The concern about phthalates has dramatically risen as they are believed to threaten children’s health. The inspection of phthalates in toys is an indispensable task in the toy manufacturing industry. Fast and effective phthalates screening is a challenge for most toy manufacturers, importers and retailers.
People are increasingly concerned about the safety of human exposure to phthalates because it is believed that phthalates may be human cancer-causing agents, harming the liver and kidneys and possibly damaging the development of reproductive organs.
Phthalates are a group of chemical compounds used to render hard plastics flexible. They are mainly used as plasticizers in plastic fishing lures, nail polish, adhesives, caulk, paint pigments and some soft toys made of so-called "jelly rubber." Phthalates are used in modern electronic products such as MP3 players and personal computers.
There are a number of studies which highlight that phthalates can harm childhood development. Phthalate exposure in early childhood has been linked with altered hormone concentrations as well as increased allergies and eczema. Babies could be more at risk as their reproductive and immune systems are still developing (1). Some regulatory groups, such as the U.S. Consumer Product Safety Commission and the National Institute of Health’s Centre for the Evaluation of Risks to Human Reproduction are concerned that children who chew on PVC toys could ingest phthalates.
Some phthalates used in children's toys are restricted in the European Union, Japan and in the U.S. The use of DEHP, BBP and DBP are always restricted for use in toys. In 2004, the European Union enacted a permanent ban on the use of all phthalates in toys intended for children under the age of three. In the USA, three types of phthalates will be banned from children’s toys and child-care products starting in February 2009 while three other types of phthalates will be temporarily prohibited from child-care products and toys that can be placed in a child’s mouth. These regulations have prompted most toy retailers to switch to alternative substances thought to be safer (2).
It is difficult for consumers to ensure that the toys they buy are free of phthalate as phthalates are normally not listed on labels. For toy manufacturers and retailers, the effective detection of plasticizer content is a challenge. Traditional detection methods rely on gas chromatography (GC) with mass spectrometry or flame ionization detection. GC is unsuitable for the rapid measurement of multiple, sometimes undeclared, components in large numbers of samples although GC-MS and GC-FID are recognized as very accurate and sensitive (3).
Researchers based at Thermo Fisher Scientific have successfully developed a new FT-IR/ATR (Fourier transform infrared – attenuated total reflection) method to determine the content of phthalates in children’s toys. The experiments show that phthalates can be identified in plastic toys in a very short time (within 5 seconds).
Four toy samples were randomly collected and labelled A-D for analysis using an offline approach. The phthalates were then analyzed using an FT-IR spectrometer (Thermo Scientific Nicolet iS10 FT-IR spectrometer, Thermo Fisher Scientific) coupled with a diamond crystal ATR accessory (Smart iTR, Thermo Fisher Scientific). The diamond ATR element provides superior wide spectral range (4200-400 cm-1) and is particularly durable for hard solid samples. This allows the analysis of various toys with different hardness and shapes.
As shown in Figure 1, a toy can simply be placed on top of the diamond ATR. Contact between the tail and the diamond element is achieved with appropriate pressure applied on top of the tail. Then the spectral data were collected, processed and identified easily using the Thermo Scientific OMNIC software (Thermo Fisher Scientific). This entire process can be automated, making the analysis simple for use in any setting.
Comparison of the collected spectra with the libraries enables rapid identification of material contents in these toys. FT-IR ATR spectra of toys A–D were measured within 5 seconds each. The poly-vinyl chloride (PVC) specific C-Cl stretching band around 600-650 cm-1 is seen on all spectra, identifying that PVC material is used to make these toys. Further investigation of the spectra of toy A indicates that this toy contains PVC and considerable amounts of Bis(2-ethylhexyl) phthalate. The combined spectrum of PVC and Bis(2-ethylhexyl) phthalate (DEHP) overlays the spectrum of toy A, suggesting there is a large amount of DEHP in the toy. Under current legislation, Toy A is considered unsafe. A similar examination of toy B reveals toy B is primarily made of a PVC copolymer with ethylene vinyl acetate (EVA) and CITROFLEX. The latter material is a citric acid derivative plasticizer which is considered safe, and there is no spectral evidence for phthalates in toy B
Use of phthalates such as DEHP, BBP and DBP as plasticizers in PVC-based toys has caused considerable concerns about children’s health and therefore is restricted. An FT-IR ATR technique with diamond ATR and a library database offers a robust and simple sampling interface for rapid detection and identification of these phthalates. The detection limit for infrared will allow this method to be used as a preliminary screen for phthalates, since they are typically present in fairly high concentrations. The FT-IR/ATR technique with OMNIC software has proven itself many times as a powerful and fast raw materials screening tool for plastics manufacturers. The FT-IR/ATR package offers a fast solution to the detection and identification of PVC and phthalates in finished toys with a friendly user interface and precise result. The tools reported here can be used by non-specialists, retailers or importers to screen their inventory of toys and prevent harmful toys from reaching children’s hands.
While the limit of detection of this method is suitable for pre-screening of high concentration phthalates content in plastics, it should be noted that the concentration limit allowed by various regulations requires additional analytical investigation. However, several products on the market contain a much higher amount of phthalate-based plasticizers, which FT-IR can easily detect in seconds, resulting in an excellent pre-screening tool for custom laboratories or finished product manufacturers. l
1. Christine OKelly , November 04, 2008, Article of Advice, “Recent Phthalates Research Cause For Concern Among Parents”, available at: http://www.articlesofadvice.com/articles/225/1/Recent-Phthalates-Research-Cause-For-Concern-Among-Parents/Page1.html, accessed on November 19, 2008
2. Nicholas Casey and Melanie Trottman, October 23, 2008, The Wall Street Journal, “Toys Containing Banned Plastics Still on Market”.
3. Steve Down, September 01, 2008, Gas Chromatography, “Plasticizers do not cling to plastics films”, available at: http://www.separationsnow.com/coi/cda/detail.cda?id=19393&type=Feature&chId=3&page=1, accessed on November 18, 2008.