Sediment Certified Reference Materials Research Articles

Synthesis and Analytical Applications of Uranyl Ion Imprinted Polymer Particles

Uranyl ion imprinted polymer particles were prepared by the copolymerization of styrene monomer and a crosslinking agent divinyl benzene in the presence of -5,7-dichloroquinoline-8-ol-4-vinyl pyridine ternary complex as template where in is the imprint ion in presence of 2,2′-azo-bis-isobutyronitrile as initiator. The Uranyl ion was removed from the polymer particles by leaching with 1:1 HCl, which leaves cavities in the polymer particles. The leached polymer particles preconcentrate ion from dilute aqueous and synthetic seawater solutions. Further, these particles find use in the separation of ion from various bivalent, trivalent, and tetravalent, inorganic ions. The accuracy of the developed enrichment procedure was tested by analyzing marine sediment certified reference material supplied by National Research Council (NRC), Canada. Further, the developed procedure has been successfully employed to analyze real soil and sediment samples.

Improvement of measurement precision of SPME-GC/MS determination of tributyltin using isotope dilution calibration.

A unique approach was developed to improve the precision of quantification of tributyltin (TBT) in sedimentsby solid phase microextraction (SPME) using isotope dilution GC/MS. The precision of the analytical technique was initially evaluated using standard calibration solutions. In selective ion monitoring (SIM) mode, the relative standard deviation (RSD) obtained for TBT based on peak area response was 18% (n = 11). When an internal standard, tripropyltin (TPrT), was used, the RSD decreased to 12%. A significant improvement in the precision using SPME was noted when a 117Sn-enriched TBT spike was employed; the RSD decreased 4-fold to 3%. Detection limits of 0.2 and 20 ng(Sn) L(-1) were achieved with SPME sampling and liquid-liquid extraction, respectively. Six analyses were performed for determination of TBT in PACS-2 sediment Certified Reference Material using both standard additions and isotope dilution procedures. For the latter, a 117Sn-enriched TBT spike was used. A concentration of 0.88 +/- 0.03 microg g(-1) (RSD 3.4%) obtained using standard additions was in good agreement with the certified value of 0.98 +/- 0.13 microg g(-1) as tin. Concentrations found using isotope dilution were 0.895 +/- 0.015 microg g(-1) (RSD 1.73%) as tin and 0.874 +/- 0.014 microg g(-1) (RSD 1.66%) as tin using a liquid-liquid extraction and SPME sampling, respectively. A 2-fold improvement in the precision of TBT concentration measurement using isotope dilution was clearly achieved, demonstrating its superiority in providing more accurate and precise results as compared to the method of standard additions. The isotope dilution technique eliminated the problem of poor reproducibility, which typically plagues SPME.

Determination of methylmercury and butyltin compounds in marine biota and sediments using microwave-assisted acid extraction, solid-phase microextraction, and gas chromatography with microwave-induced plasma atomic emission spectrometric detection.

A method is described for the determination of methylmercury and butyltin compounds in marine sediment and tissue using microwave-assisted acid extraction or digestion and solid-phase microextraction (SPME) followed by analysis using gas chromatography with microwave-induced plasma atomic emission spectrometric detection (GC-MIP-AES). Using the SPME-GC-MIP-AES method, enrichment factors for methylmercury and butyltin compounds of 50-100 were achieved, as compared to the typical hexane extraction, and measurements in marine tissue and sediment matrixes were possible at 1-2 microg/kg (methylmercury) and 10-100 ng/kg (butyltins). The SPME-GC-MIP-AES method was validated using several marine sediment and tissue matrix certified reference materials (CRMs) with certified values for methylmercury and butyltin compounds. The SPME-GC-MIP-AES method was used to measure methylmercury in four marine tissue CRMs ranging from oyster tissue at 13.0 +/- 1.0 microg/kg to fish tissue at 397 +/- 13 microg/kg (as Hg dry mass). Results from the SPME-GC-MIP-AES method were used in conjunction with results from other techniques to assign certified values for methylmercury in oyster, mussel, and fish tissue CRMs. Mono-, di-, and tributyltin were measured in three sediment CRMs at concentration levels of (0.08 +/- 0.03)-(0.35 +/- 0.05) mg/kg (as Sn dry mass).

Determination of rare and rare earth elements in soils and sediments by ICP-MS using Ti(OH)4–Fe(OH)3co-precipitation preconcentration

A method was developed for the determination of trace and ultratrace amounts of REE, Cd, In, Tl, Th, Nb, Ta, Zr and Hf in soils and sediments. With NaOH–Na2O2 as the flux, Ti(OH)4–Fe(OH)3 co-precipitation as the preconcentration technique and inductively coupled plasma mass spectrometry (ICP-MS) for measurement, the whole procedure was concise and suitable for batch analysis of multi-element solutions. An investigation was carried out of the Ti(OH)4–Fe(OH)3 co-precipitation system, and the results obtained showed that the natural situation of Ti tightly coexisting with Nb, Ta, Zr and Hf in geological samples plays a very important role in the complete co-precipitation of the four elements. The accuracy of this procedure was established using six Chinese soil and sediment certified reference materials (GSS and GSD), and the relative errors between the found and certified values were mostly below 10%.

Gas phase detection of tributyltin chloride arising from aqueous and solid matrices

The vapour phase above water spiked with tributyltin chloride (TBTCl) and PACS-2 sediment certified reference material was sampled with a solid phase microextraction fiber. The collected volatile compounds were analysed by GC-MS using a HBr–methanol-treated capillary column. Two ion sources were used for this study and their performance characteristics compared. These were electron impact (EI) and negative chemical ionisation (NCI), which allowed both detection of trace amounts of analytes (NCI source) and their identification. This approach provides structural information on the sampled species; at this stage no quantitation was attempted. TBTCl can be detected in the vapour phase above saline water or PACS 2 sediment after one night of passive sampling without any stirring or heating of the sample. This work indicates the need to consider evaporation of TBT as the chloride as a mechanism of loss of this analyte from water or sediment. This may take place from natural settings and contributes to the global biogeochemical cycle of tin; hydride or methyl forms of trace metals are not the only compounds capable of volatilising into the atmosphere.

Simple methodology for methylmercury and inorganic mercury determinations by high-performance liquid chromatography–cold vapour atomic fluorescence spectrometry

An analytical methodology was developed to separate and quantify methylmercury (MeHg) and inorganic mercury by high-performance liquid chromatography (HPLC)–cold vapour atomic fluorescence spectrometry (CV-AFS). The use of UV oxidation of the organic forms of mercury, the tin(II) chloride reduction in acidic medium of mercury and the introduction of a water vapour trap based on H 2SO 4/CaCl 2 resulted in a low detection limit (DL) (10±2 pg, mean value±S.D.). The apparatus was operationally optimised through the modified simplex method leading to an increase of the signal by a factor of 2. The method performance has been tested by determining the MeHg concentration in a sediment certified reference material (CRM) and the results were statistically indistinguishable from the certificate value ( α=0.05) both for the mean value and S.D.

Microwave-assisted extraction for methylmercury determination in sediments by high performance liquid chromatography-cold vapour-atomic fluorescence spectrometry

A simple and rapid procedure for methylmercury extraction from sediments based on microwave-assisted alkaline digestion with methanolic potassium hydroxide was optimized on parameters such as microwave power, extraction time and sample size. Organomercury species were extracted with dichloromethane in hydrochloric acid medium and back-extracted into ultra-pure water. The sediment extracts were injected into an analytical system composed of high-performance liquid chromatography-ultraviolet-post-column oxidation-cold vapour-atomic fluorescence spectrometry (HPLC-UV-PCO-CV-AFS) for methylmercury determination. Quantitative methylmercury recoveries were obtained when 0.15 g of sediment were suspended into 6 ml of 25% m/v methanolic potassium hydroxide and the slurry was exposed to microwave irradiation at 84 W for 2 min. The detection limit of proposed method was 12 ng g−1 while the relative standard deviation was less than 5%. The method was validated by the analysis of two sediment certified reference materials and the methylmercury concentrations found were in good agreement (95% confidence level) with the certified values.

Efficiency of solvent extraction methods for the determination of methyl mercury in forest soils.

Methyl mercury was determined by gas chromatography, microwave induced plasma, atomic emission spectrometry (GC-MIP-AES) using two different methods. One was based on extraction of mercury species into toluene, pre-concentration by evaporation and butylation of methyl mercury with a Grignard reagent followed by determination. With the other, methyl mercury was extracted into dichloromethane and back extracted into water followed by in situ ethylation, collection of ethylated mercury species on Tenax and determination. The accuracy of the entire procedure based on butylation was validated for the individual steps involved in the method. Methyl mercury added to various types of soil samples showed an overall average recovery of 87.5%. Reduced recovery was only caused by losses of methyl mercury during extraction into toluene and during pre-concentration by evaporation. The extraction of methyl mercury added to the soil was therefore quantitative. Since it is not possible to directly determine the extraction efficiency of incipient methyl mercury, the extraction efficiency of total mercury with an acidified solution containing CuSO4 and KBr was compared with high-pressure microwave acid digestion. The solvent extraction efficiency was 93%. For the IAEA 356 sediment certified reference material, mercury was less efficiently extracted and determined methyl mercury concentrations were below the certified value. Incomplete extraction could be explained by the presence of a large part of inorganic sulfides, as determined by x-ray absorption near-edge structure spectroscopy (XANES). Analyses of sediment reference material CRM 580 gave results in agreement with the certified value. The butylation method gave a detection limit for methyl mercury of 0.1 ng g(-1), calculated as three times the standard deviation for repeated analysis of soil samples. Lower values were obtained with the ethylation method. The precision, expressed as RSD for concentrations 20 times above the detection limit, was typically 5%.

Investigating the potential of high-performance liquid chromatography with atmospheric pressure chemical ionization-mass spectrometry as an alternative method for the speciation analysis of organotin compounds

Liquid chromatography with atmospheric pressure chemical ionization-mass spectrometry (LC-APCI-MS) was applied for the determination of butyl- and phenyltin compounds. Chromatography was performed on a 30 x 2 mm, 3 microm C18 column, enabling the separation of mono-, di- and trisubstituted butyl- and phenyltin compounds in less than 10 min using a water/1% trifluoroacetic acid/methanol gradient. While satisfactory retention and resolution is achieved for the di- and trisubstituted butyl- and phenyltin compounds, monobutyltin and monophenyltin cannot be resolved chromatographically. Depending on the parameter values of the interface, APCI-MS detection allows both specific detection of the molecular ion or cluster ion at low to intermediate fragmentor voltages or quasi-element specific detection of the Sn+ ion released from the organotin compounds at high fragmentor voltages. The sensitivity of MS detection is similar for butyl- and phenyltin compounds, but varies largely from mono- to trisubstituted organotin compounds with tributyl- and triphenyltin being the most sensitively detectable compounds. Detection limits are in the 20-65 pg (abs.) range in SIM mode and in the 750-2000 pg (abs.) range in the scan mode for tributyl- and triphenyltin and for dibutyl- and diphenyltin, respectively. Monobutyl- and monophenyltin can be detected with much lower sensitivity which, together with their unfavorable chromatographic behavior, accounts for the fact that they cannot be analyzed at environmentally relevant concentrations. Although LC-APCI-MS is generally less sensitive than comparable GC methods, it is applicable to the analysis of environmental samples as demonstrated by the analysis of the PACS-2 sediment certified reference material. Although the derivatization of the ionic organotin compounds, which particularly in real samples is a potential source of error, is circumvented when LC-APCI-MS is used, the extraction step is still critical and may lead to underestimation when quantitation is not done by the method of standard addition.

A quantitative extraction method for the determination of trace amounts of both butyl- and phenyltin compounds in sediments by gas chromatography-inductively coupled plasma mass spectrometry

A simple and reliable extraction method was developed for quantitative determination of both butyl- and phenyltin compounds in sediments by capillary gas chromatography combined with inductively coupled plasma mass spectrometry (GC-ICP-MS). Both types of organotin compounds were extracted quantitatively from sediment by mechanical shaking into tropolone-toluene and HCl-methanol. After phase separation and pH adjustment, these organotins were ethylated with sodium tetraethylborate. The method was evaluated by analyzing PACS-2 and NIES No. 12 sediment certified reference materials. The dibutyltin (DBT; 1.14 +/- 0.02 micrograms g-1) and tributyltin (TBT; 1.01 +/- 0.04 micrograms g-1) values observed in PACS-2 sediment closely matched the certified values (DBT, 1.09 +/- 0.15; TBT, 0.98 +/- 0.13 microgram g-1 as tin). The monobutyltin (MBT) value was higher (0.62 +/- 0.02 microgram g-1) by more than two fold over the reference value (0.3 microgram g-1 as tin). The concentrations of TBT (0.18 +/- 0.04 microgram g-1) and triphenyltin (TPhT; 0.0099 +/- 0.002 microgram g-1) in the NIES No. 12 sediment were also in good agreement with the certified and reference values of TBT (0.19 +/- 0.03 microgram g-1 as compound) and TPhT (0.008 microgram g-1 as compound), respectively. Recoveries of TBT, tripentyltin (TPeT) and TPhT from spiked sediments were satisfactory (TBT, 102 +/- 3.4%; TPrT, 96 +/- 3.4%; TPhT, 99 +/- 8.5%). The detection limits as tin were in the range 0.23-0.48 ng g-1 for a 0.5 g sample size. It is also noteworthy that clean-up of the extract is not necessary because of the superior selectivity of ICP-MS detection. The present method was successfully applied to marine sediment samples.

Hydride generation-electrostatic deposition-graphite furnace atomic absorption spectrometric determination of arsenic, selenium and antimony

A system is described and evaluated for the in situ collection of generated hydrides of As, Se and Sb in a graphite furnace using a high voltage electrostatic field. Analytical figures of merit are derived using graphite furnace atomic absorption detection and a characterization of the electrostatic deposition (ED) process is presented based on optimization studies. Absolute detection limits (LOD) of 30, 16 and 33 pg were obtained for As, Se and Sb, respectively, reflecting overall generation/collection efficiencies of 80±5, 71±3 and 62±6%, respectively. Precision of replicate determination was typically 4% R.S.D. at a concentration 40-fold above the LOD for a 1 ml sample volume. The accuracy of the approach was demonstrated through the analysis of coastal seawater and marine sediment certified reference materials.

Determination of Multielements in a NIES Candidate River Sediment Certified Reference Material by Instrumental Neutron Activation Analysis.

Determination of Multielements in a NIES Candidate River Sediment Certified Reference Material by Instrumental Neutron Activation Analysis.

Marine Sediment Certified Reference Material for Tin Speciation

A certified reference material for organotin analysis (NIES CRM No. 12 Marine Sediment) was prepared at National Institute for Environmental Studies. The starting material was a surface sediment sampled at the center of Tokyo Bay in 1989. The chemical and physical properties of the material indicated homogeneity of this CRM at practical level. Certified values are given for tributhyltin (0.19±0.03 mg TBT/kg dry wt.) and total tin (10.7±1.4 mg/kg dry wt.) contents and a reference value for triphenyltin (0.008 mg TPT/kg dry wt.) based on the analytical results from collaborative analysis. The organotin levels in this CRM are higher than the current average level of, but within the range of, TBT and TPT found in marine sediment along the Japanese coast. This CRM will be of practical value in the quality assurance of organotin analysis in marine environmental monitoring programs.

Extraction procedures for the determination of heavy metals in contaminated soil and sediment

Extraction tests are commonly used to study the mobility of metals in soils and sediments by mimicking different environmental conditions or dramatic changes on them. The results obtained by determining the extractable elements are dependent on the extraction procedure applied. The paper summarises state of the art extraction procedures used for heavy metal determination in contaminated soil and sediments. Two types of extraction are considered: single and sequential. Special attention is paid to the Standard, Measurement and Testing projects from the European Commission which focused on the harmonisation of the extraction procedures and on preparing soil and sediment certified reference materials for extractable heavy metal contents.

Analysis of Antarctic Marine Sediment by Inductively Coupled Plasma Atomic Emission and Total Reflection X-Ray Fluorescence Spectrometry

Microwave digestion and extraction techniques were developed for elemental analysis of Antarctic marine sediment by inductively coupled plasma atomic emission spectrometry (ICP-AES) and total reflection X-ray fluorescence (TXRF) spectrometry. These sample preparation techniques were tested by analyzing river sediment certified reference material (BCR-320). Concentrations of Al, Fe, Mn, Zn, Cr, Co, and Cu were determined by ICP-AES after microwave digestion of sediment in a mixture of HF + HNO3+ HCl + H3BO3with acceptable accuracy. Due to the strong matrix effect and spectral interference, Cd, Sn, Pb, Ni, and As cannot be determined using ICP-AES; however, the proposed microwave extraction procedure appears to be suitable for measurement of Zn, Cu, Pb, Ni, and As using TXRF spectrometry.

Study on stable coatings for determination of lead by flow-injection hydride generation and in situ concentration in graphite furnace atomic absorption spectrometry

Lead hydride was generated by flow-injection from 0.05 M oxalic acid sample solution by using 0.1 M HCl carrier solution and the reaction with 1.5% sodium borohydride in the presence of 2% potassium hexacyanoferrate(III) as a mild oxidizing agent. Pb was determined by in situ concentration in graphite furnace AAS. The hydride generation by flow-injection and trapping in the graphite tube coated with a highly stable trapping reagent (e.g. tungsten) allows automatic Pb determination. In a systematic investigation, the in situ concentration of Pb was studied in the temperature range 50–600° on graphite tubes coated with noble metals (Ir, Ir/Mg, Pd/Ir), and with W or Zr. The highest response was found on the Ir coatings at trapping temperatures of 200–300°, followed by the W and Zr coatings. The radiotracer 210Pb was used to measure hydride generation (95%) and trapping efficiency (71%) on a W-coated tube. Signal stability and reproducibility was tested over 400 trapping and atomization cycles, and the better performance was found with the W and Zr coatings at a precision of 3%. Trapping temperatures above 450°C can lead to errors in absorbance values owing to an adsorptive “carry-over” effect. A characteristic mass of about 21 pg Pb for W-coated tube (283.3 nm) and a detection limit (3σ) of about 0.25 ng was obtained with a 0.5 ml sample loop. The problem with Pb hydride generation is the relatively high reagent blank (1.3 ng in 30 s trapping time) even using chemicals of the highest purity. The method has been tested by applying it to the determination of Pb in a sediment certified reference material.

Comparison of methods to evaluate heavy metals in organic wastes

Abstract The conventional method for the digestion of residues using a mixture of nitric and perchloric acids was compared with the microwave procedure using both aqua regia and nitric acid as extractants, in order to determine which method fits better the routine measurements using inductively coupled plasma emission spectrometry (ICP‐AES). Urban domestic wastes, swine and dairy manure and NIES pond sediment certified reference material were used as samples. The microwave digestions were performed on sealed vessels by taking 500 mg of each residue and aqua regia (16 mL) or concentrated nitric acid (10 mL). The conventional nitric‐perchloric digestion was performed by heating 500 mg of each sample with 6 mL of HNO3 ‐HClO4 5+1 v/v in Pyrex digestion tubes until complete digestion. All extracts were analysed for Fe, Mn, Zn, Cu, Pb, Ni, Cr and Cd by ICP‐AES. Microwave extraction with aqua regia extracted higher amounts of metals from the certified pond sediment reference material than the USEPA‐SW 846‐method...

Determination of trace amounts of phosphorus in silicate materials by simultaneous inductively coupled plasma atomic emission spectrometry

Inductively coupled plasma atomic emission spectrometry (ICP-AES) implemented on a simultaneous spectrometer was used for the determination of trace amounts of phosphorus in rocks, soils and sediments. Samples were decomposed by using a mixture of concentrated hydrofluoric, perchloric and nitric acid in Teflon beakers. Overlap of emissions from other elements present in the samples with the polychromator spectral line at 214.914 nm for phosphorus was studied. The corresponding inter-element coefficients for overlap correction were determined and the optimum position for background readings was established. The limit of determination achieved was 24 ppm referred to the solid sample. The proposed method was tested by applying it to the analysis of rock, soil and sediment certified reference materials, and determining its short-time precision and method precision, which turned out to be 0.24–0.68% and 1.70–4.16%(relative standard deviation), respectively.

Determination of total chromium in sediments by FAAS

The determination of chromium by flame atomic absorption spectroscopy (FAAS), e.g. as performed for environmental matrices, is still a controversial matter as can be concluded from a literature review. Most controversy is due to the measurement conditions or the effect of the interferences; other conditions such as digestion seem to be less critical. Consequently, this paper reports a systematic study of the instrumental settings for the two flame modes that are most widely used: air-acetylene and nitrous oxide-acetylene. In connection with the study of experimental conditions, possible interferences are investigated involving nineteen cations and some anions in different ratios Cr:interferent. Different releasers to overcome interferences are considered. The results are critically compared with current literature. For the operational conditions the quality parameters such as the linear range, detection limits, precision and accuracy are established. Although the nitrous oxide-acetylene flame is mostly recommended, this study reveals that a better choice can be the use of a fuel-rich air-acetylene flame with the addition of 1% 8-hydroxyquinoline (oxine) as protective agent. The method is applied to and validated by four sediment certified reference materials.

Flame sample introduction system for inductively coupled plasma atomic emission spectrometry

An oxygen–hydrogen flame sample introduction system for inductively coupled plasma (ICP) atomic emission spectrometry is discussed. Linking two dissimilar sources was found to be a non-trivial exercise. A total consumption burner oxyhydrogen flame–ICP tandem source was used for the analysis of slurries of marine sediment Certified Reference Materials with particle diameters of less than 2 µm. Significant memory effects were observed. Detection limits were 0.3 ppm for Cu, 1 ppm for Mn and 1 ppm for Zn and the precision ranged between 1% and 3%(both determined using aqueous standards).