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Survey of chemical substances in textile colorants

3 Results

• 3.1 Qualitative determination of metals (X-ray)
• 3.2 Qualitative determination of volatile and semi-volatile compounds (GC/MS screening)
• 3.3 Quantitative determination of metals (ICP)
• 3.4 Quantitative determination of azo dyes
• 3.5 Quantitative determination of volatile and semi-volatile compounds (GC/MS screening)

3.1 Qualitative determination of metals (X-ray)

The results of the X-ray analyses are given in table 1. The analyses solely include metals with mass from element 19 (potassium). The metals not included in the table could not be determined at the analysis. All results are given with a number of + corresponding to the determined amount of metal in the product:

+ trace amounts (more than 5-10 mg/kg)
++ minor amounts
+++ moderate amounts
++++ large amounts.

Table 2 Results of the X-ray analyses. The results are given with a number of + for the amount of determined metal.

Previously metals such as cadmium, chromium, and lead could occur in colour products. Cadmium and chromium were not determined in the analyses and lead was only determined in one product.

The determined titanium in two products could e.g. be due to a content of titan dioxide applied as white pigment and filler. This also applies to calcium, which could be attributed to a content of calcium carbonate equally used as filler or white pigment.

Samples 1, 2, and 3 are all felt-tip pens. Sample 3 is analysed in one colour, whereas the results for samples 1 and 2 provide an average value for several colours. Subsequently during the project, samples 1 and 2 were analysed for more colours separately in order to identify a potential difference between the single colours. The colours that detected the largest content of cupper and lead were taken for further analysis at ICP (2.3).

The remaining products that contained copper, antimony, and lead were further analysed for these metals at ICP (2.3).

3.2 Qualitative determination of volatile and semi-volatile compounds (GC/MS screening)

The following pages provide the results of the semi-quantitative analyses for volatile and semi-volatile compounds. The number of crosses indicates the compound amount present in the product:

+ minor amounts
++ moderate amounts
+++ large amounts.

Table 3 Results of the headspace analyses. The results are semi-quantitative

Click here to see the table

The screenings for volatile solvents indicate that the products contain a large and varying number of compounds.

The content of volatile solvents is dominating i.e. alcohols (e.g. ethanol, butanol, ethylhexanol, and methyl-propanoles), ketones (e.g. acetone), ether (e.g. n-butylether), ester (e.g. ethyl acetate and butylpropanate) and aliphatic and aromatic hydrocarbons (e.g. C₈-C₉ alkanes, xylene, and methylstyrene). These compounds are present in most products and it is characteristic that they are also present in the water-based products. The compounds may either be added to the product to optimise the solubility of one or more additives or it may be introduced with the products raw material (e.g. as a solvent).

There are a number of other – and less volatile – compounds in some of the products in moderate/large amounts. E.g. phthalates (e.g. diethyl-phthalate), high-boiling aromatic and aliphatic hydrocarbon (e.g. cyclohexane- derivatives, C₁₆-C₁₇ aromates, and pentamethylheptane), alcoholes (e.g. phenoxy-ethanol), and 4-cyano-cyclohexene. The purpose of the presence of these compounds is varying and may be as surface active compounds preservative agents, dispersing agents etc.

3.3 Quantitative determination of metals (ICP)

The results of the specific metal analyses are given in table 4. All results are stated in mg/kg.

Table 4 Results of metal analyses. The results are stated in mg/kg.

LOD: Means the limit of detection
-: Means below the LOD
*: Means not analysed

As mentioned at the X-ray analysis the products have been analysed for antimony, cupper, and lead in products 1 and 2 that are both felt-tip pens. The analysis was performed on the dye with the largest amount of cupper and lead at the X-ray analysis. Thus the results in table 4 most likely provide the maximum content in the respective product series colour shades. The analysed dyes were dark blue for sample 1 and reddish brown for sample 2. Random colours have been analysed in the remaining products thus it has not been possible to establish whether the values represent the average values.

3.4 Quantitative determination of azo dyes

The analysis for azo dyes determines aromatic amines that have been segregated from the azo dyes. This analysis includes a total of 20 amines originating from the prohibited azo dyes.

The amines included in the analysis are as follows:

• 2,4-Diaminoanisol
• 2,4-Toluylenediamine
• o-Toluidine
• 4,4-Oxydianiline
• Benzidine
• p-Chloraniline
• p-Cresidine
• 4,4'-Methylendianiline
• 2-Naphthylamine
• 4,4-Thiodianiline
• 3,3-Dimethoxybenzidine
• 4-Chlor-o-toluidine
• 2,4,5-Trimethylaniline
• 3,3-Dimethylbenzidine (= o-Tolidin)
• 3,3-Dimethyl-4,4-diaminodiphenyl methane
• 4-Aminodiphenyl
• 3,3-Dichlorobenzidine
• 4,4-Methylene-bis(2-chlor-anilin)

The products 1, 4, 10, 11, and 12 were analysed for azo dyes. The selected products did not detect azo dyes above the limit of detection. The limit of detection is 30 mg/kg

3.5 Quantitative determination of volatile and semi-volatile compounds (GC/MS screening)

The following eight products were selected in co-operation with the Danish Environment Protection Agency for content analysis of extractable organic compounds (GC/MS screening). The below mentioned table provides the result of this analysis. The compounds marked with # are calculated to external standard (uncertainty 15-20% RSD), all other compounds are calculated to internal standard (uncertainty 50-200% RSD).

Table 5. Results of the GC/MS screening. The results are given in mg/kg.

- Means not determined
* Indicates the best possible identification
** Overestimated due to interference from other peaks
# Calculated to external standard

Several types of glycols were determined in the products as diisopropylene glycol, diethylene glycol, propylene glycol, 2-propanol, 2-(2-butoxyethoxy) ethanol, and 2-(2-ethoxyethoxy) ethanol. These glycols are typically used as solvents. Caprolactam is applicable as solvent for polymers.

Tributyl citrate can be used as softener in e.g. toner/pigments. Glycerine is used as solvent; however, it is also applicable as a surface-active agent, i.e. as a component able to retain water and thus prolonging the drying time. Hexamethylene tetramine is used as hardener in certain products.

Isobutane was determined in the two pop-up products.

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Version 1.0 July 2005, © Danish Environmental Protection Agency