On the mechanism of ion desorption in the process of laser desorption/ionization from silicon surfaces

Grechnikov, A. A.; Borodkov, A. S.; Zhabin, S. N.; Alimpiev, S. S.

doi:10.1134/s1061934814140044

Cited by 8 publications

(7 citation statements)

References 11 publications

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“…The normalized total ion intensities for the four noble metal NPs increased with the laser fluence. A similar trend in the ion-desorption efficiency was also observed in our previous studies using different carbon allotropes as the SALDI substrates, and was consistent with the studies using silicon materials and other metal NPs as substrates. , It had been suggested that the higher laser fluence could enhance the photo energy deposition, thus facilitating the thermal desorption process via laser-induced heating of SALDI substrates. ,,,, Moreover, another possible reason could be the enhanced laser-induced phase transition with the increasing laser fluence. In fact, our previous study and several reports from other research groups have also revealed that laser-induced phase transition or surface restructuring/melting of SALDI substrates could facilitate the ion-desorption process. − ,, …”

Section: Resultssupporting

confidence: 89%

“…It is well-known that physicochemical properties of most inorganic nanomaterials are dependent on their sizes and/or morphologies. ,,− The variation of the physicochemical properties resulting from the different sizes or shape of the nanoparticles would lead to a different extent of laser energy deposition, and subsequent laser-induced heating and/or laser-induced phase transition; thus this affects the resultant desorption/ionization efficiency and internal-energy transfer in the SALDI process. ,,,− ,− A recent study using spherical AuNPs of 10 nm diameter showed a 10 times higher LDI efficiency than their 2 nm diameter counterparts for the detection of a cationized peptide (Substance P) . In another study, spherical AuNPs (30 nm diameter) showed a 2.8 times lower laser fluence threshold at 355 nm for the LDI of a synthetic polymer (PEG600) than AuNP nanorod (18 nm diameter × 50 nm length) .…”

Section: Introductionmentioning

confidence: 99%

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Ion-Desorption Efficiency and Internal-Energy Transfer in Surface-Assisted Laser Desorption/Ionization: More Implication(s) for the Thermal-Driven and Phase-Transition-Driven Desorption Process

et al. 2015

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Fundamental factors governing the ion-desorption efficiency and extent of internal-energy transfer to a chemical thermometer, benzylpyridinium ion ([BP] + ), generated in the surface-assisted laser desorption/ionization (SALDI) process, were systematically investigated using noble metal nanoparticles (NPs), including AuNPs, AgNPs, PdNPs, and PtNPs, as substrates, with an average particle size of 1.7−3.1 nm in diameter. In the correlation of ion-desorption efficiency and internal-energy transfer with physicochemical properties of the NPs, laser-induced heating of the NPs, which are dependent on their photoabsorption efficiencies, was found to be a key factor in governing the ion-desorption efficiency and the extent of internal-energy transfer. This suggested that the thermal-driven desorption played a significant role in the ion-desorption process. In addition, a stronger binding affinity of [BP] + to the surface of the NPs could hinder its desorption from the NPs, and this could be another factor in determining the ion-desorption efficiency. Moreover, metal NPs with lower melting points could also facilitate the ion-desorption process via the phase-transition process, which could lower the activation barrier (ΔG # ) of the iondesorption process by increasing the entropic change (ΔS # ). The study reveals that high photoabsorption efficiency, weak binding interaction with analyte molecule, and low melting point could be critical for the design of SALDI substrates with efficient ion desorption. ■ INTRODUCTIONSurface-assisted laser desorption/ionization (SALDI), a major branch of laser desorption/ionization (LDI) techniques, has been widely applied to mass spectrometry (MS) analysis of small molecules, and has become increasingly popular for analysis of environmental samples, forensic samples, drugs, metabolomics, and proteomics, and for imaging mass spectrometric analysis. 1−7 A key to its success is the adoption of effective substrates for the efficient absorption and controllable transfer of laser energy, which enables the efficient desorption/ionization of analyte molecules, without inducing extensive fragmentation and without introducing serious interfering background ions. Although SALDI-MS using carbon particles as the substrate was first developed in 1995, 8 the technique became popular after the introduction of nanostructured porous silicon surface as the substrate to attain a high LDI efficiency at low laser fluence. 9−11 Since then, different types and forms of inorganic-based nanomaterials, including silicon-based, 12−15 carbon-based, 1,8,16−21 and metalbased nanomaterials, 22−31 have been developed as SALDI substrates, though their analytical performances are varied and are highly dependent on their sizes, shapes, and surface properties.Fundamental study of the LDI process remains a challenging issue. While matrix-assisted laser desorption/ionization (MALDI), using organic acids as a matrix, has been developed since the 1980s, it took about two decades for its mechanism to become better studied and unde...

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Section: Resultssupporting

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Ion-Desorption Efficiency and Internal-Energy Transfer in Surface-Assisted Laser Desorption/Ionization: More Implication(s) for the Thermal-Driven and Phase-Transition-Driven Desorption Process

et al. 2015

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“…Although SALDI-MS is getting more popular, fundamental studies on the SALDI process remain relatively limited ,− when compared with the studies on its analytical applications. , A variety of silicon-based, carbon-based nanomaterials and metallic nanoparticles (NPs) have been reported as efficient SALDI substrates for LDI-MS analysis of small molecules, which complements the limitations of MALDI-MS for the low mass analyte analysis (<800 Da). ,− , It had been found that the analytical performance of SALDI-MS is highly dependent on the intrinsic physicochemical properties of SALDI substrates, ,,,,− such as photoabsorption efficiency, thermal conductivity, and melting point. All of these properties could be affected by the morphologies and types of SALDI substrates adopted.…”

Section: Introductionmentioning

confidence: 99%

Nanosecond UV Laser Ablation of Gold Nanoparticles: Enhancement of Ion Desorption by Thermal-Driven Desorption, Vaporization, or Phase Explosion

et al. 2016

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The phase transition of surface-assisted laser desorption/ionization (SALDI) substrates has been identified as a driving process for ion desorption in many previous SALDI fundamental studies. Here, the effects of various phase transition stages, including substrate melting, vaporization, and phase explosion, on SALDI ion desorption efficiency and extent of heat transfer were investigated. We employed molecular dynamics to simulate the phase transition (from melting, vaporization, to phase explosion) of gold nanoparticles (AuNPs, ⌀: 2.5 nm) upon laser-induced heating and experimentally probed the corresponding SALDI ion desorption efficiency and extent of heat transfer to a chemical thermometer, benzylpyridinium (BP) salt (using 355 nm solidstate laser, pulse width: 6 ns, laser fluence range: 21.3 to 125.9 mJ/cm 2 ). The results showed that substrate phase explosion has the most significant effect on enhancing the ion desorption efficiency and lowering the extent of heat transfer, which were reflected by an abrupt increase in both the ion desorption efficiency and the survival yield, when the laser fluence exceeded the AuNPs' phase explosion threshold temperature (5800 K). Compared with phase explosion, vaporization only exhibited a limited effect on the ion desorption efficiency, while the effect of melting was not noticeable and even overridden by the thermal-driven desorption. The significant effect of phase explosion on enhancing the ion desorption efficiency could be attributed to the weaker binding interaction between the BP ions and the Au atoms which were rapidly ablated during the phase explosion stage, and the cooling effect on the BP ions could be due to the adiabatic expansion of the ablation plume during the phase explosion. The study revealed that the SALDI substrate with a lower phase explosion threshold would have a higher potential in enhancing the analytical performance of SALDI-MS.

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“…The initial region, up to about 25 mJ/cm 2 , is characterized by a close to exponential increase of ion signal with an increase in the laser fluence and is probably due to the thermal nature of the desorption process. [18][19][20] In the second region, the ion signal is weakly dependent on the laser fluence, reaching saturation. At the third region, when the laser fluences are higher than 40 mJ/cm 2 , an increase in the laser fluence leads to a drop in the signal.…”

Section: Ways To Improve the Reproducibility Of The Analysismentioning

confidence: 99%

“…The protonated molecules are desorbed from the surface by laser-induced fast local heating of the surface. 18,19 Various alternative methods have been reported to prepare nanostructured silicon surfaces for SALDI, including plasma-enhanced chemical vapor deposition, 20 convective assembly coupled reactive ion etching, 21 magnetron sputtering, 18 glancing angle deposition, 22 laser treatment in an aqueous environment. 17 Many of these methods allow obtaining silicon substrates with high efficiency of ionization of various organic and bio-organic compounds, thus providing a high potential of silicon SALDI technique for solving a wide range of problems in the areas of proteomics, metabolomics, medical diagnostics, pharmacology, ecology, safeguarding.…”

Section: Introductionmentioning

confidence: 99%

Silicon surface assisted laser desorption ionization mass spectrometry for quantitative analysis

Grechnikov

Borodkov

Simanovsky

et al. 2021

Eur J Mass Spectrom (Chichester)

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The approach to quantitative analysis by silicon Surface Assisted Laser Desorption Ionization Mass Spectrometry (Si-SALDI) is proposed. The approach is based on the new method for forming an active surface layer on a silicon substrate by exposing to laser radiation directly in the ion source of a mass spectrometer. The method can be used repeatedly on the same substrate, providing high reproducibility of its surface ionization properties and high ionization efficiency of organic compounds. Within the proposed approach, the methods of improvement of signal reproducibility are also considered, including continuous monitoring of the silicon surface ionization properties using a Knudsen effusion cell; scanning the surface of a silicon substrate with a laser beam; selecting the optimal value of laser fluence and using a reproducible sample introduction technique. It is demonstrated that this approach can be successfully applied to quantify clinically relevant concentrations of pharmaceutical drugs in extracts of blood.

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On the mechanism of ion desorption in the process of laser desorption/ionization from silicon surfaces

Cited by 8 publications

References 11 publications

Ion-Desorption Efficiency and Internal-Energy Transfer in Surface-Assisted Laser Desorption/Ionization: More Implication(s) for the Thermal-Driven and Phase-Transition-Driven Desorption Process

Ion-Desorption Efficiency and Internal-Energy Transfer in Surface-Assisted Laser Desorption/Ionization: More Implication(s) for the Thermal-Driven and Phase-Transition-Driven Desorption Process

Nanosecond UV Laser Ablation of Gold Nanoparticles: Enhancement of Ion Desorption by Thermal-Driven Desorption, Vaporization, or Phase Explosion

Silicon surface assisted laser desorption ionization mass spectrometry for quantitative analysis

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