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Survey and health assesment of chemicals substances in sex toys 4 Screening analyses
The analysis programme for chemical substances will depend on whether the product is made of vinyl or rubber. Table 4.1 categorizes the products according to type and material. The categorisation is based on the product designation or an infrared spectroscopic analysis (styrene-ethene-butene-styrene (SEBS). For instance, some of the products, which were labelled jelly, were actually made of soft vinyl (PVC). Due to the lacking informative labelling the products were subjected to a Beilstein halogen test, where an annealed cupper wire is entered into the material where after it is led into a gas flame. If the sample holds chlorine the flame will turn green. Vinyl has a high content of chlorine and therefore a positive test will give important information about the presence of vinyl. Table 4.1 Analysed products acc. to function, material and number
As appears from the table the test was negative for the samples 4, 8, 13 and 16, and they were therefore screened for chlorine by a radiological analysis. Chlorine was detected in samples 4, 8 and 13, but not in 16. Based on the subsequent analyses it can be concluded that soft vinyl with a high content of plasticizers may give a negative Beilstein test result, even though the product contains chlorine. Further, it could be established that sample No. 16 mistakenly was assessed to be of hard vinyl because of the presence of cadmium, however, this has been found to be bound up with the yellow colour of the product. 4.1 Screening of element composition4.1.1 Method description of ICP/MSPrinciple All materials have been subjected to an element screening by ICP/MS after chemical digestion of the samples with concentrated nitric acid in quarts autoclaves with microwave induced heating. On basis of the screening quantitative analyses were made for elements, which alone are considered harmful (e.g. heavy metals), or are part of other harmful substances (e.g. organotin compounds, boron compounds or brominated substances). The element arsenic can only be identified in rubber products, as arsenic is drowned by the dominant chlorine peak from vinyl. The light elements such as oxygen, nitrogen, carbon and hydrogen cannot be detected by ICP/MS. Sample preparation Approx. 250 mg sample – precisely weighed out – was prepared with 5 ml 14 M HNO3 (subboiling quality) in a quartz autoclave by microwave induced heating. The resulting solution was strained and then diluted to 25 ml with demineralised water (Milli-Q Plus). Blank tests were prepared in the same way. Standards Standards and control tests were produced based on a Merck multiple element standard solution by diluting with 2.8 M HNO3. The internal standard mixture was produced from Perkin-Elmer single-element standards of Ge, Rh and Re by dilution with 0.14 M HNO3. Equipment Perkin-Elmer Sciex Elan 6100 DRC Plus ICP mass spectrometer with FIAS 400 flow injection system and auto sampler AS 93 Plus. Screening analysis With addition of germanium, rhodium and rhenium as internal standards ”on-line”, the prepared solutions were screened for trace elements by inductively coupled plasma - mass spectrometry (ICP-MS) using the expert programme TotalQuantIII, which based on an instrument response curve for elements from mass 6 (Li) to mass 238 (U) quantifies the content. The instrument response curve was updated by means of a multiple element standard listing 30 elements, which covers the whole mass spectre. The elements Br, C, Cl, F, I, N, O, P and S do not quantify because of the interferences. 4.2 Element screening resultsThe results are shown in Table 4.2. Table 4.2 Screening for content of chemical elements, samples 1-8 in mg/kg
*DL = detection limit Table 4.2 continued – Screening for content of chemical elements, samples 9-16 in mg/kg
*DL = detection limit Regarding content of lead and cadmium used as stabilisers for vinyl, the screening identified a cadmium content of 200 ppm in sample no. 16 (dildo in hard plastics). The high content was verified by a subsequent quantitative analysis (double determination), which showed a content of 218 ppm determined with a relative uncertainty of 1.4 %. According to "Statutory order from the Ministry of the Environment on prohibition of sale, import and production of cadmium-containing products" (Statutory order no. 1199 of 23/12/1992,), it is prohibited to sell products with such a high cadmium content in Denmark. Apart from identification of lead and cadmium the element screening has the purpose of detecting other compounds harmful to environment and health. It was established that samples 1 and 2 had a relatively high content of tin (maybe as trimethyltin chloride), in sample 11 the content was low. With the exception of samples 2 and 16, all samples contained considerable amounts of zinc, which, however, should have no negative health effect. It is a well-known fact that zincosid is part of most rubber recipes and of the vulcanization system, the biggest concentrations are therefore found in the samples 1, 5, 6, 7 and 14, which are all rubber based. 4.3 Analysis of chemical substances by GC/MSExcept for sample 16, vibrator in hard plastics, all products were GC/MS analysed for solvents and other chemical substances, light as heavy volatiles, either direct on headspace or on a dichloromethane extract (DCM). The DCM extracts were further used directly for quantitative determination of phthalates. 4.3.1 Method description:4.3.1.1 Test preparation and parameters for analysis of volatile organic substances (VOC) by headspace analysisA weighed-out sample amount (0.6-6 g) was put in a glass jar. A glass tube with adsorbent (tenax TA) was placed besides the sample. The Tenax filters were passively exposed for different time periods (30, 90, 120 and 180 minutes resp.). The Tenax tubes were subsequently analysed by thermal desorption combined with a Gas Chromatography/Mass Spectroscopy (ATD/GC/-MS in scan mode). The chemical substances were identified by comparing the respective mass spectres with spectres from the NIST Library. The amount of the detected substances was determined against the standards for toluene. The detection limit is estimated to 2-5 ng per component per tube and the relative uncertainty to 10-15%, relatively. The analyses were made on Perkin-Elmer TurboMass Spectrometer with Perkin Elmer ATD 400. 4.3.1.2 Test preparation and parameters for analysis of volatile substances in dichloromethane extractsA weighed-out sample amount (0.6-6 g) was extracted by dichloromethane added deuterium marked internal standards (benzene-d6, toluene-d8, p-xylene-d1, pyrene-d, and DEHP- d)4 by ultrasonic extraction and mechanical shaking. The extracts were analysed by a Gas Chromatography/Mass Spectroscopy GC/-MS in scan mode. The amount of the detected organic substances was determined against the internal standards and standards of the selected analytes. The amount of the detected phthalates was quantitatively determined against the respective phthalates standards - DEHP, DOP and DINP. The detection limit and relative uncertainty estimated to 0.2-1 µg/g and for other organic substances to 0.001% w/w in the product. Relative uncertainty 10%. Test equipment was a HP Gas Chromatography 5890 with HP Mass Spectroscopy 5972. 4.4 Analysis results4.4.1.1 Results of quantitative analysis of phthalatesSex toys in soft vinyl have been quantitatively analysed for content of plasticizers in the form of phthalates, as described above. The results can be seen from table 4.3. No other than the stated phthalates was detected in the screenings. Table 4.3 Survey of Phthalate content in sex toys in mg/gram
i.d. = not detected 4.4.2 Screening results of volatiles by headspace GC/MSA number of volatile organic substances were identified in the initial headspace analyses for organic substances by GC/MS of the 15 products, which have been alphabetically listed in Table 4.4 and 4.5. Results are stated in ng after degassing for 180 minutes at room temperature. Table 4.4 Survey of volatiles content in sex toys of soft vinyl (headspace) in ng/180 min. Table 4.5 Survey of volatiles content in rubber sex toys (1, 5, 6, 7 and 14) and thermoplastic rubber (10) (headspace) in ng/180 min.
4.4.3 Screening for chemical substances by dichloromethane extraction (DCM)Screening analyses by GC/MS were made of the more heavy volatiles in the 15 products through DCM extraction. The result of these analyses is listed alphabetically in Table 4.6 and 4.7. Table 4.6: Analyses results of heavy volatiles in the samples 1-7 in g/kg sample
Table 4.6: Analysis results of heavy volatiles in the samples 8-15 in g/kg sample
4.5 TLC-screeningsSex toys of rubber have been subjected to a thin-layer chromatography (TLC) screening for accelerators and antioxidants/antiozonants. 4.5.1 Applied TLC-methodsThe screening has been carried out according to BgVV chapter XXI (Kunststoffe im Lebensmittelverkehr, Empfehlungen des Bundesinstitutes für Risikobewertung) and ASTM D 3156-96: Standard Practice for Rubber - Chromatographic Analysis of Antidegradants (Antioxidants, Antiozonants and Stabilizers). Developing solvents The following developing liquids have been used:
Stationary phase Merck (article 1.11798) 20 x 20 cm Silica 60 F 254 with concentration zone 5 µl of solvents and standards are applied. After elution of the plates the developing solvent is evaporated in a fume cupboard before visual evaluation. Visualization The identification is made acc. to the Rf-value (the distance from origin to developing solvent front). The Rf value is thus between 0 and 1 in the chosen TLC systems. The evaluation of the results is made under UV light and by colour reactions (exposure to iodine vapours in closed chamber, colouring with Gibbs reagent or with a solution of copper sulphate). The preparation of reagents is described above under the mentioned standardised methods. 4.5.2 Examined products and applied reference substancesThe following samples are screened by TLC: 1, 5, 6, 7 and 14, as they according to the shop personnel or the labelling should be made of rubber. The labelling of the first four samples said that the product contained natural rubber (latex). The rubber quality of sample No. 14 was said to be food-grade quality (also used for gaskets for pressure cookers). For the TLC-screening the below listed reference substances were used. Further, the screening included rubber from rubber nipples (previously analysed by DTI for accelerators) and natural latex in food-grade quality. Table 4.4 Applied reference substances in TLC-screening.
4.5.3 Result of TLC-screeningsSamples nos. 5 and 6 are based on the same recipe and it also turned out that they were made by the same manufacturer, which was not evident when purchasing. ZDBC is used as sulphur accelerator (a substance which is able to cross-link the rubber molecules by sulphur bridges faster than with pure sulphur and at lower temperatures). This has been tested by developing solvents Nos. B and C and visualisation with copper sulphate. It is a known fact that ZDBC is used as accelerator for medical gloves of natural latex. ZDBC has been used in the co-analysed references (latex solution and rubber nipples). FDA (Food and Drug Administration, USA) allows ZDBC to be used in quantities up to 1.5 % in products with repeated food contact. Sample No. 7 shows indication of ZDBC presence in the recipe. Sample no. 1 does not give any uniform impression of the sulphur accelerator type. TLC screening of sample no. 14 indicates that more than one sulphur accelerator type has been used and there is positive indication of ZDMC/ZDEC. The latter is mostly known as antabuse in the form of disulfide. The TLC is not able to distinguish between disulfide and zinc salt in the dithiocarbamine acids, as they have the same Rf-value. The TLC-screening did not reveal any of the other reference substances used in the screening. This applies not only for 2-MBT and MBS but also BHT, which was positively detected by GC/MS on some of the products. 4.5.4 Verification of TLC-results by headspace GC/MSFor verification of TLC the tested samples have been analysed by headspace GC/MS method for an hour at 150°C, and at this temperature a partial decomposition of the dithiocarbamate-based accelerators will take place. The analysis detected carbon disulfide in samples 1, 5, 6 and 14, but none in sample 7. Dibutylamine was found in samples 5, 6 and 7. No. 6 further contained N,N-dibutylformamide. Carbon disulfide, dibutylamine and N,N-dibutylformamide are all known decomposition products from ZDBC. Dibutylamine and carbon disulfide were detected in the reference latex samples and di-isobutylamine and carbon disulfide in the rubber nipples. Degassing of diethylamine, dibutylamine, dimetyl ethyldiamine, dimetylpropylamine and triethyl phosphate was found in sample 7. No degassing of carbon sulfide. The degassing of triethyl phosphate was later found to originate from the inner foam core of the product. As the foam material may be polyurethane, degassing of amines may occur. Degassing of carbon sulphide, diethylamine and dimethylamine were found in sample 14. Also the TLC screening indicates that the associated thiuram accelerators (ZDMC/ZDEC or similar mono/disulfides of dithiocarbamine acid) have been applied.
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