Isolation of individual capsaicinoids from a mixture and their characterization by 13C NMR spectrometry

Chromatography with silver nitrate: part 2

“…Overall a mixed stationary phase consisting of a phenyl-cation exchange, charged with silver ions, facilitated useful separation of the capsaicinoids, a method that was later refined by the same group. 41 In related work, not only in chemical structure but also in chromatographic technique, Liang Andersson 43 prepared silver (I)-mercaptopropano silica gel and evaluated its performance against crude oil and found that it allows an efficient group separation of polycyclic sulfur containing aromatic compounds (36)(37)(38)(39)(40)(41)(42). Size played an important role and separation fell into three bands (top, middle and below), with the most abundant having a single substituent containing a variety of unidentified eight carbon (C 8 ) atom isomers ( Figure 11).…”

Applications of argentation solid phase extraction to the capsaicinoids: Purification of commercial standards and isolation of homodihydrocapsaicin (8-methyl) from ‘Bhut Jolokia’

“…The first proton NMR spectrum of the 8-methyl isomer was recorded by Jurenitsch and Woeginger (1982), while improved 1 H NMR values were given by Maillard, Giampaoli, and Richard (1997). Our laboratory provided sets of 13 C NMR values for 15 capsaicinoid standards (Thompson et al, 2006). In this report the presence of homodihydrocapsaicin (8-methyl) in chili pepper is confirmed through measurement of the compound's 13 C NMR signature for the first time.…”

“…Most types of SCX cartridges can be used with some differences in performance (Thompson et al, 2006). We chose the Discovery product for this separation since it had a large capacity (0.28 milliequivalents per gram).…”

“…The following capsaicinoids in 'Bhut Jolokia' were identified by their reversed phase LC retention times, electrospray molecular ions, and 13 C NMR spectra in comparison to known standards (Thompson et al, 2006): nordihydrocapsaicin (7-methyl); capsaicin (6-ene-8-methyl); N-vanillylnonanamide; dihydrocapsaicin (8-methyl); N-vanillyldecanamide; homodihydrocapsaicin (9-methyl). We did not possess a known standard of homodihydrocapsaicin (8-methyl), so its identity had to be deduced.…”

“…Silver has also been incorporated into the stationary phase to good effect, either adsorbed onto reversed phase material for thin-layer chromatography (Wall, 1997) or complexed onto a mixed mode resin for analytical liquid chromatography (Thompson, Phinney, Sander, & Welch, 2005). ''Argentation solid phase extraction'' (argentation SPE) of the capsaicinoids is also possible with the silver ion bonded to a strong cation exchanger (Thompson, Pennino, Brenner, & Mehta, 2006).…”