Human Plasma Copper Proteins Speciation by Size Exclusion Chromatography Coupled to Inductively Coupled Plasma Mass Spectrometry. Solutions for Columns Calibration by Sulfur Detection

• Published in: Analytical chemistry (Washington) Vol. 82; no. 16; pp. 6904 - 6910
• Main Authors: Balkhi, Souleiman El, Poupon, Joël, Trocello, Jean-Marc, Massicot, France, Woimant, France, Laprévote, Olivier
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 15.08.2010
• Subjects: Analytical chemistry; Calibration; Carrier Proteins - blood; Ceruloplasmin - analysis; Chemistry; Chromatographic methods and physical methods associated with chromatography; Chromatography; Chromatography, Gel - methods; Chromatography, Gel - standards; Copper; Copper - blood; Exact sciences and technology; Humans; Mass spectrometry; Mass Spectrometry - methods; Metalloproteins - blood; Other chromatographic methods; Oxygen; Oxygen - chemistry; Plasma; Proteins; Serum Albumin - analysis; Speciation; Spectrometric and optical methods; Sulfur; Sulfur - analysis; Ultraviolet radiation; Human; Plasma; Oxygen; Coupled method; Use; Interference; Albumin; Calibration; Probe; Inductive coupling plasma spectrometry; Metalloproteins; Protein; Gel permeation chromatography; Ultraviolet detector; Technique; Argon; Copper; Detection; Sulfur; Mass spectrometry; Monitoring; Speciation
• ISSN: 0003-2700; 1520-6882; 1520-6882
• DOI: 10.1021/ac101128x

Among the hyphenated techniques used to probe and identify metalloproteins, size exclusion chromatography coupled to inductively coupled plasma mass spectrometry (SEC-ICP-MS) has shown to have a central place. However, the calibration of SEC columns reveals to be tedious and always involves UV detection prior to ICP-MS. The presence of sulfur in 98% of proteins allows their detection by quadrupole ICP-MS, despite the isobaric interference (16O16O) on S, by monitoring 32S16O at mass to charge ratio (m/z) 48. The formation of SO occurs spontaneously in the argon plasma but can be optimized by the introduction of oxygen gas into a reaction cell (RC) to achieve nM levels. In this article, sulfur detection was discussed upon instrumental conditions and S detection was then optimized by applying O2 as a reaction gas. SO formation was used to calibrate SEC columns without UV detection. This simple SEC-ICP-MS method was used for plasma copper proteins in plasma healthy subjects (HS) and an untreated Wilson disease (WD) patient. Copper proteins identified in healthy subjects were transcuprein, ceruloplasmin (Cp) and albumin. The method led to results in good agreement with other methods of determination. Copper bound to Cp in the WD patient was lowered with regard to the HS, and the exchangeable Cu was highly increased.