ISO 22195-5-2021 pdf free download – Textiles — Determination of index ingredient from coloured textile — Part 5: Lac.
This document specifies a test method which identifies the index ingredient chemical included incoloured fabric with lac.Lac can be applied to both natural fibre and man-made fibre.
2Normative references
The following documents are referred to in the text in such a way that some or all of their contentconstitutes requirements of this document. For dated references,only the edition cited applies. Forundated references, the latest edition of the referenced document(including any amendments) applies.
ISO 3696,Water for analytical laboratory use —Specification and test methods
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:- ISO online browsing platform: available at https://www.iso.org/obp
—IEC Electropedia: available at https://www.electropedia.org/
3.1
lac
scarlet resinous secretion of a number of species of lac insects, of which the most commonly cultivatedis Kerria lacca
Note 1 to entry: Lac is the common name of insect Kerria lacca.Thousands of lac insects colonize the branches ofthe host trees and secrete the resinous pigment. The coated branches of the host trees are cut and harvested asstick lac.This stick contains shellac.The spend of shellac extract is used for extraction of lac colorant.
3.2
coloured
expressing of colours to textiles by dyeing, printing or coating3.3
natural colourant
materials obtained from plants, wood, rocks, soil, insects or any other thing existing on earth withoutany chemical reaction adopted before colouring of textiles
4 Principle
The identification of natural colorant is very important in the scientific examination of the colouringsources of textiles, coloured print paintings, illuminated manuscripts and other works where naturalcolorants are used.Natural colourants are usually composed of several phyto chemicals.Each colourant has a distinctive chemical which acts as a chromophore and imparts specific colour. Colorants from natural sources can be identified by chemical structure of chromophoric chemical. This chromophoric chemical can be extracted from the dyed textile and identified by chromatography.
NOTE On the other hand, if the index component laccaic acid is detected through this test method, it cannot be said that it is necessarily stained with lac alone. However, based on this principle, applying this test method to unknown coloured fabrics or textiles is useful to provide a minimum amount of information that can be used to confirm whether the fabric is coloured using lac dye.
5 Reagents
Unless otherwise specified, use only reagents of recognized analytical grade.
5.1 Water, distilled or grade 3 in accordance with ISO 3696.
5.2 Acetonitrile, HPLC Grade.
5.3 Laccaic acid C, with a mass fraction of 99 %.
5.4 Dimethylformamide (DMF), analytical grade.
5.5? Trifluoroacetic? acid, HPLC Grade.
6 Apparatus
6.1 Analytical balance, resolution at 0,001 g.
6.2 Ultrasonic water bath, to be set up at (30 ± 2) °C.
6.3 Silica borate glass container, with a nominal volume of 50 ml.
6.4 Membrane filter, with 0,45 µm pore size.
6.5 Pipette, with a nominal volume of 20 ml.
6.6 Disposable syringe, with a nominal volume of 2 ml.
6.7 High performance liquid chromatograph (HPLC) with photo diode array (PDA) detector.
7 Procedure
7.1 Standard preparation
Stock solution of laccaic acid C (5.3) is prepared in acetonitrile (5.2) containing 1 000 mg/l.ISO 22195-5 pdf download.