# What Are the Key Factors for the Detection of Peptides Using Mass Spectrometry on Boron-Doped Diamond Surfaces?

## TL;DR

This study explores how different boron-doped diamond surfaces improve peptide detection using mass spectrometry, especially for hydrophobic and acidic peptides.

## Contribution

The paper introduces a novel comparison of nanostructured boron-doped diamond surfaces with different terminations for MALDI-MS peptide detection.

## Key findings

- Hydrogen-terminated BDD surfaces effectively detect hydrophobic peptides like bradykinin 1–7 and substance P.
- Oxygen- and fluorine-terminated BDD surfaces are better for detecting acidic peptides like adrenocorticotropic hormone fragment 18–39.
- BDD surfaces significantly reduce sodium adduct contamination compared to standard surfaces.

## Abstract

We investigated the use of boron-doped diamond (BDD) with different surface morphologies for the enhanced detection of nine different peptides by matrix-assisted laser desorption/ionisation mass spectrometry (MALDI-MS). For the first time, we compared three different nanostructured BDD film morphologies (Continuous, Nanograss, and Nanotips) with differently terminated surfaces (-H, -O, and -F) to commercially available Ground Steel plates. All these surfaces were evaluated for their effectiveness in detecting the nine different peptides by MALDI-MS. Our results demonstrated that certain nanostructured BDD surfaces exhibited superior performance for the detection of especially hydrophobic peptides (e.g., bradykinin 1–7, substance P, and the renin substrate), with a limit of detection of down to 2.3 pM. Further investigation showed that hydrophobic peptides (e.g., bradykinin 1–7, substance P, and the renin substrate) were effectively detected on hydrogen-terminated BDD surfaces. On the other hand, the highly acidic negatively charged peptide adrenocorticotropic hormone fragment 18–39 was effectively identified on oxygen-/fluorine-terminated BDD surfaces. Furthermore, BDD surfaces reduced sodium adduct contamination significantly.