Assay in serum of exchangeable copper and total copper using inductively coupled plasma mass spectrometry (ICP-MS): development, optimisation and evaluation of a routine procedure.
Scand J Clin Lab Invest
; 80(8): 630-639, 2020 Dec.
Article
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| MEDLINE
| ID: mdl-32955383
ABSTRACT
The assay in serum of non-caeruloplasmin copper, as exchangeable copper after complexation with EDTA (ExCu) and total copper has been evaluated and compared in patients with varying c-reactive protein(CRP). Measurement of ExCu and total copper, range 0.2-47.2 µmol/L, was developed using ICP-MS. The chelating agents EDTA and TEPA were compared over 0.0-10 g/L after incubation with serum for 60 mins followed by ultrafiltration with Amicon 10 kDa filter. The assay for ExCu was optimised with EDTA 3 g/L (8.1 mmol/L) maintained at pH 7.0-8.0 before ultrafiltration. TEPA was not as selective in chelation of copper. Patients n = 82 were studied in relation to changes in inflammatory marker CRP and a group of patients n = 37 with normal CRP. The ExCu assay gave excellent recoveries (94-102 % but poor recovery for free uncomplexed copper), good repeatability, limit of quantitation 0.19 µmol/l with a provisional reference range 0.48 to 1.63 µmol/L (n = 37 patients). The range for relative exchangeable copper (exchangeable copper divided by total serum copper) was 2.49 to 9.96 %. ExCu was elevated in conditions with increased CRP greater than 100 mg/L suggesting an effect of inflammation on the free copper fraction. A reliable and reproducible assay for ExCu and total copper has been developed. The upregulated inflammatory state increases the ExCu suggesting excess free copper.
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MEDLINE
Asunto principal:
Espectrofotometría Atómica
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Bioensayo
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Ácido Edético
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Cobre
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Degeneración Hepatolenticular
Idioma:
En
Revista:
Scand J Clin Lab Invest
Año:
2020
Tipo del documento:
Article