without giving undue preference to large predatory fish such as swordfish and tuna. In any case, it is interesting to note a significant decrease in levels of both mercury and PCBs in bluefin tuna and swordfish found in the Sienese market over the course of the past ten years.
Source:Microchemical Journal, Volume 105
Silvano Focardi
In this paper, the presence and amount of mercury and polychlorobiphenyls (PCBs) were determined in more than 1000 food items collected monthly in the period 2001–2010 in commercial food shops in Siena (Tuscany, Italy), in order to assess risk to humans due to food consumption. The overall results clearly show a strong difference in concentration of the two contaminants between foods from the terrestrial trophic web and those from the marine trophic web. Particular attention was paid to study the Mediterranean swordfish (Xiphias gladius) and bluefin tuna (Thunnus thynnus) because anthropic impact on these species is great due to their topmost position in trophic webs; thus it is very important to know their health status and evaluate their toxicity for humans. Many samples of bluefin tuna and swordfish show mercury levels higher than 0.5mg/kg f.w., which is the maximum level set by the European Commission (EC, Regulation n. 1881/2006) for most fish species. Taking into account the important nutritional contribution that fish makes to the diet, it is advisable that women of childbearing age, pregnant and breastfeeding women as well as young children select fish from a wide range of species, without giving undue preference to large predatory fish such as swordfish and tuna. In any case, it is interesting to note a significant decrease in levels of both mercury and PCBs in bluefin tuna and swordfish found in the Sienese market over the course of the past ten years.
Highlights
► The study was carried out on samples of several food items collected in Siena (Tuscany, Italy). ► We have analyzed mercury and polychlorobiphenyls (PCBs). ► The results show high levels of these two contaminants in food from marine origin. ► The results show a decrease in these two contaminants in food in last ten years. ► Pregnant and breastfeeding women must select fish from a wide range of species.Effect of the cooking procedure on the arsenic speciation in the bioavailable (dialyzable) fraction from seaweed
23 October 2012,
09:32:38
Publication year:
2012
Source:Microchemical Journal, Volume 105
Cristina García Sartal, María del Carmen Barciela-Alonso, Pilar Bermejo-Barrera
Seafood, including edible seaweed, contains high levels of arsenic. The intake of seaweed is a route to arsenic exposure. Due to the different toxic behaviors among arsenic species, speciation studies are a matter of vital importance to evaluate possible health risks for consumers. Most seaweeds are ingested after a heat treatment and these thermal procedures could lead to a change in arsenic speciation. In this work an arsenic speciation study of four edible seaweeds (Kombu, Wakame, Nori and Sea Lettuce) after cooking has been performed by anion-exchange HPLC connected to an ICP-MS for arsenical detection. Speciation studies were also carried out in the cooking waters of those samples. Powdered cooked seaweed was subjected to an in-vitro digestion procedure by using Piperazine-NN-bis (2-ethane-sulfonic acid) disodium (PIPES), as a buffer solution at a pH of 7.0 and dialysis membranes of 10kDa molecular weight cut off (MWCO). Dialyzable fractions were analyzed to identify the arsenic species that become bioavailable for human body functions. Total arsenic concentrations were found between 5.3 and 79.1μgg−1, 3.6–36.7μgg−1 and 1.8–54.3μgg−1 for raw and cooked seaweed, and cooking water, respectively. Total arsenic bioavailability percentages were 20%, 29%, 18% and 11% for cooked Kombu, Nori, Wakame and Sea lettuce, respectively. Results suggest that the heat treatment and the acidic environment and enzymes used in the in-vitro gastrointestinal digestion are not sufficient to produce a change in the arsenic species of the four seaweeds studied. Arsenic species are comparable in each seaweed before and after being cooked, their cooking water and dialysate. Arsenosugars were the main arsenic species found. As(III) species and arsenobetaine (AB) were only found in the Sea Lettuce sample. Glycerol sugar and sulfonate sugar were the most bioavailable species for cooked Kombu and Wakame. Phosphate sugar showed to be in highest proportion in the dialyzable fraction of Nori. AB and glycerol sugar became more bioavailable in the Sea Lettuce sample.
Source:Microchemical Journal, Volume 105
Cristina García Sartal, María del Carmen Barciela-Alonso, Pilar Bermejo-Barrera
Seafood, including edible seaweed, contains high levels of arsenic. The intake of seaweed is a route to arsenic exposure. Due to the different toxic behaviors among arsenic species, speciation studies are a matter of vital importance to evaluate possible health risks for consumers. Most seaweeds are ingested after a heat treatment and these thermal procedures could lead to a change in arsenic speciation. In this work an arsenic speciation study of four edible seaweeds (Kombu, Wakame, Nori and Sea Lettuce) after cooking has been performed by anion-exchange HPLC connected to an ICP-MS for arsenical detection. Speciation studies were also carried out in the cooking waters of those samples. Powdered cooked seaweed was subjected to an in-vitro digestion procedure by using Piperazine-NN-bis (2-ethane-sulfonic acid) disodium (PIPES), as a buffer solution at a pH of 7.0 and dialysis membranes of 10kDa molecular weight cut off (MWCO). Dialyzable fractions were analyzed to identify the arsenic species that become bioavailable for human body functions. Total arsenic concentrations were found between 5.3 and 79.1μgg−1, 3.6–36.7μgg−1 and 1.8–54.3μgg−1 for raw and cooked seaweed, and cooking water, respectively. Total arsenic bioavailability percentages were 20%, 29%, 18% and 11% for cooked Kombu, Nori, Wakame and Sea lettuce, respectively. Results suggest that the heat treatment and the acidic environment and enzymes used in the in-vitro gastrointestinal digestion are not sufficient to produce a change in the arsenic species of the four seaweeds studied. Arsenic species are comparable in each seaweed before and after being cooked, their cooking water and dialysate. Arsenosugars were the main arsenic species found. As(III) species and arsenobetaine (AB) were only found in the Sea Lettuce sample. Glycerol sugar and sulfonate sugar were the most bioavailable species for cooked Kombu and Wakame. Phosphate sugar showed to be in highest proportion in the dialyzable fraction of Nori. AB and glycerol sugar became more bioavailable in the Sea Lettuce sample.
Highlights
► Qualitative arsenic speciation study in seaweeds ► Characterization of arsenic species in edible seaweeds after cooking ► Arsenic speciation study in dialysates of cooked seaweedsICP-AES determination of minor and major elements in Cornelian cherry (Cornus mas L.) after microwave assisted digestion
23 October 2012,
09:32:38
Publication year:
2012
Source:Microchemical Journal, Volume 105
Iva Juranović Cindrić, Michaela Zeiner, Martina Krpetić, Gerhard Stingeder
Inductively coupled plasma atomic emission spectrometry (ICP-AES) was used for the determination of minor and major elements present in Cornelian cherry (Cornus mas L.), as this fruit and its preservatives may be considered as important nutritional supplements. Prior to ICP-AES measurement, the samples were digested in a microwave assisted digestion system. The ICP-AES method was validated and optimized for the determination of selected elements in Cornelian cherry. The accuracy of the method as estimated through by spiking experiments was satisfactory, the recoveries obtained after microwave digestions in whole fruit (A), mesocarp (B) seed (C), and juice ranged from 84–123%, 74–115% 82–124%, and from 83–116% respectively. For microwave assisted digested Cornelian cherry samples of whole fruit (A), mesocarp (B) and seeds (C) the following limits of detection were obtained <2ng/g for Al, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, Zn, Mg, and K, moderate 2–10ng/g for B, and Ca. The highest LODs were obtained only for Al in mesocarp (B) and seeds (C) compared with whole fruit (A). For microwave assisted digested Cornelian cherry juice the limits of detection were in the range 0.04–0.108μg/L. The precision of the method was evaluated using the standard deviation, RSD, of repeated determinations of the analytes and for all elements RSD ranged from 0.5 to 7% except for Na 12%. The intermediate precision (< 4.8%), the day-to-day reproducibility (< 6.8%), and the overall uncertainty of measurement (approx. 4–10%) for all elements analyzed demonstrated the good applicability of the chosen microwave assisted digestion procedure. Regarding potentially toxic elements, Cu and Pb are below 4μg/g in the whole berry, Cr and Cd were not even detected.The order of magnitude of the concentrations for the elements found in whole fruit (whole fruit, A) and seed (C) is found to be similar for most of the elements of interest, namely in μg/g: 2.52 and 6.0 B, 2074.4 and 3971.8 Ca, 2.4 and 2.4 Cu, 7.8 and 4.1 Fe, 4019 and 3288 K, 288 and 237 Mg, 1.65 and 3.1 Mn, 22.9 and 41 Na, 9.0 and 6.9 Ni, 2.9 and 3.3 Pb, 6.9 and 12.5 Sr, respectively. In Cornelian cherry juice the content of Al, Ba, Cd, Cr, Cu, Mn, Pb, and Sr were below the limits of detection (0.06, 0.07, 0.07, 0.006, 0.01, 0.042, 0.056, 0.04 and 0.009μg/L, respectively). The content of minor elements was 0.135 Fe, 0.163 Ni, 0.828 Zn and 1.47mg/L B. The concentrations of major elements were 11.3 Na, 51.7 Ca, 94.3Mg and 1326mg/LK.
Source:Microchemical Journal, Volume 105
Iva Juranović Cindrić, Michaela Zeiner, Martina Krpetić, Gerhard Stingeder
Inductively coupled plasma atomic emission spectrometry (ICP-AES) was used for the determination of minor and major elements present in Cornelian cherry (Cornus mas L.), as this fruit and its preservatives may be considered as important nutritional supplements. Prior to ICP-AES measurement, the samples were digested in a microwave assisted digestion system. The ICP-AES method was validated and optimized for the determination of selected elements in Cornelian cherry. The accuracy of the method as estimated through by spiking experiments was satisfactory, the recoveries obtained after microwave digestions in whole fruit (A), mesocarp (B) seed (C), and juice ranged from 84–123%, 74–115% 82–124%, and from 83–116% respectively. For microwave assisted digested Cornelian cherry samples of whole fruit (A), mesocarp (B) and seeds (C) the following limits of detection were obtained <2ng/g for Al, Ba, Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, Sr, Zn, Mg, and K, moderate 2–10ng/g for B, and Ca. The highest LODs were obtained only for Al in mesocarp (B) and seeds (C) compared with whole fruit (A). For microwave assisted digested Cornelian cherry juice the limits of detection were in the range 0.04–0.108μg/L. The precision of the method was evaluated using the standard deviation, RSD, of repeated determinations of the analytes and for all elements RSD ranged from 0.5 to 7% except for Na 12%. The intermediate precision (< 4.8%), the day-to-day reproducibility (< 6.8%), and the overall uncertainty of measurement (approx. 4–10%) for all elements analyzed demonstrated the good applicability of the chosen microwave assisted digestion procedure. Regarding potentially toxic elements, Cu and Pb are below 4μg/g in the whole berry, Cr and Cd were not even detected.The order of magnitude of the concentrations for the elements found in whole fruit (whole fruit, A) and seed (C) is found to be similar for most of the elements of interest, namely in μg/g: 2.52 and 6.0 B, 2074.4 and 3971.8 Ca, 2.4 and 2.4 Cu, 7.8 and 4.1 Fe, 4019 and 3288 K, 288 and 237 Mg, 1.65 and 3.1 Mn, 22.9 and 41 Na, 9.0 and 6.9 Ni, 2.9 and 3.3 Pb, 6.9 and 12.5 Sr, respectively. In Cornelian cherry juice the content of Al, Ba, Cd, Cr, Cu, Mn, Pb, and Sr were below the limits of detection (0.06, 0.07, 0.07, 0.006, 0.01, 0.042, 0.056, 0.04 and 0.009μg/L, respectively). The content of minor elements was 0.135 Fe, 0.163 Ni, 0.828 Zn and 1.47mg/L B. The concentrations of major elements were 11.3 Na, 51.7 Ca, 94.3Mg and 1326mg/LK.
Highlights
► Popularization of Cornelian cherry and the potential of European cultivars as a new promising fruit species. ► The elemental content of berries influences the quality of fruit, including organoleptic characteristics and stability. ► Metal concentrations were determined using ICP-AES. ► The knowledge of the mineral contents of berries is important from the toxicological point of view. ► This study is important confirms the importance of Cornelian cherry as nutritional supplement.Determination of mercury in size fractionated road dust samples by flow injection-cold vapor-atomic absorption spectrometry
23 October 2012,
09:32:38
Publication year:
2012
Source:Microchemical Journal, Volume 105
Agustín Londonio, Fabián Fujiwara, Raúl Jiménez Rebagliati, Darío Gómez, Patricia Smichowski
An investigation was carried out to explore the effect of citric, hydrochloric, oxalic and tartaric acids on mercury vapor generation in a flow injection system in conjunction with atomic absorption spectrometry detection (CV-AAS) for its determination in road dust samples. Samples were collected in Buenos Aires (Argentina) during two months at 15 sites grouped in five zones with different urban characteristics and traffic profile. They were sieved in four fractions (with the following particle diameter (d): A: d <37μm, B: 37< d <50μm, C: 50< d <75μm, and D: 75< d <100μm) before Hg determination. The operating conditions (chemical and physical parameters) and the type and concentration of the acids studied (citric, hydrochloric, oxalic and tartaric) were assessed for the efficient generation of Hg. The interfering effect of metals and metalloids, present as minor and major concentrations in road dust, on Hg signal were evaluated using the four acids. Hydrochloric acid resulted to be the most convenient reaction medium in terms of sensitivity but a suitable control of interferences was not reached. For a complex matrix such as road dust, the best control of interferences was achieved when oxalic acid was tested, even when lower Hg signal was obtained in comparison with HCl. The detection limit (3σ criterion) turned out to be 0.3ngg−1. For checking accuracy, two certified reference materials were analyzed and results were in good agreement with certified values. Mercury concentrations in road dust ranged between 0.1μgg−1 and 4.6μgg−1 and the mean concentration value resulted to be 1.09μgg−1. In the four fractions, Hg concentrations (μgg−1) varied as follows: Fraction A (<0.0003–3.51); Fraction B (0.49–4.63); Fraction C (0.20–1.36) and Fraction D (0.16–1.88). The procedure is simple, rapid and robust.
Source:Microchemical Journal, Volume 105
Agustín Londonio, Fabián Fujiwara, Raúl Jiménez Rebagliati, Darío Gómez, Patricia Smichowski
An investigation was carried out to explore the effect of citric, hydrochloric, oxalic and tartaric acids on mercury vapor generation in a flow injection system in conjunction with atomic absorption spectrometry detection (CV-AAS) for its determination in road dust samples. Samples were collected in Buenos Aires (Argentina) during two months at 15 sites grouped in five zones with different urban characteristics and traffic profile. They were sieved in four fractions (with the following particle diameter (d): A: d <37μm, B: 37< d <50μm, C: 50< d <75μm, and D: 75< d <100μm) before Hg determination. The operating conditions (chemical and physical parameters) and the type and concentration of the acids studied (citric, hydrochloric, oxalic and tartaric) were assessed for the efficient generation of Hg. The interfering effect of metals and metalloids, present as minor and major concentrations in road dust, on Hg signal were evaluated using the four acids. Hydrochloric acid resulted to be the most convenient reaction medium in terms of sensitivity but a suitable control of interferences was not reached. For a complex matrix such as road dust, the best control of interferences was achieved when oxalic acid was tested, even when lower Hg signal was obtained in comparison with HCl. The detection limit (3σ criterion) turned out to be 0.3ngg−1. For checking accuracy, two certified reference materials were analyzed and results were in good agreement with certified values. Mercury concentrations in road dust ranged between 0.1μgg−1 and 4.6μgg−1 and the mean concentration value resulted to be 1.09μgg−1. In the four fractions, Hg concentrations (μgg−1) varied as follows: Fraction A (<0.0003–3.51); Fraction B (0.49–4.63); Fraction C (0.20–1.36) and Fraction D (0.16–1.88). The procedure is simple, rapid and robust.
Highlights
► We determined by the first time Hg on road dust samples collected in Buenos Aires. ► We compared four acid media for Hg vapor generation. ► The effect of each acid media on the control of interferences was assessed. ► The use of organic acids for Hg vapor generation is the most correct procedure from the environmental point of view. ► This work reports by the first time concentrations of Hg in Buenos Aires road dust as well as information on its origin.Microanalytical investigation of nematodes
23 October 2012,
09:32:38
Publication year:
2012
Source:Microchemical Journal, Volume 105
Zoltán Sávoly, Péter Nagy, Károly Havancsák, Gyula Záray
The chemical characterization of individual free-living nematodes is a challenge due to their small size and correspondingly, their low dry mass (1–3μg). The concentrations of minor (S, P, Ca, K) and trace elements (Fe, Zn, Cu, Ni, and Mn) of individual specimens (Xiphinema Vuittenezi) were determined by total reflection X-ray fluorescence (TXRF) spectrometry following a two step sample preparation procedure. The mean concentrations of minor and trace elements changed in the range of 1–4 and 0.01–0.4ng/μg, respectively. The relative standard deviation varied between 9.4 and 25.3% which was influenced not only by the analytical procedure but also by the biological deviations among the eleven investigated specimens. The stress effect caused by CuSO4 treatment resulted in significant change in the nematodes only in their Zn content. In the lack of certified reference material, the TXRF method was checked by inductively coupled plasma mass spectrometry (ICP-MS) analyzing solutions of 100 digested nematodes. The carbon and nitrogen content of nematodes was also measured by total C/N analyzer and their ratio amounted to 4.78±0.31 which is lower than the values published for the bacterial or fungal feeding ones. The way of copper uptake was investigated by scanning electron microscopy (SEM). Nematode treated with copper-nitrate was pecked out at the mid-body using focused ion beam (FIB) technique. In order to preserve the cross-section to be investigated, platinum coating was applied prior to the FIB operation. Energy dispersive X-ray analysis was performed along the cross-section measuring the distribution of platinum, sulfur and copper. It has been found that the sulfur and copper distributions were fairly similar following the copper treatment, and these elements had the highest concentration in the cuticle.
Source:Microchemical Journal, Volume 105
Zoltán Sávoly, Péter Nagy, Károly Havancsák, Gyula Záray
The chemical characterization of individual free-living nematodes is a challenge due to their small size and correspondingly, their low dry mass (1–3μg). The concentrations of minor (S, P, Ca, K) and trace elements (Fe, Zn, Cu, Ni, and Mn) of individual specimens (Xiphinema Vuittenezi) were determined by total reflection X-ray fluorescence (TXRF) spectrometry following a two step sample preparation procedure. The mean concentrations of minor and trace elements changed in the range of 1–4 and 0.01–0.4ng/μg, respectively. The relative standard deviation varied between 9.4 and 25.3% which was influenced not only by the analytical procedure but also by the biological deviations among the eleven investigated specimens. The stress effect caused by CuSO4 treatment resulted in significant change in the nematodes only in their Zn content. In the lack of certified reference material, the TXRF method was checked by inductively coupled plasma mass spectrometry (ICP-MS) analyzing solutions of 100 digested nematodes. The carbon and nitrogen content of nematodes was also measured by total C/N analyzer and their ratio amounted to 4.78±0.31 which is lower than the values published for the bacterial or fungal feeding ones. The way of copper uptake was investigated by scanning electron microscopy (SEM). Nematode treated with copper-nitrate was pecked out at the mid-body using focused ion beam (FIB) technique. In order to preserve the cross-section to be investigated, platinum coating was applied prior to the FIB operation. Energy dispersive X-ray analysis was performed along the cross-section measuring the distribution of platinum, sulfur and copper. It has been found that the sulfur and copper distributions were fairly similar following the copper treatment, and these elements had the highest concentration in the cuticle.
Highlights
► Elemental analysis of individual plant parasitic nematodes by TXRF spectrometry. ► Determination of cross sectional distribution of elements by focused ion beam-SEM. ► Bulk analysis of 100 nematodes by ICP-MS following a microwave-assisted digestion.Separation and preconcentration of trace amounts of Cr(III) ions on ion imprinted polymer for atomic absorption determinations in surface water and sewage samples
23 October 2012,
09:32:38
Publication year:
2012
Source:Microchemical Journal, Volume 105
Barbara Leśniewska, Beata Godlewska-Żyłkiewicz, Agnieszka Z. Wilczewska
A new type of Cr(III)-imprinted polymer was prepared from Cr(III)–pyrrolidinedithiocarbamate complex, acrylamide functional monomer and ethylene glycol methacrylate cross-linking agent. The polymer was employed as a selective solid phase extraction material for separation of trace amounts of Cr(III) ions under dynamic conditions. The effects of the conditioning of imprinted polymer, conditions of Cr(III) retention and elution were studied. It was found that Cr(III) ions can be retained on tested sorbent with high efficiency and repeatability (87%, RSD=3.2%) from a solution of pH 3.50–4.75. The quantitative elution of analyte was obtained with 0.2molL−1 nitric acid solution. The retention of Cr(VI) ions on the polymer in the studied pH range (1.0–7.0) was at the level of 10–15%. The selectivity of prepared sorbent towards Cr(III) ions was good in the presence of Cu(II) and Ni(II) ions and worse in the presence of Fe(III) ions at a concentration higher than 0.5μgmL−1. The detection limit for Cr(III) obtained by electrothermal atomic absorption spectrometry (ETAAS) after preconcentration of 40mL of sample on the polymer was 0.018ngmL−1. The developed separation method was successfully applied to the ETAAS determination of trace amounts of Cr(III) in tap and river water and municipal sewage.
Source:Microchemical Journal, Volume 105
Barbara Leśniewska, Beata Godlewska-Żyłkiewicz, Agnieszka Z. Wilczewska
A new type of Cr(III)-imprinted polymer was prepared from Cr(III)–pyrrolidinedithiocarbamate complex, acrylamide functional monomer and ethylene glycol methacrylate cross-linking agent. The polymer was employed as a selective solid phase extraction material for separation of trace amounts of Cr(III) ions under dynamic conditions. The effects of the conditioning of imprinted polymer, conditions of Cr(III) retention and elution were studied. It was found that Cr(III) ions can be retained on tested sorbent with high efficiency and repeatability (87%, RSD=3.2%) from a solution of pH 3.50–4.75. The quantitative elution of analyte was obtained with 0.2molL−1 nitric acid solution. The retention of Cr(VI) ions on the polymer in the studied pH range (1.0–7.0) was at the level of 10–15%. The selectivity of prepared sorbent towards Cr(III) ions was good in the presence of Cu(II) and Ni(II) ions and worse in the presence of Fe(III) ions at a concentration higher than 0.5μgmL−1. The detection limit for Cr(III) obtained by electrothermal atomic absorption spectrometry (ETAAS) after preconcentration of 40mL of sample on the polymer was 0.018ngmL−1. The developed separation method was successfully applied to the ETAAS determination of trace amounts of Cr(III) in tap and river water and municipal sewage.
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