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Survey and assessmens of chemical substances in glass and porcelain colours

5 Chemical analyses

5.1 Test products
5.2 Methods of analysis
     5.2.1 GC/MS screening (extractable substances)
     5.2.2 X-ray
     5.2.3 Water content by Karl Fisher titration
     5.2.4 IR-screening
     5.2.5 Identification of azo pigments
5.3 Test results
     5.3.1 GC/MS screening (extractable substances)
     5.3.2 X-ray analyses
     5.3.3 Water content
5.4 Azo pigments
5.5 Summary of analyses

5.1 Test products

Table 5.1 shows the products included in the project.

Table 5.1 Test products selected for qualitative analysis

5.2 Methods of analysis

5.2.1 GC/MS screening (extractable substances)

Approximately 5 g of the product was taken and extracted with dichloor-methane added internal standard by using Soxhlet extraction for 16 hours. A part sample of the extract was taken and analysed directly as well as concentrated at combined gas chromatography and mass spectrometry (GC/MS) by scanning over a large mass area. The content is calculated compared to internal standards.

The analyses were carried out as genuine double specifications. The detection limit is 1-5mg/kg for components that are semi-quantified. The uncertainty is 10-20% RSD.

The analyses of 2-butanoneoxime were repeated in 2004 on four new versions of the products P1, P2, P10 and P11. The detection limit is 50 mg/kg. The uncertainty is 15% RSD.

5.2.2 X-ray

A part sample was examined using x-ray technique to discover the content of 40 elements. This analysis was outsourced.

The analyses were carried out as genuine double specifications. The detection limit is 10 mg/kg. The uncertainty of the analysis is 5-10% RSD.

5.2.3 Water content by Karl Fisher titration

The water content of the sample is determined by automatic titration using the Karl Fisher titration method (KF).

The analyses are made as genuine double specifications. The uncertainty of the analysis is 10% RSD.

5.2.4 IR-screening

A part sample was taken which was pressed into a potassium bromide tablet to be analysed by the FT-IR analysis to determine content of organic main parts by comparison with data library spectra.

The analyses were carried out as genuine double specifications. The analysis will not be reported separately. The result of the screenings has been used to support the result of the GC/MS screening.

5.2.5 Identification of azo pigments

A part sample test is refluxed with alkaline sodium dithionite and the azo pigment is transformed to arylamine by a reductive decomposition. An analysis for arylamines is made by use of high pressure chromatography (HPLC).

The detection limit is 5 mg/kg and the uncertainty is 10% RSD.

The analysis includes the following amines:

4-Aminodiphenyl, Benzidine, 4-Chloro-o-toluidin, 2-Naphthylamine, p-Chloraniline, 2,4'-Diaminoanisol, 4,4'-Diaminodiphenylmethan, 3,3'-Dichlorbenzidin, 3,3'-Dimethoxybenzidine, 3,3'-Dimethylbenzidine, 3,3'-Dimethyl-4,4'-diaminodiphenylmethane, p-Cresidine, 4,4'-Methylene-bis-(2-chloraniline), 4,4'-Oxydianiline, 4,4'-Thiodianiline, o-Toluidine, 2,4-Toluendiamine, 2,4,5-Trimethylaniline, o-Aminoazotoluene and 2-Amino-4-nitrotoluene.

The analysed amines are all covered by restrictions in the Statutory Order no. 755 of the Ministry of the Environment on prohibition of import, sale and use of certain pigments dated 15 August 2003. Azo pigments, which can emit these amines in concentrations above 30 ppm in the final products or in the coloured parts hereof, are not allowed to be used in textile or leather colours which may be in direct contact with human skin or mouth in for a longer period.

5.3 Test results

5.3.1 GC/MS screening (extractable substances)

The results from the GC/MS screening are shown below. The two results indicate the double specification. The substances were identified from the mass spectre by comparing with the mass specter in a data library. Specters, which represent the best match, are in each case assessed by "scientific judgment". In those cases where identification is not possible, the components are part of a group designation with a total sum. The detection limit is 1-5 mg/kg.

The DEPA requested that standards for each component were included, some were detected in the GC/MC screening and others were found at the survey.

These components are thus calculated compared to the equivalent external reference substances and marked by a ^ in the table. For all other organic components a semi quantative calculation has been made against internal standards. The detection limit for components compared to external standard is 1 mg/kg and the uncertainty is 10-15% RSD.

For a few components the content was so large that it was necessary to dilute the sample in order to calculate the content correctly. Those components are listed by
** in Table 5.2 and Table 5.3.

Because of findings in the survey DEPA wished to include the pigment diarylide (C.I. pigment yellow 12) as external standard. This component could not be obtained as standard why it was decided to analyse for a number of azo pigments in the two relevant samples of porcelain colours (yellow colours). The analysis for azo pigments is made by changing possible azo pigments into arylamines and then analyse for a total of 20 arylamines.

The results of the repeated analyses on the four products P1, P2, P10 and P11 are presented in table 5.4.

Table 5.2. Analysis results of extractable substances in glass and porcelain colours. The two results refer to the double specification. The results are in mg/kg. The detection limit is described above.

Click here to see Table 5.2

Table 5.3 Analysis results of extractable substances in glass and porcelain colours. The two results refer to the double specification. The results are in mg/kg. The detection limit is described above.

Click here to see Table 5.2

Table 5.4 Analysis results of repeated analyses of 2-butanoneoxime in four products. The two results refer to the double specification. The results are in mg/kg. The detection limit is described above.

^: betyder at komponenter er regnet overfor ekstern standard.

The new analyses in 2004 show concentrations of 2-butanonoxime in the range from 1.4 to 2.1%.

The substances in table 5.2, table 5.3 and table 5.4 are listed in Appendix A with CAS numbers.

5.3.2 X-ray analyses

Table 5.4 shows the results of the x-ray analyses. The elements not listed in the table were not detected at the analysis. The analysis is made by a single specification for reliability reasons. The detection limit is 10 mg/kg.

Table 5.4 The results from the x-ray analyses of glass and porcelain colours. The results are in mg/kg.

-: below the detection limit.

5.3.3 Water content

Table 5.5 and 5.6 show the results of water content analyses. The two values refer to the double specifications.

Table 5.5 Results of water analyses of glass and porcelain colours. The results are in %.

Table 5.6 Results of water analyses of glass and porcelain colours. The results are in %.

5.4 Azo pigments

Table 5.7 shows the results of the analysis of azo pigments. The analysis was only carried out in two yellow porcelain colours as agreed between COWI and DEPA.

Table 5.7 The results for arylmines of two selected glass and porcelain colours. The results are in mg/kg.

-: below the detection limit.

5.5 Summary of analyses

The screening analyses of constituent substances in glass and porcelain colours generally show that it is especially alcohols, glycols, ketones, esters, and simple hydrocarbons. Some of them are identified by name and others as substance groups. The levels in the different products vary from a few mg/kg to 150,000 mg/kg equivalent to 15%.

Methylpyrrolidone which is found in the highest concentration among these substances, are at a double specification measured to be between 8,000 and 150,000 mg/kg equivalent to 0.8-15.0% in the three products (P1, P2, P6, P10 and P11). 2-butanone oxime has been found in five products in concentrations between 1.4 and 2.9% (P11) and butoxyethanol in a concentration 2.4-2.5%.

Among the other substances it is a hydrocarbon composition (C6-C12) of

alifatic, alicyclic and aromatic hydrocarbons that are found in the highest concentration (17%). Furthermore phthalic acid anhydride (2.3-3.0%) is an example of another substance and group of substances that by double specification has been found in relatively high concentrations in one product. Toluene diisocyanate has been measured to 3.0-7.4% in one product.

Methoxy(propenyl)phenol (Eugenol) has been found in 2 products in concentrations between 21 and 26 mg/kg (0.0021 and 0.0026%).

Other substances have been found in concentrations from approx. 4 mg/kg (0.0004%) and up to approx. 5000 mg/kg (0,5%), most in the lower end. This also applies for the substances selected for toxicological assessment based on the chemical analyses. The substances are listed in Table 5.8.

Anthraquinone and 2-butanoneoxime were selected in the first place on the basis of the survey. 2-butanonoxime was at the first analyses found in concentrations in the range from 1.7 to 9.2%. The repeated analysis in 2004 has shown concentration levels from 1.4 to 2.1% for the four products P1, P2, P10 and P11.

Table 5.8 Selected substances for environmental and health assessment

Of metals lead, zinc, copper, cobalt and titanium have been found. Lead has been found in concentrations of 26 and 27 mg/kg equivalent to 0.0026 and 0.0027% in the products. In this way the concentration limits below 0.15% which requires special labelling of lead products to be used for chemical products as paint or varnish according to the Statutory Order no. 329 of the Ministry of the Environment dated 16 May 2002 on classification, packing, labelling, sale and storage of chemical substances and products.

The adjusted analytical result for lead in accordance with Danish Standard, DS/EN 71-3:1995 on safety requirements to toys and migration of particular materials is maximum 18.9 mg/kg (calculated based on the maximum measured concentration of 27 mg/kg). The adjusted analytical result is considerably below the standards requirements to the marginal value for migration of lead from toys of 90 mg/kg. The marginal value for migration of lead has been calculated based on the requirement of set out in the Statutory Order no. 1161 dated 12. December on safety requirements to toy.

Copper has been found in concentrations of up to 0.14%, cobalt in one product with a concentration of 0.056% and zinc also in one product in a concentration of 0.098%.

Two yellow porcelain colours have been examined for content of azo pigments with a negative result.

The analyses have thus determined approx. 50% (weight) of the content of all the products. Other constituent substance components are primarily binders and fillers.

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Version 1.0 July 2005, © Danish Environmental Protection Agency