MALDI-TOF mass spectrometry-based quantification of C-peptide in diabetes patients

Mei Hua Wan, Yichao Wang, Lingpeng Zhan, Jia Fan, Tony Y. Hu

Research output: Contribution to journalArticle

Abstract

Background: Serum C-peptide concentrations reflect insulin secretion and beta cell function and can be used to diagnose and distinguish type-1 and type-2 diabetes. C-peptide is a more accurate indicator of insulin status than direct insulin measurement for monitoring patients with diabetes. However, the current methods available for C-peptide quantification exhibit poor reproducibility, are costly, and require highly trained laboratory personnel. Here, we have developed and evaluated a matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS)-based assay to standardize C-peptide measurements, providing highly accurate and comparable results across testing systems and laboratories. Methods: C-peptide from human serum was enriched using antibody-conjugated magnetic beads. The eluted isolates were further modified with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) to enhance the ionization of naturally acidic C-peptide. After desalting with ZipTips, the samples were subjected to MALDI-TOF MS analysis. Recombinant human C-peptide was used to develop the assay, and a heavy isotope labeled human C-peptide was used as an internal standard for quantification. Results: The MALDI-TOF MS method was validated in accordance with the restrictions of the device, with a limit of quantitation of 25 pmol/L. A correlation between the MAL-DI-TOF MS assay and a reference method was conducted using patient samples. The resulting regression revealed good agreement. Conclusions: A simple, high-throughput, cost effective and quantitative MALDI-TOF MS C-peptide assay has been successfully developed and validated in clinical serum samples.

Original languageEnglish (US)
JournalEuropean Journal of Mass Spectrometry
DOIs
StateAccepted/In press - Jan 1 2019

Keywords

  • 6-Aminoquinolyl-N-hydroxysuccinimidyl carbamate
  • C-peptide
  • diabetes
  • immunoaffinity enrichment
  • ionization
  • MALDI-TOF MS

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics
  • Spectroscopy

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