Extension of metal oxide laser ionization mass spectrometry to analytes with varied chemical functionalities

Abstract

Addition of a proton source to NiO enhanced the MOLI MS response for peptides, carbohydrates, and compounds in a crude oil sample. Efficient ionization of these samples effectively extended applications of MOLI MS beyond lipid analytes containing esters.

Analysis of carbohydrates and glycoconjugates by matrix‐assisted laser desorption/ionization mass spectrometry: An update for 2013–2014

“…NiO Particles treated with methyl acetate as a proton donor have been shown to act as matrices for a number of compound types, including 12 small carbohydrates. Proposed proton/sodium exchange in the ion source resulted in a mixture of [M + H] + and [M + Na] + ions but with a dramatic reduction in background peaks compared with the spectra recorded from DHB (McAlpin & Voorhees, ).…”

Laser desorption ionization of small molecules assisted by tungsten oxide and rhenium oxide particles

“…In many cases in previous literature, particles used for assisting in LDI have required pretreatment with chemical modification, etching, or with the addition of proton sources to achieve the desired signal . From the experiments performed in direct comparison with the high work function particles in our lab, the lower work function metals stainless steel (blank matrix) and untreated Fe 3 O 4 (SI Fig.…”

“…Other attempts have made use of metal oxides such as ZnO, MnO, CoO, WO 3 , TiO 2 , SnO 2 , Fe 3 O 4 , CaO, and NiO; and bare metals such as Au, Ag, Sn, and Al . Clearly, the use of metal oxides as a base for LDI has been investigated for several compounds, and the Vorhees' research lab, responsible for studies using CaO and NiO, have coined this work as metal oxide laser ionization mass spectrometry (MOLI) …”

“…Other attempts have made use of metal oxides such as ZnO, MnO, CoO, WO 3 , TiO 2 , SnO 2 , Fe 3 O 4 , CaO, and NiO; and bare metals such as Au, Ag, Sn, and Al. [32][33][34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49] Clearly, the use of metal oxides as a base for LDI has been investigated for several compounds, and the Vorhees' research lab, responsible for studies using CaO and NiO, have coined this work as metal oxide laser ionization mass spectrometry (MOLI). [47][48][49] In addition to the ability to efficiently absorb UV incident laser radiation and then transfer that energy to desorb and ionize a target analyte without any unintended ions formed, there are other characteristics of inorganic particles to consider that make them successful in assisting LDI of a target analyte.…”

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.…”