The detection of active moulds on historical silk by the means of the headspace–solid phase micro-extraction–gas chromatography–mass spectrometry method

Abstract

The goal of this work was to analyze the profile of microbial volatile organic compounds (MVOCs) emitted by moulds growing on silk samples in search of particular volatiles mentioned in the literature as indicators of active mould growth. The selected moulds were inoculated on three types of media: (1) samples of pure silk placed on microbial media, (2) samples of historical silk placed on microbial media, and (3) agar containing amino acids that are elements of the structure of fibroin. All samples were prepared inside vials (closed system). In the first and second cases the media did not contain any sources of organic carbon, nitrogen, or sulfur—the silk was the only nutrient for the moulds. A fourth type of sample was historical silk prepared in a Petri dish without a microbial medium and inoculated with a fibroinolytically active mould (open system). The MVOCs emitted by moulds were sampled with the headspace–solid phase micro-extraction method. Volatiles extracted on Divinylbenzene/Carboxen/Polydimethylsiloxane (DVB/CAR/PDMS) fibers were analyzed in a gas chromatography–mass spectrometry system. Qualitative and quantitative analyses of chromatograms were carried out in search of indicators of metabolic activity. The results showed that there are three groups of volatiles that can be used for the detection of active forms of moulds on silk. Thus, this can be a valuable tool for the fast detection of mould activity on historical silk objects. To the best of our knowledge, this is the first work to measure MVOCs emitted by moulds growing on silk.