Determination of trace amounts of metals in saline water by energy dispersive XRF using the NaDDTC preconcentration

A simple method for the determination of trace concentrations of metals in saline water is described. The analytical procedure involves the separation of metal ions of Cu, Zn, Hg and Fe by precipitation with diethyldithiocarbamate (DDTC). The radioisotope X-ray fluorescence method using Si(Li) detector has been applied for the determination of metal ions closed in the DDTC deposition.     

Determination of trace metal complexes by natural organic and inorganic ligands in coastal seawater.

It is well-documented that organic compounds form strong complexes with most metals in aquatic systems, and that seawater is a complex medium which contains a large variety of organic and inorganic ligands, including colloidal matter. We suggest that most trace metals are complexed in seawater and that some inorganic metals complexes are either labile or not stable. In contrast, metal-organic complexes are often stable and need various and specific treatments to be dissociated. In this paper we try to illustrate a good tendency of some trace metals to be complexed by organic ligands in seawater. A solid-phase extraction method was applied using a C18 column as a resin that is able to separate metals complexed by neutral organic ligands, and the chelamine resin to separate metal species that are present as labile inorganic complexes. The determination of total dissolved metal concentrations was achieved by formatting a metal-8-hydroxyquinoline complex, followed by adsorption on C18 columns and ICP-AES analysis.     

Continuous sonoassisted digestion coupled to flow injection minicolumn separation for the determination of total and labile Cu and Fe in fresh waters by flame atomic absorption spectrometry

An automatic on-line system is developed for the trace determination of copper and iron species in fresh waters by flame atomic absorption spectrometry using only 5 and 2?mL of sample, for copper and iron determination, respectively. This system, which includes a home-made minicolumn of commercially available resin containing aminomethylphosphonic acid functional groups (Chelite P), comprises two operational modes. The first, used for the determination of the dissolved labile fraction (free copper and iron ions and their weak complexes) is based on the elution of this fraction from a minicolumn containing the chelating resin loaded in-situ with the sample. The second mode is used for the determination of total trace copper and iron concentrations. This last mode is based on the retention/preconcentration of total metals on the Chelite P resin after on-line sonoassisted digestion of water samples acidified with nitric acid (0.5?mol?L^?1 final concentration) to break down metal organic complexes present in fresh waters as river waters. The figures of merit for copper and iron determination in both fractions are given and the obtained values are discussed. The analytical method was characterized and the limit of detection and limit of quantification for the two metals were 0.5 and 1.6?µg?L^?1 for Cu and 2.3 and 6.1?µg?L^?1 for Fe, respectively. The repeatability, expressed as relative standard deviation, was in the range 1.0–2.1%. The speciation scheme was applied to the analysis of river surface water samples collected in Galicia (Northwest, Spain).     

Determination of copper and nickel in vegetable oils by direct sampling graphite furnace atomic absorption spectrometry

The quality of food products has been receiving great attention due to its influence on human nutrition and health. In this sense, the determination of trace metals in foods has turned an important field on food analysis. Concerning vegetable oils, its metal trace composition is an important criterion for the assessment of their quality once it is known that trace metals affect their rate of oxidation, influencing freshness, keeping properties as well as storage. In the present work an analytical method which enables the direct determination of Cu and Ni in vegetable oils by graphite furnace atomic absorption spectrometry (GFAAS), using a “solid” sample strategy is presented: in nature, samples are directly weighed on the graphite platform boat and inserted in the graphite tube. An adequate temperature program permitted the calibration by external aqueous analytical curves. Good concordance between the proposed procedure and EPA procedures was found in the analysis of real samples. Limits of detection of 0.001 and 0.002 μg g⁻¹ were found for Cu and Ni, respectively, in the original samples, and they were comfortably below the concentrations found.     

Determination of trace metals in the River Ye?il?rmak sediments in Tokat, Turkey using sequential extraction procedure

Sequential extraction procedure (acid extractable, reducible, oxidizable, and residual) proposed by BCR was applied for the determination of trace metals in the River Yesilirmak sediments, Tokat, Turkey. The determination of trace metals in sediment samples was performed by flame atomic absorption spectrometry. The proposed method showed satisfactory recovery, detection limits and standard deviation for trace metals determination in sediment samples. Generally, most of the elements were found in the oxidizable and residual fractions. The total concentrations of trace metals analyzed were found to be (mg/kg) Cu: 37.9, Mn: 392.2, Zn: 126.2, Fe: 3726, and Pb: 29.6, respectively. Results obtained are in agreement with data reported in the literature.     

Flow injection flame atomic absorption determination of Cu, Mn and Zn partitioning in seawater by on-line room temperature sonolysis and minicolumn chelating resin methodology

A flow-injection system is developed for Cu, Mn and Zn partitioning in seawater by flame atomic absorption spectrometry. The first approach is where the trace metal species are fractionated in situ, but analysis is performed by using a flow injection manifold in the laboratory. This operational mode is used for the determination of the dissolved labile metallic fraction and is based on the elution of this fraction from a minicolumn packed with a chelating resin containing iminodiacetic acid groups (Serdolit Chelite Che) loaded in situ with the sample. The second is used for the determination of total dissolved concentrations of trace metals. This last mode is based on the retention/preconcentration of total dissolved metals on the chelating resin after on-line sonolysis of seawater samples acidified with diluted nitric acid to breakdown the metal-organic matter complexes. The figures of merit for Cu, Mn and Zn determinations in both fractions are given and the obtained values are discussed. The fractionation scheme is applied to the analysis of coastal seawater samples collected in Galicia (Northwest, Spain). The results of fractionation showed that Mn and Zn are mainly in the labile fraction, while Cu was mainly present in the organic fraction.     

INAA and PIXE characterization of heavy metals and rare earth elements emissions from phosphorite handling in harbours

Harbour activities such as loading, unloading and transport of materials may be an important source of Atmospheric Particulate Matter (APM). Depending on the materials, the type of operation and the meteorological conditions, these activities may have an impact on the levels of APM around harbour areas. The aim of this work was to characterize the emissions of dust providing from operations associated with phosphorite handling in harbours. Phosphorite is a non-detrital sedimentary rock which contains high amounts of phosphate bearing minerals and is used for the production of phosphorous based fertilizers. When handled in harbours frequently cause visual and environment impacts due to its physical and chemical characteristics. The techniques Instrumental Neutron Activation Analysis and Particle Induced X-ray Emission were applied as sensitive analytical tools for the determination of heavy metals and rare earth elements in phosphorite and in the APM sampled in the harbour during the unloading operations. Results showed that manipulation of phosphorite during harbour operations resulted in high emissions of particles, principally from the coarse fraction. These emissions were enriched in rare earth elements and heavy metals and were very affected by the provenience of the phosphorite.     

Use of atomic absorption spectrometry for the determination of metals in sediments in south-west Louisiana

The relatively recent introduction of atomic absorption spectrometry has produced a rapid and relatively inexpensive method for the determination of metal concentrations in a wide variety of samples. One such application is in the determination of metal concentrations in soils and sediments. Soils and sediments represent concentrated reservoirs for these metals that serve as sinks for introduced trace metals or can become environmental sources. The coastal zone of Louisiana provides a ‘living laboratory’ to investigate the mechanisms of transport, deposition, and dissolution of trace metals into this fragile environment. Investigations done in the coastal zone have found trace metals tend to concentrate near pollution inputs and sources and have not migrated to or significantly impacted the coastal zone of Louisiana. Common trace metals determined and their range of concentrations in coastal soil and sediments are chromium (10–30 ppm), copper (10–25 ppm), iron (0.6–2.1%), manganese (200–600 ppm), nickel (6–20 ppm), lead (8–20 ppm), and zinc (30–55 ppm).     

The Application of Microelectrodes for the Measurements of Trace Metals in Water

Abstract

The analytical approaches for the determination of trace concentrations of heavy metals in aquatic systems are briefly introduced. A detailed review on the recent advances of microelectrodes is presented, including the definitions, types, advantages, theory, and fabrication of microelectrodes. The application of microelectrodes on the measurements of trace metals in water is focused on the voltammetric‐, potentiometric‐, and in situ electrochemical sensors.     

Application of a Cation-Exchange Membrane to Determine Cations of Trace Metals in River Water

Donnan-membrane-equilibrium graphite-furnace atomic-absorption spectrophotometry (DME-GFAAS) has been developed to determine cations of trace metals in river water. The method employs a cation-exchange membrane to separate metal cations from their complexes; both total and cationic forms of metals were determined by means of GFAAS. The sensitivity of the method for the measurement of trace metal cations is determined by the detection limits of GFAAS for the metals of interest. Comparable concentrations of metal cations in water from NBS and from the Erhjen river were obtained between the DME-GFAAS and calculated (WATEQ4F) methods, indicating that the developed method is promising for natural fresh waters. The effect of pH on the distribution of metal cation in the NBS river water is significant for Cu and Pb; concentrations of these cations increase with decreasing pH. However, the concentrations of Cd and Zn cations do not vary with pH except that the concentration of the Zn cation decreases significantly as the pH value increases beyond 9. The method was applied to measure the capacity of complexing Cu in Chung-Lu river water, which was estimated to be 2.3 μM.     

Trace metal speciation in European River waters

Within an EC-study of the relationship between the chemistry of the aquatic system and resulting toxicological effects of heavy metals on micro-organisms, the speciation of trace metals is being assessed. The set-up of a speciation scheme is described, in which surface water is characterised in terms of total metal concentrations, nutrients, general parameters like DOC, pH and conductivity, metal binding properties and in which biologically relevant metal fractions are determined.     

An intercomparison exercise for trace metal monitoring in oxygen-rich and anoxic Baltic waters

Seawater samples for a laboratory intercomparison of trace metal concentrations (Mn, Fe, Ni, Cu, Cd, Pb) in the dissolved (<0.4 μm filtered) and particle-bound phases as well as total and reactive Hg were collected in the Gotland Basin, a region in the Baltic Sea with trace metal gradients in the halocline and the redox boundary. Two laboratories took part in this exercise, each laboratory analysing samples from two vertical profiles collected using ”clean” sampling techniques. The hydrographic and hydrochemical situation was determined to characterise the water column and help interpret the results. An estimation of the conformity of the two laboratories was performed by comparing the results with international intercalibration exercises and certified reference materials. For all metals the characteristic vertical distribution and the concentration range of the data were comparable to other results published for the region. The concentration differences in the amount contents of Mn, Fe, Ni, Cu, Cd, Pb and Hg determined between both laboratories were better than the confidence intervals given by an ICES (International Council for the Exploration of the Sea) international comparison exercise for Baltic waters. Differences for Ni in the anoxic water body are attributed to the sulphidic matrix and their influence on the different methods used by the laboratories. For Pb and Hg the concentrations were near the detection limit of our methods, low level contamination was possibly responsible for the concentration differences. Small differences for dissolved Mn were attributed to different sampling techniques. We conclude that sampling and sample handling are still weak links in the trace metal analysis of anoxic seawater and that the analytical methods we used for this exercise are satisfactory for the accurate determination of Cd, Cu, Pb, Mn, Fe, and also for studying biogeochemical cycling of these trace metals in oxygen-rich and anoxic water bodies. Received: 8 February 2001 Accepted: 8 August 2001     

X-ray determination of traces of hafnium in zirconium metal or traces of zirconium in hafnium metal after separation by ion exchange

A method is proposed for the determination of traces of hafnium in zirconium metal or zirconium in hafnium metal. The trace metals are first separated from the matrix metals on an ion-exchange column and then determined by X-ray analysis.     

Influence on elemental status by hip-endoprostheses

For many clinical purposes various artificial devices are applied, which contact human tissue and can thus cause adverse reactions between prosthetic surfaces and body components. Of the many materials applied for orthopaedic joint replacements the most common are cobalt-chromium-molybdenum alloys. In these cases considerable amounts of cobalt-chromium-molybdenum wear particles are released from the prostheses which have to be regarded as a cause of long-time problems for the patient.Since these particles are dissolved in body fluids of the surrounding area they are distributed in the whole body via blood. Elevated metal concentrations have been found in blood and urine of persons with endoprostheses. Partly the metals are excreted via urine, but to some extend they accumulate in different organs.Therefore this study dealt with the development of an analytical method for the determination of seven relevant trace elements, namely Al, Co, Cr, Mo, Nb, Ni, and Ti in nine kinds of human tissue (brain, heart, kidney, liver, lung, muscle, lymphatic nodes, spleen, body fat) starting with drawing of the sample, sample work up and finally analysis by means of atomic spectrometry. The optimized method was then applied to determine the metal contents in organs of persons (post mortem) with total hip replacements with metal on metal bearing surfaces. Comparison of the data obtained with those of persons without hip-endoprostheses shows that brain and lung are the main targets for elemental accumulation in persons with hip-endoprostheses. Mo and Nb represent the elements with the highest tendency to be accumulated.     

The application of an argon/nitrogen inductively-coupled plasma to the analysis of organic solutions

A 4-kW argon/nitrogen inductively-coupled plasma (ICP) is used for multielement trace determinations in organic solutions. After optimization of the pneumatic nebulizer and ICP parameters, trace determinations at sub-mug/ml concentrations with relative standard deviations of 1% are possible. The first application described is the determination of a series of metals (Cd, Cu, Fe, Mn, Zn) after their isolation from the sample matrix by extraction of the ammonium pyrrolidinedithiocarbamate complexes into methyl isobutyl ketone. Alkali and alkaline-earth metal salts at 50-g/l. concentrations do not affect the method, which can be applied to trace determinations in industrial waste waters having high salt contents. The second application is the multielement analysis of oils. The samples are diluted 1:10 with xylene, and the detection limits for Al, Cu, Fe, Mg, Mn, Si and Zn are in the sub-mu/g range. The superior detection power of spectrographic ICP methods in comparison with photoelectric techniques using a monochromator and a polychromator is discussed. Oils of different viscosities can be analysed with use of the same calibration graphs. From experiments with a computer-controlled polychromator with background measurement facilities, it is concluded that the accuracy is improved if background measurements are made at wavelengths near the analytical lines, for each sample independently.     

Analytical possibilities of microelectrode use for stripping voltammetry

The analytical utility of microelectrodes for stripping voltammetry is discussed from several points of view. The application of microelectrodes for microanalysis is demonstrated using a novel capillary flow injection system. Heavy metals at g l^–1 concentrations have been determined in l-samples. The influence of electrode size and convection during the deposition period of anodic stripping voltammetry on the reproducibility of trace metal determination was studied for various types of electrodes. In the case of mercury film microelectrodes, the precision can be improved if the accumulation of the analyte is performed under quiescent conditions. Practical examples of stripping voltammetry with microelectrodes such as copper determination in whisky and trace metal measurements in drinking water are given.     

A high-throughput solid-phase extraction microchip combined with inductively coupled plasma-mass spectrometry for rapid determination of trace heavy metals in natural water

Herein, a hyphenated system combining a high-throughput solid-phase extraction (htSPE) microchip with inductively coupled plasma-mass spectrometry (ICP-MS) for rapid determination of trace heavy metals was developed. Rather than performing multiple analyses in parallel for the enhancement of analytical throughput, we improved the processing speed for individual samples by increasing the operation flow rate during SPE procedures. To this end, an innovative device combining a micromixer and a multi-channeled extraction unit was designed. Furthermore, a programmable valve manifold was used to interface the developed microchip and ICP-MS instrumentation in order to fully automate the system, leading to a dramatic reduction in operation time and human error. Under the optimized operation conditions for the established system, detection limits of 1.64–42.54 ng L⁻¹ for the analyte ions were achieved. Validation procedures demonstrated that the developed method could be satisfactorily applied to the determination of trace heavy metals in natural water. Each analysis could be readily accomplished within just 186 s using the established system. This represents, to the best of our knowledge, an unprecedented speed for the analysis of trace heavy metal ions.     

Bestimmung von Metallen in Flußschlämmen mit Hilfe der Röntgenfluorescenz. Bedeutung für die Praxis

The occurrence of metals in the sediments of the Rhine basin was investigated with the aid of X-ray fluorescence. In addition to trace metals such as zirconium, strontium and rubidium which are encountered in non-varying concentrations, the heavy metals copper, lead and, in particular, zinc were found to occur in concentrations that vary considerably from one region to the other. Concentrations beyond the normal background limits are due to influent waste water. Besides the easy determination of metal traces, X-ray fluorescence permits also deductions on the density and, consequently, the mineralogical composition of the sediments.     

Trace metals in human lung as determined by neutron activation analysis of bronchoalveolar lavage

The possibility to use the bronchoalveolar lavage (BAL) in combination with analytical methods for trace metal analysis such as neutron activation analysis (NAA), inductively coupled plasma (ICP) and electrothermal atomic absorption spectroscopy (ETASS) for the determination of trace elements in the lung of living subjects has been investigated. In particular more than 30 elements have been determined: (1) in physiological solutions used for bronchopulmonary lavage (blank values) (2) in BALs of volunteer patients (unexposed subjects) (3) in BALs of occupational workers affected by pulmonary fibrosis as diagnosed by clinical methods (exposed subjects). Although the number of cases with metal exposure studied by NAA-BAL method is too limited to draw definitive conclusions the results suggest that the procedure can provide interesting qualitative information on metals which would be actually retained in the lung tissue. However, although the method may become of importance when integrated with clinical examinations further investigations are necessary to establish qualitative relations between trace metal levels determined in the BAL and the total elemental content of the lung tissue.     

Accurate determination of the noble metals II. Determination methods

As was shown in the first part of this contribution, accurate analytical determination of the noble metals in rocks, ores and alloys needs a sophisticated sample pretreatment prior to the final determination step of the preconcentrated elements. For this many instrumental and classical methods are available, the choice of which is usually dictated by levels of precious metal to be handled, nature of sample matrix and availability of the instruments. For trace levels (μg/g range) flame atomic absorption and inductively coupled plasma (ICP) emission spectrometry can be used. ICP emission is favoured because of ease of multi-element operation. At the sub-μg/g level furnace atomic absorption and nuclear techniques (mainly neutron activation) are favoured. Minor and % concentrations are best handled by X-ray fluorescence. The use of standard reference samples and internal and external laboratory control schemes are essential to the accurate determination of precious metals.