Dataset supporting the identification of natural dyes in yellow, orange, brown and green fibres from Krakow liturgical vestments

This data article provides an extensive and complete description of the colorants and dyes identified in fibre samples taken from the historical textiles that were described in the article "Universal analytical method for characterization of yellow and related natural dyes in liturgical vestments from Krakow” by K. Lech [1]. Natural organic dyes, for centuries used to dye fibres, contain usually from a few to several dyeing compounds. The correct identification of the dye requires at first the identification of their colouring components using sensitive and selective analytical techniques. One of this technique is high-performance liquid chromatography combined with spectrophotometric detection and detection using tandem mass spectrometry with electrospray ionization (HPLC-UV-Vis-ESI MS/MS). The HPLC-UV-Vis-ESI MS/MS protocol was used to identify natural dyes present in 89 yellow, orange, brown and green fibres taken from 15th- to 17th-century silk textiles used in vestments belonging to the collections of seventeen churches in Krakow, Poland.


Specifications table
Analytical Chemistry Specific subject area Identification of yellow, orange and brown dyes natural in historical textiles Type of data Raw LC-MS data Table  How data were acquired High-performance liquid chromatograph (1220 Infinity II LC System, Agilent Technologies) coupled with two spectrophotometric detectors (1220 Compact VWD and 1200 VWD, Agilent Technologies) and tandem mass spectrometric detector (6460 Triple Quad LC/MS with JetStream Technology, Agilent Technologies) Data format Raw and analysed Parameters for data collection Yellow, orange, brown and green fibres from 15th-to 17th-century silk textiles used in the vestments belonging to the collections of seventeen churches in Krakow Description of data collection Fibre extracts were analysed on the presence of natural colourants by HPLC-UV-Vis-ESI MS/MS using positive and negative dynamic multiple reaction monitoring (dMRM) modes. Brown and green fibres were extracted twice with DMSO and with acidic-methanol solution, whereas yellow and orange fibres were extracted only using the second procedure. Data

Value of the data
• These data support identification of natural dyes in historical vestments by identification of the colourants using HPLC-UV-Vis-ESI MS/MS • The dataset informs on natural dyes used in historical textiles from the 15th to the 17th centuries • These data can be valuable for conservators and art historians • The dataset increases knowledge on the historical vestments from Krakow churches

Data Description
Twofold extracts of 89 yellow, orange, brown and green fibres taken from historical textiles have been examined by HPLC-UV-Vis-ESI MS/MS using previously developed method [1] in dynamic multiple reaction monitoring (dMRM) mode. The silk textiles are dated from the 15th to the 17th centuries and they have been used in vestments belonging to the collections of seventeen Krakow churches. The DMSO extracts have been analysed using positive ion mode, whereas methanol-water-formic acid extracts have been examined with both positive and negative ion modes. Identification of the colorants have been based on the compatibility of their retention times and MRM transitions with standards and natural dye markers. Acquired results have led to identification of natural dyes in the examined fibres, even though some of them were re-dyed with synthetic dyes. All samples, their details and attributions, as well as identified colorants and dyes are listed in Table 1 . Original dataset is available in the repository [2] . green   bold and underlined -main compounds; bold -secondary compounds; non-highlighted -minor compounds; glc -glucoside, hex -hexoside, glcr -glucuronide, braz1 − brazilwood compound 1, braz2 − brazilwood compound 2, braz3 − brazilwood compound 3, braz4 − brazilwood compound 4, braz5 − brazilwood compound 5, braz6 − brazilwood compound 6, mad-der1 -madder compound 1, madder2 -madder compound 2, madder3 -madder compound 3, orchil1 -orchil compound 1, orchil2 -orchil compound 2, orchil3 -orchil compound 3, orchil4 -orchil compound 4; * detailed data presented in "KATALOG TKANIN z zasobów ko ścielnych Krakowa z czasów od XV do ko ńca XVII" (in Polish), Natalia Krupa (ed.), Kraków (in printing); textile origin and dating have been established by: 1 N. Krupa, 2 A. Warzecha 3 K. Moskal 4 B. Biedro ńska-Słota # initial inventory number of the object

Experimental Design, Materials, and Methods
The 89 silk fibres (yellow, orange, brown and green) were taken from 15th-to 17th-century silk textiles used in vestments belonging to the collections of seventeen Krakow churches (all samples are listed in Table 1 ).
Brown and green fibres were extracted twice, using two extraction methods consecutively, the first one with dimethylsulfoxide (DMSO), and the second one with acidic-methanol extractant. Yellow and orange fibres were extracted only with the second procedure. Extraction procedure have been described in detail by Lech [1] .
Separation of the colorants was carried out using a 1220 Infinity II LC Systems (Agilent Technologies, USA), whereas their identification was achieved with two spectrophotometric detectors, a 1220 Compact Variable Wavelength Detector (Agilent Technologies, Germany) and a 1200 Variable Wavelength Detector (Agilent Technologies, Germany), as well as with a 6460 Triple Quad tandem mass spectrometric detector with electrospray ionization Jet Stream ion source (Agilent Technologies, USA). Analytes were separated by a Zorbax SB-Phenyl rapid resolution column (4.6 × 150 mm, 3.5 μm, 80 Å , Agilent Technologies) protected by a Zorbax SB-Phenyl precolumn (4.6 × 12.5 mm, 5.0 μm, Agilent Technologies). Spectrophotometric detection was performed at various wavelengths depending on the analyzed dye (280, 400, 450, 480, 500, 550, 580 or 600 nm). Mass spectrometric data were acquired in dynamic multiple reaction monitoring (dMRM) modes of negative and positive ions. Parameters of the method were described by Lech [1] . The analyses were controlled and processed by a MassHunter Workstation software (Agilent Technologies, USA).

Declaration of Competing Interest
The author declares that she has no known competing financial interests or personal relationships which have, or could be perceived to have, influenced the work reported in this article.