Surface-assisted laser desorption/ionization-mass spectrometry using TiO2-coated steel targets for the analysis of small molecules

Abstract

Matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) measurements in the low-molecular mass region, ranging from 0 to 1000 Daltons are very often difficult to perform because of signal interferences originating from matrix ions. In order to overcome this problem, a stainless steel target was coated with a homogeneous titanium dioxide layer. The layer obtained was further investigated for its ability to desorb small molecules, e.g. amino acids, sugars, polyethyleneglycol (PEG 200) or extracts from Cynara scolymus leaves. The stability of the layer was determined by repeated measurements on the same target location, which was monitored by X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) before and after surface assisted laser desorption/ionization (SALDI) analysis. In addition, the titanium dioxide layerwas compared with an already published method with titanium dioxide nanopowder as inorganic matrix. As a result of this work, the titanium dioxide layer produced minimal background interference, enabling simple interpretation of the detected mass spectra. Furthermore, the TiO2 coating provides a target that can be reused many times for SALDI-MS measurements.

Nanomaterials as Assisted Matrix of Laser Desorption/Ionization Time-of-Flight Mass Spectrometry for the Analysis of Small Molecules

“…Sonderegger et al [68] reported a method for analysis of small molecules by using a conventional MALDI steel target coated with a 50-nm TiO 2 layer. The layer without pores or islands was prepared by electron beam evaporation.…”

TiO2 Nanocoral Structures as Versatile Substrates for Surface‐Assisted Laser Desorption/Ionization Mass Spectrometry

“…TiO 2 occurs naturally as three polymorphs: anatase, brookite, and rutile, and these have different chemical and physical properties. To date, several SALDI‐MS analyses with TiO 2 substrates have been reported . Kawasaki et al.…”

Effect of polydimethylsiloxane (PDMS) coating on TiO2-based MALDI matrix for dimethyl methylphosphonate (DMMP) analysis

“…However, use of organic matrices for small molecule (<500 Da) analysis can be limited due to the interference by fragmentation of organic acid matrices upon laser irradiation yielding background signals at low masses [16][17][18]. To overcome this problem, several alternative matrices, such as carbon nanotube [19][20][21], surfactant-mediated matrix [22][23][24], graphene [25,26] and metal oxides [27][28][29][30][31][32] have been investigated. Among the alternatives, metal oxide nanoparticles have attracted great attention due to its high ability of photonabsorption, large surface area, low heat capacity and high stability during the laser irradiation process, resulting in low background signals in MALDI-MS.…”