A precise self‐built secondary mass database for identifying red dyes and dyeing techniques with UPLC‐MS/MS

Abstract

Dyes on ancient silks have been a worth studying field through human's history, although current reports ignore the connection between natural dyes origin and relevant colour reduction methods, which poses an insurmountable obstacle for restoration of historical silks. In this paper, a series of 12 red hue silks from six natural dyes (sappanwood, Chinese madder, safflower, lac, cochineal, dragon's blood) via three different dyeing techniques were used to establish a self‐built precise tandem mass spectrometry (MS/MS) database. With organic solvent extracting on those manual‐dyed silks, ultraperformance liquid chromatography ‐ electrospray ionization ‐ quadrupole time of flight mass spectrometry (UPLC‐ESI‐QTOF‐MS) was utilized to form preliminary MS database for screening and identifying of the potential dyes compounds without standard references. Furthermore, combining the targeted MS/MS mode and the matching threshold of 70.00, a self‐built secondary MS/MS database was successfully established, which contains 33 compounds, 32 chromatograms and 32 MS/MS fragments. As for real sample application, the self‐built precise MS/MS database had revealed that the dyes on two historical silks (Shanghai Museum, China) belong to Chinese madder just with different mordant dyeing ordinal. Additionally, by experimental restoration, visually indistinguishable silks (ΔEab* < 1.5 NBS) were successfully restored. This explorative methodology can further inspire the traceability of biological dyestuffs, which lays instructive foundation on protection and restoration of artefacts, connecting the archaeological science and human art.

Dye Identification in Mounting Textiles of Traditional Korean Paintings from the Late Joseon Dynasty

“…The conservation process of these paintings provided us with the opportunity to take small samples and apply high-pressure liquid chromatography coupled with diode array and tandem mass spectrometry detectors (HPLC-DAD-MS/MS). This is considered the state-of-the-art technique for identifying natural and synthetic dyes at a molecular level [22][23][24][25][26][27][28][29]. The technique requires minimal sampling (1-2 mm of a single thread) and provides insight into the molecular composition of dyes and dye mixtures, which is fundamental information for achieving straightforward identifications [11,[30][31][32].…”