Patriarca M.,Istituto Superiore di Sanita |
Weykamp C.,MCA Laboratory |
Arnaud J.,Institut Universitaire de France |
Jones R.L.,National Center for Environmental Health |
And 3 more authors.
Journal of Analytical Atomic Spectrometry | Year: 2015
International standards for the recognition of the competence of testing laboratories require that measurement results should be traceable to a conventionally agreed reference. This should be achieved by appropriate calibration of equipment and method validation involving analysis of certified reference materials (CRM). However, these are costly and for many analytical procedures, few are available. Participation in external quality assessment schemes (EQAS) may provide a mean to support the laboratory traceability statement, if the values assigned to test samples are traceable to a stated reference. Values may be assigned to EQAS test samples by a variety of techniques but there has been no direct comparison of results obtained when these procedures are applied to the same samples. In this study, traceable values for Cu, Se and Zn concentrations were assigned to three batches of EQAS serum samples, by analysis by expert laboratories together with CRMs, and compared with those obtained by three other of the approaches described in ISO 13528; analysis by a definitive method (ID-ICP-MS); determination of robust consensus mean from the results of expert laboratories; robust consensus mean of results from EQAS participants. The assigned values (μmol L-1) ± expanded uncertainty (%) for the low, medium and high pools obtained by ID-ICP-MS were: Cu 13.37 ± 1.2, 21.03 ± 1.8, 28.73 ± 1.2; Se 0.74 ± 3.5, 1.51 ± 3.4, 3.11 ± 3.6; Zn 9.69 ± 4.9, 22.52 ± 1.5, 30.85 ± 3.8. Concentrations determined using the three other approaches were similar but the uncertainties increased as the methodologies became increasingly less rigorous. This journal is © The Royal Society of Chemistry.
Loeschner K.,Technical University of Denmark |
Harrington C.F.,Trace Element Center |
Kearney J.-L.,Trace Element Center |
Langton D.J.,University Hospital of North Tees |
Larsen E.H.,Technical University of Denmark
Analytical and Bioanalytical Chemistry | Year: 2015
Hip replacements are used to improve the quality of life of people with orthopaedic conditions, but the use of metal-on-metal (MoM) arthroplasty has led to poor outcomes for some patients. These problems are related to the generation of micro- to nanosized metal wear particles containing Cr, Co or other elements, but the current analytical methods used to investigate the processes involved do not provide sufficient information to understand the size or composition of the wear particles generated in vivo. In this qualitative feasibility study, asymmetric flow field-flow fractionation (AF4) coupled with inductively coupled plasma mass spectrometry (ICP-MS) was used to investigate metal protein binding and the size and composition of wear metal particles present in serum and hip aspirates from MoM hip replacement patients. A well-established HPLC anion exchange chromatography (AEC) separation system coupled to ICP-MS was used to confirm the metal-protein associations in the serum samples. Off-line single particle ICP-MS (spICP-MS) analysis was used to confirm the approximate size distribution indicated by AF4 of the wear particles in hip aspirates. In the serum samples, AF4-ICP-MS suggested that Cr was associated with transferrin (Tf) and Co with albumin (Alb) and an unidentified species; AEC-ICP-MS confirmed these associations and also indicated an association of Cr with Alb. In the hip aspirate sample, AF4-ICP-MS suggested that Cr was associated with Alb and Tf and that Co was associated with Alb and two unidentified compounds; AEC analysis confirmed the Cr results and the association of Co with Alb and a second compound. Enzymatic digestion of the hip aspirate sample, followed by separation using AF4 with detection by UV absorption (280 nm), multi-angle light scattering and ICP-MS, suggested that the sizes of the Cr-, Co- and Mo-containing wear particles in a hip aspirate sample were in the range 40-150 nm. Off-line spICP-MS was used to confirm these findings for the Co- and Cr-containing nanoparticles. Whilst limited in scope, the results are sufficient to show the interaction of ions with transport proteins and give an indication of particle size, providing useful pathological indices. As such, the methods indicate a new way forward for in vivo investigation of the processes which lead to tissue necrosis and hip loosening in patients with MoM hip replacements. © 2015 Springer-Verlag.
Harrington C.F.,Trace Element Center |
Taylor A.,Trace Element Center
Journal of Pharmaceutical and Biomedical Analysis | Year: 2015
Many pharmaceuticals contain metals, either as part of the active compound or within the formulation. They are also found in related products such as dietary supplements and toiletries. Concentrations of metals in biological fluids or tissues from patients taking these agents, are measured where there may be an adverse reaction, dose-related toxicity or for therapeutic drug monitoring. Other situations, for analysis of environmental samples include occupational exposure (manufacture, administration to patients, pharmaceutical research) or in investigations of poisoning. Highly sensitive and accurate analytical methods are now available to determine the total metal concentration in a specific sample, but also to measure the specific chemical form of the drug, a metabolite of the drug, or the drug's interaction with important cellular components, such as DNA. The use of ICP-MS to measure total metal concentrations, or HPLC coupled to ICP-MS for the more complex speciation measurements, will depend on the type of information that is required. For the investigation of the drug species present, other complementary analytical techniques such as electrospray mass spectrometry (LC-MS/MS) are required for a full structural elucidation of the analytes. In this current publication we highlight the measurement of two metal(loid) based pharmaceutical drugs for the treatment of cancer. One 4-(N-(S-glutathionylacetyl)amino) phenylarsenoxide (GSAO) containing arsenic and under investigation for the treatment of solid tumours, and the second cis-diamminedichloroplatinum (II) (cisplatin) containing platinum and widely used in the clinical setting as a front line treatment against various neplasias in particular testicular, ovarian, bladder and head and neck cancers. © 2014 Elsevier B.V.