The characterisation of shellac resin by flow injection and liquid chromatography coupled with electrospray ionisation and mass spectrometry

Abstract

A strategy based on electrospray ionisation (ESI) in negative mode coupled with quadrupole-time of flight (Q-ToF) detection techniques was adopted to characterise some samples of shellac resin. Flow injection analysis (FIA) was used to investigate the distribution of the components of the resin. Eight groups of compounds with increasing masses were detected and assigned to free acids, esters and polyesters with up to eight units. High pressure liquid chromatography (HPLC) enabled the compounds to be chromatographically separated. Accurate molecular masses and tandem mass (MS/MS) spectra interpretation were used to characterise the different compounds, assigning and/or suggesting molecular structures. In some cases, highly detailed information about the ester linkages was provided by the MS/MS spectra, enabling the different isomers to be distinguished. Oxidation products were also identified in the samples and differences were observed in terms of hydrolysis and oxidation. In addition to providing the first characterisation of shellac by HPLC-ESI-Q-ToF and an atlas of MS/MS spectra of shellac components, this work demonstrates the suitability of the proposed strategy for characterising the resin, and provides the identification of previously unknown degradation products and minor components. This represents a significant step forward in the chemical knowledge of this material.

Wax‐based delivery systems: Preparation, characterization, and food applications

“…Shellac is a food grade resin separated from secretions of Laccifer Lacca Kerr‐a parasite of certain trees like Butea frondosa Rosch, Vachellia nilotica , and Ficus religiosa Linn, mostly located in the forests of India, Thailand, Myanmar, and south China (Tamburini, Dyer, & Bonaduce, 2017). Shellac is a complex mixture of resin (70% to 80%), wax (6% to 7%), and colorant molecules (4% to 8%), depending on host tree, insect type, and environmental condition.…”

Magic Lantern Glass Slides Materials and Techniques: The First Multi-Analytical Study

“…Their infrared spectra displayed a CH stretching profile with bands at 2930 and 2856 cm -1 , a broad C = O stretching band centered at 1716 cm -1 , an NH bending/CC stretching band at 1637 cm -1 , and C-O stretching bands of carboxylic acids at 1253 and 1040 cm -1 ( Figure 8B) [33,34]. However, the presence of other binding media cannot be excluded, and further analyses, such as pyrolysis-gas chromatography/ mass spectrometry (Py-GC/MS), must be carried out in order to fully characterize the organic media present and their role in the painting process [35].…”

“…Shellac is a natural resin derived from the resinous secretion of the lac insect (Laccifer lacca) that has a very complex composition with mixtures of different mono and polyesters of hydroxyaliphatic and sesquiterpenoid acids [35]. During the nineteenth century, methods for decolorizing shellac resin, such as chemical bleaching, were developed and one of the resulting products was commonly known as white lac varnish [36].…”

Was Lacquer the Key Ingredient for Luxurious Jinyin Pingtuo Products in the Tang Dynasty of China (AD 618–907)?

“…The chemical composition of the shellac resin is very different from the Asian lacquers, as it is mainly composed of polyesters of aliphatic hydroxycarboxylic acids and sesquiterpenoid acids (Tamburini et al . ).…”