Molecular Structure of Gardenia Blue Pigments by Reaction of Genipin with Benzylamine and Amino Acids

Genipin was reacted with benzylamine and several amino acids to prepare gardenia blue (GB). The time-course of GB formation with benzylamine was monitored by high-performance liquid chromatography (HPLC), liquid chromatography time-of-flight mass spectrometry (LC-TOFMS), and ¹H and ¹³C NMR measurements. In this experiment, we determined the molecular structures of some intermediates using accurate masses and additional NMR techniques such as heteronuclear multiple bond correlation (HMBC). GBs with amino acids (GB-AAs) were characterized by both liquid and solid-state NMR measurements. Interestingly, many significant peaks appeared in the solid-state NMR spectra, although the ¹³C NMR spectra from solution samples did not show any distinct peaks. Therefore, we determined that GB-AAs had an alternating copolymer structure composed of methyne and 5H-2-pyrindine, which was substituted by amino acids at N atom and linked with methyne at 5 and 7 positions. To confirm this molecular structure, the pyrolysis gas chromatography-mass spectrometry (GC-MS) measurement of GB-AAs was carried out, and 5H-2-pyrindine and its methyl derivatives were formed as main pyrolysis products from the polymer chains.

Pyrolyzable Nanoparticle Tracers for Environmental Interrogation and Monitoring

Environmental tracing applications require materials that can be detected in complex fluids composed of multiple phases and contaminants. Moreover, large libraries of tracers are necessary in order to mitigate memory effects and to deploy multiple tracers simultaneously in complex oil fields. Herein, we disclose a novel approach based on the thermal decomposition of polymeric nanoparticles comprised of styrenic and methacrylic monomers. Polymeric nanoparticles derived from these monomers cleanly decompose into their constituent monomers at elevated temperatures, thereby maximizing atom economy wherein the entire nanoparticle mass contributes to the generation of detectable units. A total of ten unique single monomer particles and three dual-monomer particles were synthesized using semicontinuous monomer starved addition polymerization. The pyrolysis gas chromatography-flame ionization detection/mass spectrometry (GC-FID/MS) behavior of these particles was studied using high-pressure mass spectrometry. The programmable nature of our methodology permits simultaneous removal of contaminants and subsequent identification and quantification in a single analytical step.