3 research outputs found
Ambient Surface Analysis of Organic Monolayers using Direct Analysis in Real Time Orbitrap Mass Spectrometry
A better characterization of nanometer-thick
organic layers (monolayers)
as used for engineering surface properties, biosensing, nanomedicine,
and smart materials will widen their application. The aim of this
study was to develop direct analysis in real time high-resolution
mass spectrometry (DART-HRMS) into a new and complementary analytical
tool for characterizing organic monolayers. To assess the scope and
formulate general interpretation rules, DART-HRMS was used to analyze
a diverse set of monolayers having different chemistries (amides,
esters, amines, acids, alcohols, alkanes, ethers, thioethers, polymers,
sugars) on five different substrates (Si, Si<sub>3</sub>N<sub>4</sub>, glass, Al<sub>2</sub>O<sub>3</sub>, Au). The substrate did not
play a major role except in the case of gold, for which breaking of
the weak Au–S bond that tethers the monolayer to the surface,
was observed. For monolayers with stronger covalent interfacial bonds,
fragmentation around terminal groups was found. For ester and amide-terminated
monolayers, in situ hydrolysis during DART resulted in the detection
of ions characteristic of the terminal groups (alcohol, amine, carboxylic
acid). For ether and thioether-terminated layers, scission of C–O
or C–S bonds also led to the release of the terminal part of
the monolayer in a predictable manner. Only the spectra of alkane
monolayers could not be interpreted. DART-HRMS allowed for the analysis
of and distinction between monolayers containing biologically relevant
mono or disaccharides. Overall, DART-HRMS is a promising surface analysis
technique that combines detailed structural information on nanomaterials
and ultrathin films with fast analyses under ambient conditions
Ambient Surface Analysis of Organic Monolayers using Direct Analysis in Real Time Orbitrap Mass Spectrometry
A better characterization of nanometer-thick
organic layers (monolayers)
as used for engineering surface properties, biosensing, nanomedicine,
and smart materials will widen their application. The aim of this
study was to develop direct analysis in real time high-resolution
mass spectrometry (DART-HRMS) into a new and complementary analytical
tool for characterizing organic monolayers. To assess the scope and
formulate general interpretation rules, DART-HRMS was used to analyze
a diverse set of monolayers having different chemistries (amides,
esters, amines, acids, alcohols, alkanes, ethers, thioethers, polymers,
sugars) on five different substrates (Si, Si<sub>3</sub>N<sub>4</sub>, glass, Al<sub>2</sub>O<sub>3</sub>, Au). The substrate did not
play a major role except in the case of gold, for which breaking of
the weak Au–S bond that tethers the monolayer to the surface,
was observed. For monolayers with stronger covalent interfacial bonds,
fragmentation around terminal groups was found. For ester and amide-terminated
monolayers, in situ hydrolysis during DART resulted in the detection
of ions characteristic of the terminal groups (alcohol, amine, carboxylic
acid). For ether and thioether-terminated layers, scission of C–O
or C–S bonds also led to the release of the terminal part of
the monolayer in a predictable manner. Only the spectra of alkane
monolayers could not be interpreted. DART-HRMS allowed for the analysis
of and distinction between monolayers containing biologically relevant
mono or disaccharides. Overall, DART-HRMS is a promising surface analysis
technique that combines detailed structural information on nanomaterials
and ultrathin films with fast analyses under ambient conditions