scholarly journals Pyrolysis - Field lonization Mass Spectrometry - A New Method for Direct, Rapid Characterization of Tobacco

1986 ◽  
Vol 13 (5) ◽  
pp. 219-227 ◽  
Author(s):  
HR Schulten
Keyword(s):  
Mass Spectrometry ◽  
High Vacuum ◽  
Principal Component ◽  
Hierarchical Cluster ◽  
Mass Range ◽  
Linear Mapping ◽  
Mapping Technique ◽  
Ionization Mass ◽  
Multivariate Statistical ◽  
Rapid Characterization

AbstractFor the first time, pyrolysis - field ionization (Py-FI) mass spectra of the tobacco blends of three different cigarette brands have been recorded in the mass range up to 1000 mass units and evaluated by operational fingerprinting techniques. Due to the high reproducibility of the applied methods, all three tobacco blends could be differentiated clearly with several univariate or multivariate statistical methods. Feature scaling with Fisher ratios revealed that the signal at m/z 93, mainly due to aniline, is the most suited to distinguishing the tobacco blends analysed. Principal component analysis showed the variety of pyrolytic reactions during the thermal decomposition of tobacco in high vacuum. It revealed that, in addition to aniline, lignin-related signals can also be used for a clear differentiation. From the whole pattern of Py-FI mass spectrum, nearest-neighbour relationships are visualized by the non-linear mapping technique and further classification of tobacco blends is obtained by hierarchical cluster analysis. A thorough chemical interpretation of the data obtained should give new insights into the structure of tobacco and its pyrolytic decomposition. Pyrolysis - soft ionization mass spectrometry in combination with pattern recognition techniques appears to provide a useful tool for future investigations connected with the quality control of commercial tobacco products.

scholarly journals Discovery of Spatial Peptide Signatures for Neuroblastoma Risk Assessment by MALDI Mass Spectrometry Imaging

Cancers ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 3184
Author(s):  
Zhiyang Wu ◽  
Patrick Hundsdoerfer ◽  
Johannes H. Schulte ◽  
Kathy Astrahantseff ◽  
Senguel Boral ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Risk Assessment ◽  
Mass Spectrometry Imaging ◽  
Principal Component ◽  
Therapy Resistance ◽  
Risk Classification ◽  
Intratumor Heterogeneity ◽  
Ionization Mass ◽  
Characteristic Analysis ◽  
Analytical Strategy

Risk classification plays a crucial role in clinical management and therapy decisions in children with neuroblastoma. Risk assessment is currently based on patient criteria and molecular factors in single tumor biopsies at diagnosis. Growing evidence of extensive neuroblastoma intratumor heterogeneity drives the need for novel diagnostics to assess molecular profiles more comprehensively in spatial resolution to better predict risk for tumor progression and therapy resistance. We present a pilot study investigating the feasibility and potential of matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI) to identify spatial peptide heterogeneity in neuroblastoma tissues of divergent current risk classification: high versus low/intermediate risk. Univariate (receiver operating characteristic analysis) and multivariate (segmentation, principal component analysis) statistical strategies identified spatially discriminative risk-associated MALDI-based peptide signatures. The AHNAK nucleoprotein and collapsin response mediator protein 1 (CRMP1) were identified as proteins associated with these peptide signatures, and their differential expression in the neuroblastomas of divergent risk was immunohistochemically validated. This proof-of-concept study demonstrates that MALDI-MSI combined with univariate and multivariate analysis strategies can identify spatially discriminative risk-associated peptide signatures in neuroblastoma tissues. These results suggest a promising new analytical strategy improving risk classification and providing new biological insights into neuroblastoma intratumor heterogeneity.

Rapid characterization of organic UV filters and their photoproducts in sunscreens by thermal desorption electrospray ionization mass spectrometry for the photostability study

2019 ◽  
Vol 11 (47) ◽  
pp. 6013-6022 ◽  
Author(s):  
Yi-Tzu Cho ◽  
Hung Su ◽  
I-Ching Huang ◽  
Ching-Yu Lai ◽  
You-Da Tsai
Keyword(s):  
Mass Spectrometry ◽  
Electrospray Ionization ◽  
Thermal Desorption ◽  
Electrospray Ionization Mass Spectrometry ◽  
Desorption Electrospray Ionization ◽  
Ionization Mass ◽  
Uv Filters ◽  
Rapid Characterization ◽  
Organic Uv Filters

UV filters and their photoproducts in sunscreen formulations are directly characterized by TD-ESI/MS. This is a highly viable strategy to study the photostability of highly complex and diverse sunscreen formulations in the market.

Shotgun Sequencing Small Oligonucleotides by Nozzle-Skimmer Dissociation and Electrospray Ionization Mass Spectrometry

2005 ◽  
Vol 11 (2) ◽  
pp. 221-229 ◽  
Author(s):  
Zhaojing Meng ◽  
Patrick A. Limbach
Keyword(s):  
Mass Spectrometry ◽  
Electrospray Ionization ◽  
Electrospray Ionization Mass Spectrometry ◽  
De Novo ◽  
De Novo Sequencing ◽  
Ionization Mass Spectrometry ◽  
Ionization Mass ◽  
Minimal Component ◽  
Rapid Characterization ◽  
Sequential Generation

Nozzle-skimmer dissociation in combination with de novo sequencing was investigated as an approach for increasing the throughput of oligonucleotide analysis attainable by electrospray ionization mass spectrometry. An experimental method allowing for the sequential generation of precursor and fragment ion data during direct infusion of samples was developed. These data can then be used with readily available de novo sequencing software to characterize small oligonucleotides. When this approach was applied to mixtures of oligonucleotides, it was found that de novo sequencing becomes limited due to spectral congestion and overlapping oligonucleotide m/z dissociation product values. Self-packed C18 microspray emitters were investigated as a means of reducing spectral complexity. It was found that such emitters allow for the analysis of oligonucleotide mixtures with minimal component overlap, and these emitters provide additional benefits of pre-concentrating and desalting the sample. These developments can provide a route for the more rapid characterization of ribonucleic acid endonuclease digestion mixtures.

scholarly journals Groundwater quality assessment using principal component analysis and hierarchical cluster analysis in Alaçam, Turkey

2021 ◽  
Author(s):  
Mehmet Taşan ◽  
Yusuf Demir ◽  
Sevda Taşan
Keyword(s):  
Principal Component Analysis ◽  
Cluster Analysis ◽  
Groundwater Quality ◽  
Seawater Intrusion ◽  
Hierarchical Cluster Analysis ◽  
Principal Component ◽  
Hierarchical Cluster ◽  
Component Analysis ◽  
Quality Parameters ◽  
Multivariate Statistical

Abstract This study assessed groundwater quality in Alaçam, where irrigations are performed solely with groundwaters and samples were taken from 35 groundwater wells at pre and post irrigation seasons in 2014. Samples were analyzed for 18 water quality parameters. SAR, RSC and %Na values were calculated to examine the suitability of groundwater for irrigation. Hierarchical cluster analysis and principal component analysis were used to assess the groundwater quality parameters. The average EC value of groundwater in the pre-irrigation period was 1.21 dS/m and 1.30 dS/m after irrigation in the study area. It was determined that there were problems in two wells pre-irrigation and one well post-irrigation in terms of RSC, while there was no problem in the wells in terms of SAR. Piper diagram and cluster analysis showed that most groundwaters had CaHCO3 type water characteristics and only 3% was NaCl- as the predominant type. Seawater intrusion was identified as the primary factor influencing groundwater quality. Multivariate statistical analyses to evaluate polluting sources revealed that groundwater quality is affected by seawater intrusion, ion exchange, mineral dissolution and anthropogenic factors. The use of multivariate statistical methods and geographic information systems to manage water resources will be beneficial for both planners and decision-makers.

scholarly journals Water quality assessment and geochemical processes in the unconfined coastal Boa Viagem Aquifer, Recife, NE Brazil

2021 ◽  
pp. 56-77
Author(s):  
Thyego Silva ◽  
Mariucha Lima ◽  
Teresa Leitão ◽  
Tiago Martins ◽  
Mateus Albuquerque
Keyword(s):  
Water Quality ◽  
Quality Assessment ◽  
Principal Component ◽  
Hierarchical Cluster ◽  
Water Quality Assessment ◽  
Multivariate Statistical Analyses ◽  
Multivariate Statistical ◽  
Rock Interaction ◽  
Groundwater Samples ◽  
Water Rock Interaction

A hydrochemical study was conducted on the Quaternary Aquifer, in Recife, Brazil. Groundwater samples were collected in March–April 2015, at the beginning of the rainy season. Conventional graphics, ionic ratios, saturation indices, GIS mapping, and geostatistical and multivariate statistical analyses were used to water quality assessment and to characterize the main hydrochemical processes controlling groundwater’s chemistry. Q-mode hierarchical cluster analysis separated the samples into three clusters and five sub-clusters according to their hydrochemical similarities and facies. Principal Component Analysis (PCA) was employed to the studied groundwater samples where a three-factor model explains 80% of the total variation within the dataset. The PCA results revealed the influence of seawater intrusion, water-rock interaction, and nitrate contamination. The physico-chemical parameters of ~30% groundwaters exceed the World Health Organization (WHO) guidelines for drinking water quality. Nitrate was found at a concentration >10 mg NO3−/L in ~21% of the wells and exceeded WHO reference values in one. The integrated approach indicates the occurrence of the main major hydrogeochemical processes occurring in the shallow marine to alluvial aquifer as follow: 1) progressive freshening of remaining paleo-seawater accompanying cation exchange on fine sediments, 2) water-rock interaction (i.e., dissolution of silicates), and 3) point and diffuse wastewater contamination, and sulfate dissolution. This study successfully highlights the use of classical geochemical methods, GIS techniques, and multivariate statistical analyses (hierarchical cluster and principal component analyses) as complementary tools to understand hydrogeochemical processes and their influence on groundwater quality status to management actions, which could be used in similar alluvial coastal aquifers.

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