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Liver plays a major role in metabolism and acts as a source of energy for the body by storing glycogen. With the growing interest and investigation in the biological effects in recent years, it is important and necessary to develop accurate and comparable analytical methods for elements in bio-samples. It has, however, been 10 years since the tissue sample (bovine liver) of CCQM-K49 key comparison. The purpose of CCQM-K145 is to ensure the comparable and traceable measurement results for essential and toxic elements such as P, S, Zn, Mn, Ni, Mo, Sr, Cr, Co, Pb, As and Hg in bovine liver among NMIs and other designated measurement bodies worldwide. The comparison was agreed by IAWG as 6th IAWG Benchmarking Exercise with Zn and Ni as exemplary elements at the meeting in Korea in the early October 2016. The results of CCQM-K145 are expected to cover the measurement capability and support CMCs claiming for inorganic elements in the similar biological tissue materials and food samples. 30 NMIs and DIs registered in CCQM-K145. With respect to the methodology, a variety of techniques such as IDMS, ICP-OES, ICP-MS(non-ID), AAS and NAA were adopted by the participants. For Zn, Ni, Sr, Pb and Hg measurements, most participants chose ID-ICP-MS method, which showed the better performance in terms of consistency and reliability of the measurement results. In aspect of the traceability for the measurement results in CCQM-K145, most participants used their own (in house) CRMs or other NMI's CRMs to guarantee trace to SI unit. Most participants used similar matrix CRMs for quality control or method validation. Base on different statistic way to calculate the reference mass fraction values and associated uncertainties for each measurand, removal of the suspected extreme values, and discussion at the IAWG meetings, the median values are proposed as the KCRV for Zn, Ni, Mn, Mo, Cr, Pb and Hg; the arithmetic mean values are proposed as the KCRV for P, S, Sr, Co and As. In general, the performances of the majority of CCQM-K145 participants are very good, illustrating their measurement capabilities for Zn, Ni, P, S, Mn, Mo, Sr, Cr, As, Co, Pb and Hg in a complex biological tissue matrix. Bovine liver contains many kinds of nutrients and microelements, it can be regarded as a typical representative material of biological tissue and food. In CCQM-K145, the analytes involved alkali metals and transition elements, metalloids / semi-metals and non metals with a range of mass fraction from mg/g to μg/kg. CCQM-K145 also tested the ability of NMIs/DIs to determine elements that were easy to be lost and polluted, and interfered significantly. The chemical pretreatment methods of samples used in the comparison is suitable for general food and biological matrix samples. A variety of measurement methods used in the comparison represent the main instrumental technology for elemental analysis. Therefore, for supporting CMC claim, CCQM-K145 is readily applicable to measurement of more elements in a wide range of biological materials (including liquids and solids) and meat products. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Species-specific Hg isotope ratio data has increasingly become an important tool in understanding biogeochemistry of mercury. Among the plethora of analytical techniques capable of separating Hg species to date only gas chromatography has been used to study natural variations in their isotopic composition. Here, we report new methodology for precise and accurate Hg isotope ratio measurements of methylmercury in fish tissues at environmentally relevant levels using high performance liquid chromatography (HPLC) and cold vapour generation multi-collector inductively coupled plasma mass spectrometry (CVG MC-ICPMS). The chromatographic baseline separation of Hg species such as methylmercury (CH3Hg) and inorganic Hg (iHg) was achieved in isocratic mode using reverse phase HPLC with a mobile phase containing L-cysteine as a complexing agent and without the need for species derivatisation. The signal-to-noise ratio of Hg detection by MC-ICP-MS was improved using a cold vapour generation interface with SnCl2 as reducing agent. Challenges driven by the non-reactivity of CH3Hg with SnCl2 and, interferences caused by the presence of L-cysteine in the mobile phase were efficiently overcome through complete oxidation of isolated Hg species prior to cold vapour generation and species-specific Hg isotope ratio measurements. Combined standard uncertainties of δ199/198Hg, δ200/198Hg, δ201/198Hg and δ202/198Hg values determined from replicated measurements of CH3Hg in fish tissue reference materials BCR 463 and NIST SRM 1947 ranged from 0.10‰ to 0.22‰. The obtained δ-values for the Hg isotope ratios are in very good agreement with indicative values of NIST SRM 1947 and those previously reported for BCR 463 material. The developed technique offers a complimentary measurement method to gas chromatography MC-ICPMS in producing isotopically certified species-specific reference materials for Hg. Furthermore, evidence for Hg isotope fractionation induced by dissociation of CH3Hg and interactions with sulphur compounds in solution is provided here as well.

Speciation data for chromium in tobacco products, as obtained by complementary HPLC-ICP-MS and synchrotron-based X-ray Absorption Near-Edge Structure spectroscopy (XANES), are presented for the first time. Non-denaturing extraction conditions were investigated to avoid Cr species redox inter-conversion before analysis of extracts using HPLC-ICP-MS. Methodology based on HPLC-ICP-MS, which is compatible with the extraction conditions, was developed for separation and detection of inorganic Cr species such as Cr(III) and Cr(VI) in aqueous standard solutions. The instrumental limits of detection (3σ criterion) obtained for Cr(III) and Cr(VI) were 0.12 and 0.08 ng g−1 Cr, respectively. The total Cr extracted from 3R4F cut tobacco with water was around 10% of the total Cr in the solid (1949 ± 171 ng g−1 of Cr on a dry weight basis), with 75% of the aqueous Cr associated with species of molecular mass > 3 kDa. Cr(III) was the main identified species in the tobacco extracts using HPLC-ICP-MS, whilst Cr(VI) could not be detected. In situ XANES analysis revealed that the cut tobacco from 3R4F reference cigarettes contained only Cr(III). Following leaching with water, leaching with sodium dodecylsulfate (SDS) on the solid residue led to extraction of a further 10% of the Cr contained in the solid tobacco. The total Cr data obtained by ICP-MS for HNO3 and HNO3/HF acid digests of 3R4F cut tobacco suggested that additional 12% of the total Cr in the solid appears to be associated with silicates, which are known to occur naturally in tobacco products. Although Cr species could not be detected in water leachates from 3R4F smoke condensates using the HPLC-ICP-MS method developed here, XANES measurements identified Cr(III) as the main Cr species present in cigarette smoke condensate, with no detectable Cr(VI). HPLC-ICP-MS data obtained for smoke condensates from cigarettes spiked with Cr(III) before smoke collection revealed that Cr(III) is the main Cr species in present the water soluble fraction of the condensate. Spiking experiments demonstrated that Cr(VI) was highly unstable in trapped smoke condensate. In this work no evidence was observed for the presence of Cr(VI) in mainstream smoke generated from 3R4F cigarettes.

CCQM-K125 was organized by the Inorganic Analysis Working Group (IAWG) of CCQM to assess and document the capabilities of the national metrology institutes (NMIs) or the designated institutes (DIs) to measure the mass fractions of trace elements (K, Cu and I) in infant formula. Government Laboratory, Hong Kong SAR (GLHK) acted as the coordinating laboratory. In CCQM-K125, 25 institutes submitted the results for potassium, 24 institutes submitted the results for copper and 8 institutes submitted the results for iodine. For examination of potassium and copper, most of the participants used microwave-assisted acid digestion methods for sample dissolution. A variety of instrumental techniques including inductively coupled plasma mass spectrometry (ICP-MS), isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS), inductively coupled plasma optical emission spectrometry (ICP-OES), atomic absorption spectrometry (AAS), flame atomic emission spectrometry (FAES) and microwave plasma atomic emission spectroscopy (MP-AES) were employed by the participants for determination. For analysis of iodine, most of the participants used alkaline extraction methods for sample preparation. ICP-MS and ID-ICP-MS were used by the participants for the determination. Generally, the participants' results of CCQM-K125 were found consistent for all measurands according to their equivalence statements. Except with some extreme values, most of the participants obtained the values of di /U(di ) within ± 1 for the measurands. Main text To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Polybrominated diphenylethers (PBDE), used as flame retardants, are named as priority substances in the Directive 2000/60/EC of the European parliament and of the council establishing a framework for Community action in the field of water policy. An annual average environmental quality standard (EQS) for inland surface waters of 0.0005 mu g/L (0.0002 mu g/L for other surface waters) for PBDE congeners involved in the technical penta-PBDE mixtures containing PBDE with five bromine atoms has been established. The directives focus especially on the congeners PBDE 28, 47, 99, 100, 153 and 154 contained in the penta-PBDE mixture. Up to now, no reference measurement procedures have been established reaching the limits of quantification (LOQs) and the associated uncertainties as defined in the directives with results traceable to the SI. Within a recent European project on metrology, different approaches for the traceable quantification of PBDE, based on liquid/liquid or solid phase extraction followed by the detection with gas chromatography coupled to either inductively coupled plasma mass spectrometry or triple quadrupole mass spectrometry, were investigated and the related LOQs and expanded uncertainties of the results were compared. A complete uncertainty budget for each method was estimated according to the Guide to the Expression of Uncertainty in Measurement (GUM). All presented analytical procedures can serve as reference measurement procedures regarding the LOQs and their associated expanded uncertainties for monitoring the six priority PBDEs named above. LOQs as low as 0.026 ng/kg with an associated expanded uncertainty of 0.002 ng/kg could be achieved (C) 2016 The Authors. Published by Elsevier B.V.

The accurate determination of alcohol content and original gravity of beer is crucial to investigations of adulteration and substitution. Unfortunately, beer samples are unstable with respect to compositional change by evaporation and biological degradation. Recent guidelines recommend freezing suspect samples to preserve them. This technique was compared with other preservation techniques. Samples of live cask beer and pasteurised beer were stored at 4 °C, at 4 °C with the addition of salicylic acid, and frozen at −18 °C. They were analysed at intervals for their alcohol content and original gravity. It was found that the sample’s analytical integrity was maintained for 18 months by degassing and freezing in glass bottles.

High accuracy procedures for the determination of arsenic are needed for assigning reference values to certified reference materials (CRMs). There are a number of problems associated with the determination of total arsenic by inductively coupled plasma–mass spectrometry. Arsenobetaine (AsB) (the major species in fish) gives an enhanced response (9%) when compared to inorganic arsenic(V) and is very difficult to decompose. Chloride causes interference at m / z 75 by the formation of ArCl + and chloride levels can be significant in marine fish. Also residual carbon in digests can lead to enhancement of arsenic signals by charge transfer effects. This can easily lead to erroneous quantification when compared to standards that do not contain carbon. This newly developed procedure overcomes these issues by complete mineralisation of the matrix leaving insignificant amounts of residual carbon and by removal of chlorine by evaporation. A detection limit of 30 ng/g was achieved. Recoveries for the following CRMs: DORM 2 100.1 ± 4.3%, SRM1548 96.1 ± 4.6%, BCR 422 103.6 ± 6.2% and SRM2976 105.9 ± 6.2% were obtained. The digestion procedure uses open vessel wet digestion with a mixture of sulfuric and nitric acid held at 300 °C. The decomposition of AsB was confirmed by speciation analysis of the digest. Carbon ( m / z 13) was monitored to demonstrate the efficiency of the digestion. Instrumentation for the reduction of ArCl + interference was not required and this view is supported by the recovery data. Measurements were performed by external calibration using tellurium as an internal standard.

Size-exclusion, anion-exchange and reversed-phase ion-pair (RP-IP) HPLC were used in combination with ICP-(Q)MS for selenium (Se)-specific detection and quantitation of Se-compounds in extracts of Se-yeast and Se-methylselenocysteine (SeMC) based supplements. On-line electrospray ionisation (ESI)-MS/MS combined with RP-IP HPLC allowed characterisation of such materials in terms of species identification. Accelerated solvent extraction (ASE) was evaluated for extraction of the Se-compounds from the complex matrices in water. Alternatively, digestion with proteolytic enzymes was used for yeast protein hydrolysis. The use of ultrasonic nebulisation in combination with HPLC-ICP-(Q)MS for Se speciation led to detection limits up to six-fold lower (as low as ng l−1 levels) than those obtained with pneumatic nebulisation. Such enhancement of the ICP-MS capabilities for Se detection, combined with an improved separation using the newly developed RP-IP-HPLC method, allowed quantification of minor Se species such as SeMC in yeast extracts. Identification of the main compounds in yeast and SeleniumMC™ tablet hydrolysates as SeMet and SeMC, respectively, was accomplished by on-line RP-IP HPLC with ESI-MS/MS. Identification of SeMC in yeast digests, on the basis of retention time, molecular mass determination for the [M + H]+ 80Se ions (m/z 184) and detection of its product ions, is reported here for the first time. The mass spectral confirmation for SeMC in yeast is of interest, as this species is believed to be metabolised in animals and humans to methylselenol (CH3SeH), an anti-carcinogenic Se-metabolite.

The determination of total deoxyribonucleic acid (DNA) concentration is of great importance in many biological and bio-medical analyses. The quantification of DNA is traditionally performed by UV spectroscopy; however the results can be affected greatly by the sample matrix. The proposed method quantifies phosphorus in digested calf thymus DNA and human DNA by high performance liquid chromatography (HPLC) combined with inductively coupled plasma mass spectrometry (ICP-MS). The method presented showed excellent baseline separation between all four DNA mono-nucleotides and 5'UMP. The ability of LC-ICP-MS to provide an internal check that only DNA derived phosphorus was counted in the assay was demonstrated by establishing a mass balance between the total phosphorous signal from undigested DNA and that from the speciated DNA. Column recoveries ranging from 95% to 99% for phosphorus resulted in a mass balance of 95% ± 0.5% for standard nucleotides, determined by LC-ICP-MS, compared to total DNA determined by flow injection coupled to ICP-MS (FI-ICP-MS). The method for quantification was validated by analysis of NIST SRM 2,372; a total speciated DNA recovery of 52.1 ng/μL, compared with an expected value of 53.6 ng/μL, was determined by external calibration. From repeat measurements, a mass balance of 97% ± 0.5% for NIST DNA was achieved. The method limits of detection for individual nucleotides were determined between 0.8 and 1.7 μg L(-1) ((31)P) for individual nucleotides by LC-ICP-MS, and 360 ng L(-1) for 5'AMP by direct nebulisation.

cited By 12; International audience; Six metrology institutes (NMIs) representing at the Comité International des Poids et Mesures (CIPM) 4 Member States of the Metre Convention and 2 international organisations, and 8 "expert" laboratories selected outside CIPM have compared their capabilities to quantitatively measure methylmercury (MeHg) in a prepared tuna material containing approximately 4.3 mg kg-1 Hg. This comparison was the object of the CIPM-Comité Consultatif pour la Quantité de Matière (CCQM) Pilot Study 39, organised by the Institute for Reference Materials and Measurements (IRMM), from the European Commission - Joint Research Centre. Beside the test material itself, a bottle of the BCR-464 tuna Certified Reference Material (CRM) and an ampoule of IRMM-670, a 202Hg isotope enriched MeHg candidate isotopic CRM, were distributed to all participants, who were free to apply the measurement strategy of their choice. Four, including 1 NMI, relied on external calibration or the method of standard additions, whereas the other 10 implemented an isotope dilution mass spectrometry (IDMS) approach and chose to use the IRMM-670 for their measurements. Alkaline digestion at room temperature (with manual shaking) or high temperature (under sonication, oven or hot plate conditions) was employed by most participants, with hydrochloric acid leaching the second most popular choice. Alkylation (4 phenylations, 4 ethylations and 3 propylations) in the aqueous phase was preferred by a large majority over butylation by the Grignard reaction. All participants were requested to estimate the uncertainty associated with their results and 9 out of 14 stated relative combined uncertainties below 6% (k = 2). Despite this apparent consensus, the perception of which factor caused the largest contribution to this estimation differed among participants because of the differences in the analytical methodologies deployed but also because of wide differences of the concepts of uncertainty estimation. The 'mixture mode' (MM) median, calculated also from the measurement uncertainties stated by the participants, was 1.967 ± 0.204 × 10-5 mol kg -1 (95% confidence). Twelve of the results were re-grouped within a range of less than 0.3 × 10-5 mol kg-1 (MM median = 1.967 ± 0.162 × 10-5 mol kg-1, 95% confidence): they nearly all (1 exception) overlapped with each other within k = 2 stated uncertainties. For the other 2 results the uncertainty seemed to have been particularly underestimated as they lay, respectively, at more than 20% above and less than -40% below the overall average. The relative standard deviation of the results of 9 laboratories out of the 10 that applied IDMS was about 2.6%. It can be assumed from the degree of equivalence shown by 12 out of 14 study participants that, at present, laboratories worldwide are potentially able to supply accurate results for MeHg in fish-type matrices (containing about 2 × 10-5 mol kg-1) within ± 10% uncertainty. This encouraging outcome permitted scheduling of a follow-up CCQM-K43 key comparison for a lower MeHg content level in salmon tissues. © The Royal Society of Chemistry 2005.

The key comparison CCQM-K89 was undertaken to demonstrate the capability of participating NMIs and DIs in measuring the contents of incurred trace elements (total arsenic, cadmium and lead) and essential elements (calcium and zinc) at ?g/g (for arsenic, cadmium, lead and zinc) and mg/g (for calcium) levels in a herb matrix sample by various analytical techniques. This key comparison was organized by the Government Laboratory of the Hong Kong Special Administrative Region (GLHK) and agreed at the Inorganic Analysis Working Group Meeting in Hind?s, Sweden in October 2010 as a benchmarking exercise with arsenic (a trace element) and calcium (an essential element) chosen as the 'exemplary' elements. It was also agreed that a pilot study CCQM-P126 would be run in parallel with this key comparison. The key comparison serves to facilitate claims by participants on the Calibration and Measurement Capabilities (CMCs) as listed in Appendix C of the Key Comparison Database (KCDB) under the Mutual Recognition Arrangement of the International Committee for Weights and Measures (CIPM MRA). A total of 20 NMIs/DIs registered for this programme and 18 of them submitted their results. Most of the participants used microwave acid digestion methods for sample dissolution. For the instrumental determination, a variety of techniques like ICP-MS, AAS, INAA, ICP-AES were employed by the participants. For this key comparison, inorganic core capabilities have been demonstrated by concerned participants with respect to methods including ICP-MS (without isotope dilution), ID-ICP-MS, ICP-AES, INAA, AAS and ion chromatography with iteratively matrix-matched calibration on the determination of total arsenic, calcium, cadmium, lead and zinc in a matrix of herb. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

The greater Manchester Consortium for Advanced Continuing Education and Training (CONTACT) – a partnership of Manchester and Salford Universities, Manchester Polytechnic, UMIST and Manchester Business School – has recently introduced a novel Continuing Professional Development (CPD) Award scheme which aims to help in meeting the national need for the continuous updating of the knowledge and skills of individuals in industry, commerce and the public sector. The scheme is based on the wide range of post-experience short courses offered by these five institutions. The Award is obtained by accumulating credit from a series of courses attended at any of the five. The Award certificate is given when 120 contact hours have been successfully completed and lists the courses accredited.