High Resolution Mass Spectrometry coupled to Ion Mobility Spectrometry for the analysis of Complex Matrix
Name: LILIAN VALADARES TOSE
Type: PhD thesis
Publication date: 16/08/2018
Advisor:
Name |
Role |
|---|---|
| WANDERSON ROMÃO | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| ÁLVARO CUNHA NETO | Internal Examiner * |
| FRANCISCO ALBERTO FERNANDEZ LIMA | External Examiner * |
| GLORIA MARIA DE FARIAS VIÉGAS AQUIJE | External Examiner * |
| RICARDO MACHADO KUSTER | Internal Examiner * |
| WANDERSON ROMÃO | Advisor * |
Summary: Mass spectrometry (MS) is a technique able to ionize simple molecules until complex
structures, performing efficiently and dynamically with a wide application using high
sensitivity and speed of analysis. Although MS has considerable interest in the scientific
society, the application of new technologies in the field of complex matrix analysis still
is little explored.
In analyzes of crude oil, paraffin and condensed aromatic standards, the atmospheric
solids analysis probe mass spectrometry (ASAP-MS) is a powerful ionization source for
characterization of samples in original form. Initially, two methodologies were used to
determine the chemical composition of the samples: (1) using a temperature gradient
ranging from 150 to 600 °C at a heating rate of 150 °C.min-1 (parafina) or 50 °C.min-1;
(2) with a constant temperature around 350 °C. ASAP(+)-MS ionized crude oil and
paraffin, showing a typical petroleum profile in the range of m/z 200 - 1400 for both
samples. This performance could relate ASAP source to detection of compounds of high
molecular weight (> 1000 Da). In addition, the AC standards were identified in two
ionic forms: radicals, [M]+ and protonated cations, [M+H]+, with minimal
fragmentation. Therefore, ASAP was efficient for accessing the chemical composition
of polar and non-polar compounds.
Analysis of the Cannabis sativa L. plant, were doing by ultra-high performance liquid
chromatography coupled to traveling wave ionic mass spectrometry (UPLC-TWIMS
MS) using electrospray ionization source in both modes, ESI (±). Hashish, marijuana,
and parts of the plant Cannabis sativa L. (flower and leaf) were analyzed. Isomeric
compounds were identified in a complex mixture of cannabinoids, mainly Δ9-THC,
cannabidiol (CBN-C5 and Mw = 310 Da), Δ9-tetrahydrocannabinolic acid A and B (Δ9-
THCA-C5 A/B and Mw = 358 Da) and their isomers. Analizes by ESI-TWIMS MS were
identified three isomers, m/z 315/313, 311, and 357, while a high selectivity was
observed in UPLC-ESI-TOF MS data, identifying more than four isomeric compounds
in the single ion acquisition mode (SIM).
In other study, we evaluated the use of a high resolution mobility analyzer coupled to
ultra high resolution mass spectrometry for molecular characterization of dissolved
organic matter. The main goal was to validate the reproducibility of trapped ion
mobility spectrometry (TIMS), the range of applicability and possible challenges during
routine analysis. TIMS coupled to TOF MS and FT-ICR MS showed similar performance and high reproducibility. For the analysis of complex mixtures, both
platforms were able to aquiried the main characteristics. However, the increase of
chemical complexity at nominal mass level (m/z > 300 - 350), only TIMS-FT-ICR MS
was able to solve the compositional tendencies of lower abundance.
