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).
The demonstration of competency and equivalence for the assessment of levels of contaminants and nutrients in primary foodstuffs is a priority within the 10-year strategy for the CCQM Organic Analysis WG series of Track A core comparisons. The area of low polarity analytes in high fat foods had not been covered by the OAWG for many years since the key comparison CCQM-K21 p,p'-DDT in fish oil occurring in 2000. Benzo[a]pyrene (BaP) is one of the markers for the occurrence of PAHs in foods, for which maximum residue limits are enforced in many countries. Edible oil and fats are the main source of human PAH intake. BaP may form in edible oils by pyrolytic processes, such as incomplete combustion of organic substances. Worldwide regulatory limits of BaP in edible fats and oils are from 2.0 μg/kg to 10 μg/kg. Comparable and traceable measurement results for BaP in oil are important worldwide. Thus BaP in edible oil was the model system selected to align within the OAWG strategy. 16 NMIs and DIs participated in CCQM-K146. Different methods such as liquid-liquid extraction, GPC and SPE were applied in the sample pre-treatment and HPLC-FLD, HPLC-MS/MS, and GC-MS or GC-MS/MS were applied for detection by the participants. Most participants either used their own CRMs, other NMI's CRMs or pure materials assessed in house to guarantee traceability to SI for the calibrants. One lab was excluded from the KCRV evaluation, as they did not meet the CIPM metrological traceability requirements for their calibrant. Regarding the data evaluation, five labs withdrew their results from the statistical evaluation of the KCRV for technical reasons. In line with the OAWG guidance document for KCRV estimator selection, the Hierarchical Bayes option was selected for the KCRV value, which was determined as 2.74 μg/kg with a standard uncertainty of 0.03 μg/kg. The remaining ten institutes that were included in the calculation of the consensus KCRV all agreed within their standard uncertainties. In general, the majority of CCQM-K146 participants performed very well. Therefore, this Track A Key Comparison directly illustrates the capabilities in determining mass fraction of organic compounds, with molecular mass of 100 g/mol to 500 g/mol, having low polarity pKow < -2, in mass fraction range from 0.1 μg/kg to 1000 μg/kg in a high fat, low protein, low carbohydrate food matrix. 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).
CCQM-K124 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 (As, B, Cd, Ca, Cr, Hg and Mo) and hexavalent chromium (Cr(VI)) in drinking water. The National Metrology Institute of Japan (NMIJ) and the Government Laboratory, Hong Kong SAR (GLHK) acted as the coordinating laboratories. This comparison is divided into two parts. Part A was organized by the NMIJ and the trace elements were the analytes, and Part B was organised by the GLHK and Cr(VI) was the analyte. In Part A, results were submitted by 14 NMIs and nine DIs. The participants used different measurement methods, though most of them used direct measurement using inductively coupled plasma-optical emission spectrometry (ICP-OES), inductively coupled plasma-mass spectrometry (ICP-MS), and isotope dilution technique with ICP-MS. The results of As, B, Cd, Ca and Cr show good agreement with the exception of some outliers. Concerning Hg, instability was observed when the sample was stored in the light. And some participants observed instability of Mo. Therefore, it was agreed to abandon the Hg and Mo analysis as this sample was not satisfactory for KC. In Part B, results were submitted by six NMIs and one DI. The methods applied were direct measurement using 1,5-diphenylcarbazide (DPC) derivatisation UV-visible spectrophotometry, standard addition using ion chromatography-UV-visible spectrophotometry or HPLC—inductively coupled plasma-mass spectrometry (ICP-MS) and isotope dilution technique with ion chromatography—ICP-MS. The results of all participants show good agreement. Accounting for relative expanded uncertainty, comparability of measurement results for each of As, B, Cd, Ca, Cr and Cr(VI) was successfully demonstrated by the participating NMIs or DIs. 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 CCQM-K78.a comparison was coordinated by the BIPM on behalf of the CCQM Organic Analysis Working Group for NMIs and DIs which provide measurement services in organic analysis under the CIPM MRA. The key comparison forms part of the OAWG 10-year strategic plan of comparisons. CCQM-K78.a underpins the demonstration of capabilities for value assignment of high polarity calibration solutions. The model system selected was amino acids in aqueous solution. Participants were required to assign the mass fractions, expressed in μg/g, of phenylalanine (Phe), leucine (Leu), isoleucine (Ile) and proline (Pro) present in solution in 0.01 N hydrochloric acid. The content and analytical challenges of the selected analytes are representative of those for typical calibration solutions for polar organic analytes in aqueous solution. Participation in CCQM-K78, a benchmarked measurement capability for assigning the mass fraction content of polar organic compounds (pKow > -2) present at a mass fraction range between 50 μg/g and 500 μg/g in an aqueous solution. It also tested capabilities for the quantitative assignment of isomeric polar compounds of similar chromatographic retention time properties. A satisfactory level of agreement of the results was obtained between participants and with gravimetric values for amino acid content. In the cases where the agreement was not satisfactory, the participants were able to identify a technical cause for the inconsistency. The comparison demonstrated the trueness and precision of double IDMS-based methods as a primary measurement procedure for the quantification of polar analytes in aqueous solution when an isotopically labelled version of the analyte is available as the internal standard. It also demonstrated that amino acid quantification using pre- or post-column derivatization with UV or FLD detection can provide results with comparable levels of performance. In this case, where the purity of the primary calibrators had been assigned with a relative standard uncertainty below 0.2%, results consistent with the KCRV within a relative expanded uncertainty in the range 1% - 2% could be realized and levels of 2%-4% were routinely achieved. KEY WORDS FOR SEARCH Amino acid quantification, leucine, isoleucine, proline, phenylalanine, calibration solution, standard solution, IDMS, primary measurement procedure, polar solution, peptide quantification 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).
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.