Characterization of Polyimides by Combining Mass Spectrometry and Selective Chemical Reaction

Abstract

Selective chemical reaction was employed to overcome problems related to molecular characterization of polyimides due to their insolubility. N-Methylethanolamine was used to induce ring opening, and chain cleavage was carried out by reaction with hydrazine. These reactions were used to enhance solubility of poly(trimellitic anhydride-co-4,4′-methylenedianiline), poly(pyromellitic dianhydrideco-4,4′-oxydianiline), and its amic acid form in MALDI and ESI friendly solvents, thus enabling their qualitative analysis by these techniques for the first time. Derivatives of poly(trimellitic anhydride-co-4,4′-methylenedianiline), made with 2-fluoro-1-methylpyridinium p-toluenesulfonate to introduce charge on the polymer, were used to increase ionization efficiency and intensity in positive ion MALDI spectra.

Detection and Mapping of Cannabinoids in Single Hair Samples through Rapid Derivatization and Matrix-Assisted Laser Desorption Ionization Mass Spectrometry

“…It was also noted that for all derivatized samples there was almost complete suppression of CHCA matrix-related peaks, as previously observed by Murgasova et al…”

“…Once the nature of the peak at m / z 313.22 was elucidated, in order to avoid rearrangement due to the laser energy, a chemical modification of THC was carried out. Derivatization has previously been identified as a possible strategy to improve signal intensity and decrease matrix interference. , …”

“…Derivatization has previously been identified as a possible strategy to improve signal intensity and decrease matrix interference. 42,43 The target for derivatization was the hydroxyl group, since all cannabinoids of interest contain this functional group. After careful review of the literature, the derivatization method using 2-fluoro-1-methylpyridinium p-tolunesolfonate (FMPTS) to form an N-methylpyridinium derivative, as reported by Quirke et al 36 for the detection of alcohols by ESI-MS, was chosen.…”

Soft ionization mass spectroscopy: Insights into the polymerization mechanism

“…This halohydrination is not seen with NaCl because chlorine is less nucleophilic than bromine or iodine 62. For polymers that are not easily ionizable, it may be necessary to chemically derivatized them prior to measurement 63–65. Instrument parameter settings can also play an important role in successful mass spectrometry measurement with parameters such as laser pulse rate, mass range, accelerating voltage, reflectron/linear mode (MALDI), and capillary voltage, spray voltage, capillary temperature (in the case of ESI) all shown to have dramatic impacts on the quality of MS spectra acquisition.…”

Detection and Mapping of Cannabis Use in Hair Samples Using Mass Spectrometry

“…In this study, the target for the derivatisation was the hydroxyl group, since all cannabinoids of interest contain this functional group. After carefully reviewing the literature, the derivatisation method using 2-Fluoro-1-Methylpyridinium p- moieties, in various sample types including surfactants [218], oestrogens [219] and the narcotic analgesic buprenorphine [220], using LC-MS analysis, and polyamides [221] and sterols [222] in MALDI profiling experiments. This strategy was selected due to the simplicity of the nucleophilic substitution reaction which occurs readily at room temperature [223], the stability of the products formed [218,224] and also the addition of a permanent charge to the analytes.…”