scholarly journals Chemical Images on Fingerprints Revealed with Mass Spectrometry

2021 ◽  
Vol 11 (12) ◽  
pp. 5624
Author(s):  
Andrea Carrà ◽  
Luigi Falciola ◽  
Giuseppe Cappelletti ◽  
Lavinia Morosi ◽  
Enrico Davoli
Keyword(s):  
Mass Spectrometry ◽  
Credit Cards ◽  
Detection Limits ◽  
Laser Desorption ◽  
Mass Region ◽  
Ionization Mass ◽  
Laser Desorption Ionization ◽  
Desorption Ionization ◽  
Low Mass ◽  
Endogenous Lipids

Commercially available UV-adsorbent TiO2 nanoparticles were used to assist laser/desorption ionization in the course of matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI). Titanium nano-powders proved extremely stable and efficient for small molecule ionization, with negligible background noise in the low mass region (m/z < 500 Da). Validation steps were carried out, assessing detection limits and comparing the results to those of the established DESI/Orbitrap technique. The new analytical method was used to reveal the molecular distribution of endogenous (lipids) and exogenous (analgesics and antipyretics) compounds in latent finger marks (LFMs). The detection limits of endogenous fatty acids and small molecules such as caffeine were in the range of fmol/mm2 on LFMs. The technique separated overlapping latent finger marks, exploiting the differences in lipid expression of human skin. Finally, the method was used to prove contact between skin and objects contaminated by different substances, such as credit cards and paper clips, with chemical images that maintain the shape of the objects on the LFM.

Functionalized Titanium Oxide Nanowire Substrate for Surface-Assisted Laser Desorption/ionization Imaging Mass Spectrometry

2019 ◽  
Author(s):  
Ewelina P. Dutkiewicz ◽  
Han-Jung Lee ◽  
Cheng-Chih Hsu ◽  
Yu-Liang Yang
Keyword(s):  
Mass Spectrometry ◽  
Secondary Metabolites ◽  
Imaging Mass Spectrometry ◽  
Detection Limits ◽  
Laser Desorption ◽  
Maldi Ms ◽  
Ionization Mass ◽  
Laser Desorption Ionization ◽  
Powerful Technique ◽  
Desorption Ionization

Imaging mass spectrometry (IMS) is a powerful technique that enables analysis of various molecular species at a high spatial resolution with low detection limits. In contrast to the standard matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) approach, surface-assisted laser desorption/ionization (SALDI) is more effective in the detection of small molecules due to the absence of interfering background signals in low <i>m/z</i> ranges. We developed a functionalized TiO<sub>2</sub> nanowire as a solid substrate for IMS of low-molecular-weight species in biological specimens. We prepared TiO<sub>2</sub> nanowires using the inexpensive modified hydrothermal process and subsequently functionalized it chemically with various silane analogs to overcome the problem of superhydrophilicity of the substrate. Chemical modification changed the selectivity of imprinting of samples deposited on the surface of the plate and thus improved the detection limits. Due to the enhanced performance, the functionalized TiO<sub>2</sub> nanowire substrate could be successfully used for imaging of complex native samples. We applied our new substrate to image distribution of the secondary metabolites in (1) petal of the medicinal plant <i>Catharanthus roseus</i> and (2) microbial co-culture of <i>Burkholderia</i> <i>cenocepacia </i>869T2 vs <i>Phellinus noxius</i>. We observed that secondary metabolites are distributed heterogeneously in a petal, which is consistent with previous results reported for the <i>C. roseus</i> plant leaf and stem. We verified the semi-quantitative capabilities of the imprinting/imaging approach by comparing results using standard LC-MS analysis of the plant extracts. Several bacteria-related metabolites produced by <i>B</i>. <i>cenocepacia</i> 869T2 in presence of <i>P. noxius</i>, which were unable to be detected by MALDI-MS approach, were revealed by our newly developed approach. This suggested that the functionalized TiO<sub>2</sub> nanowire substrates-based SALDI is a powerful technique complementary to MALDI-MS.

Functionalized Titanium Oxide Nanowire Substrate for Surface-Assisted Laser Desorption/ionization Imaging Mass Spectrometry

2019 ◽  
Author(s):  
Ewelina P. Dutkiewicz ◽  
Han-Jung Lee ◽  
Cheng-Chih Hsu ◽  
Yu-Liang Yang
Keyword(s):  
Mass Spectrometry ◽  
Secondary Metabolites ◽  
Imaging Mass Spectrometry ◽  
Detection Limits ◽  
Laser Desorption ◽  
Maldi Ms ◽  
Ionization Mass ◽  
Laser Desorption Ionization ◽  
Powerful Technique ◽  
Desorption Ionization

Imaging mass spectrometry (IMS) is a powerful technique that enables analysis of various molecular species at a high spatial resolution with low detection limits. In contrast to the standard matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) approach, surface-assisted laser desorption/ionization (SALDI) is more effective in the detection of small molecules due to the absence of interfering background signals in low <i>m/z</i> ranges. We developed a functionalized TiO<sub>2</sub> nanowire as a solid substrate for IMS of low-molecular-weight species in biological specimens. We prepared TiO<sub>2</sub> nanowires using the inexpensive modified hydrothermal process and subsequently functionalized it chemically with various silane analogs to overcome the problem of superhydrophilicity of the substrate. Chemical modification changed the selectivity of imprinting of samples deposited on the surface of the plate and thus improved the detection limits. Due to the enhanced performance, the functionalized TiO<sub>2</sub> nanowire substrate could be successfully used for imaging of complex native samples. We applied our new substrate to image distribution of the secondary metabolites in (1) petal of the medicinal plant <i>Catharanthus roseus</i> and (2) microbial co-culture of <i>Burkholderia</i> <i>cenocepacia </i>869T2 vs <i>Phellinus noxius</i>. We observed that secondary metabolites are distributed heterogeneously in a petal, which is consistent with previous results reported for the <i>C. roseus</i> plant leaf and stem. We verified the semi-quantitative capabilities of the imprinting/imaging approach by comparing results using standard LC-MS analysis of the plant extracts. Several bacteria-related metabolites produced by <i>B</i>. <i>cenocepacia</i> 869T2 in presence of <i>P. noxius</i>, which were unable to be detected by MALDI-MS approach, were revealed by our newly developed approach. This suggested that the functionalized TiO<sub>2</sub> nanowire substrates-based SALDI is a powerful technique complementary to MALDI-MS.

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