TY - JOUR

T1 - Redox speciation of iron, manganese, and copper in cerebrospinal fluid by strong cation exchange chromatography – sector field inductively coupled plasma mass spectrometry

AU - Solovyev, Nikolay

AU - Vinceti, Marco

AU - Grill, Peter

AU - Mandrioli, Jessica

AU - Michalke, Bernhard

N1 - Funding Information: The authors are grateful to the CSF sampling facility staff and all the patients, who provided the biological material. Dr. Nikolay Solovyev would like to thank the Russian Foundation for Basic Research (grant No. 16-33-60004 mol_a_dk) for funding the research stay at the Helmholtz Zentrum M?nchen. Dr. Marco Vinceti acknowledges the financial support from the Fondazione di Vignola, Italy. Funding Information: The authors are grateful to the CSF sampling facility staff and all the patients, who provided the biological material. Dr. Nikolay Solovyev would like to thank the Russian Foundation for Basic Research (grant No. 16-33-60004 mol_a_dk ) for funding the research stay at the Helmholtz Zentrum München. Dr. Marco Vinceti acknowledges the financial support from the Fondazione di Vignola, Italy. Publisher Copyright: © 2017 Elsevier B.V. Copyright: Copyright 2018 Elsevier B.V., All rights reserved.

PY - 2017/6/22

Y1 - 2017/6/22

N2 - A new method of simultaneous redox speciation of iron (II/III), manganese (II/III), and copper (I/II) in cerebrospinal fluid (CSF) has been designed. For the separation of redox species strong cation exchange chromatography (SCX) with isocratic elution was employed. Species were detected using inductively coupled plasma sector field mass spectrometry (ICP-sf-MS), operating at medium resolution. The following parameters were optimized: analytical column, eluent composition and pH, CSF injection volume and dilution factor. Analytical column Dionex IonPac CS5A RFIC 4*250 mm was found to retain and separate species of interest the most effectively under the isocratic elution with a buffer, containing 50 mM ammonium citrate, 7.0 mM pyridine-2,6-dicarboxylic acid at pH = 4.2 and flow rate of 0.8 L min−1. Injection volume of 50 μL with CSF sample dilution of 1/3 (v/v) with the eluent was shown to result in minimal matrix suppression. For species identification, retention time matching with standards was used. The stability of metalloproteins (ferritin, transferrin, and ceruloplasmin) under elution conditions was evaluated. For the quantification of redox species, external calibration was employed. To avoid column contamination, a blank was run after measurement and all quantification values were blank subtracted. For recovery checks, species quantification data was verified against total content of an element, measured by dynamic reaction cell ICP-MS. Recoveries (sum of quantified species vs. total element determinations) were 82.5 ± 22% (Mn), 92 ± 11% (Fe), and 88.7 ± 12% (Cu). The method was tested using 38 real CSF samples. Limits of detection (3σ) for the CSF samples were 0.5 μg L−1, 0.6 μg L−1, and 0.8 μg L−1 for Fe, Mn, and Cu species, respectively. Retention time precision was 1–7.5% (as RSD), whereas peak area RSDs were in the range 5–11%, both depending on the species.

AB - A new method of simultaneous redox speciation of iron (II/III), manganese (II/III), and copper (I/II) in cerebrospinal fluid (CSF) has been designed. For the separation of redox species strong cation exchange chromatography (SCX) with isocratic elution was employed. Species were detected using inductively coupled plasma sector field mass spectrometry (ICP-sf-MS), operating at medium resolution. The following parameters were optimized: analytical column, eluent composition and pH, CSF injection volume and dilution factor. Analytical column Dionex IonPac CS5A RFIC 4*250 mm was found to retain and separate species of interest the most effectively under the isocratic elution with a buffer, containing 50 mM ammonium citrate, 7.0 mM pyridine-2,6-dicarboxylic acid at pH = 4.2 and flow rate of 0.8 L min−1. Injection volume of 50 μL with CSF sample dilution of 1/3 (v/v) with the eluent was shown to result in minimal matrix suppression. For species identification, retention time matching with standards was used. The stability of metalloproteins (ferritin, transferrin, and ceruloplasmin) under elution conditions was evaluated. For the quantification of redox species, external calibration was employed. To avoid column contamination, a blank was run after measurement and all quantification values were blank subtracted. For recovery checks, species quantification data was verified against total content of an element, measured by dynamic reaction cell ICP-MS. Recoveries (sum of quantified species vs. total element determinations) were 82.5 ± 22% (Mn), 92 ± 11% (Fe), and 88.7 ± 12% (Cu). The method was tested using 38 real CSF samples. Limits of detection (3σ) for the CSF samples were 0.5 μg L−1, 0.6 μg L−1, and 0.8 μg L−1 for Fe, Mn, and Cu species, respectively. Retention time precision was 1–7.5% (as RSD), whereas peak area RSDs were in the range 5–11%, both depending on the species.

KW - Cerebrospinal fluid

KW - Speciation

KW - Iron

KW - Manganese

KW - Copper

KW - Cation exchange chromatography – inductively coupled plasma mass spectrometry

UR - http://www.scopus.com/inward/record.url?scp=85017421432&partnerID=8YFLogxK

U2 - 10.1016/j.aca.2017.03.040

DO - 10.1016/j.aca.2017.03.040

M3 - Article

C2 - 28502424

VL - 973

SP - 25

EP - 33

JO - Analytica Chimica Acta

JF - Analytica Chimica Acta

SN - 0003-2670

ER -