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Home > Magazine > Liquid Chromatography
Testing for BPA in Kid's ToysConcerns over bisphenol A requires monitoring of all polymer products.by Robert Troiano and William Goodman, PerkinElmer The BPA or bisphenol A has become well-known over the past year as concerns for its effect on human health and well-being have been raised. The concerns over BPA began with baby bottles and spread to include other types of bottles.
Testing for BPA in toys. | BPA is used in the production of two very common polymers—PVC and polycarbonate. PVC (polyvinyl chloride) is the primary component in many different products, including building materials, medical devices and children’s toys. BPA is used in PVC production as a polymerization inhibitor, and residual BPA may remain after the polymerization is complete. Polycarbonate is another commonly used plastic. It has desirable properties for both optical clarity and heat resistance. BPA is an important monomer in the production of the polycarbonate polymer, but not all of the BPA is consumed in the production and may leach out of the polymer. Recently, many applications of polycarbonate have been replaced with new copolymers, such as co-polyester, to eliminate BPA.
Figure 1. Chromatogram of water extract of a polymer toy dwarf sample.
Click to enlarge.
| As a result of the health concerns over human exposure to BPA, this molecule is now monitored in specific products, including children’s products. Simple and robust test methods are needed to determine the presence and amount of BPA in polymer materials.
Experimental
The study presented here includes extraction of BPA from a toy matrix and analysis with ultrahigh performance liquid chromatography (UHPLC). The extraction procedure used here is intended to simulate the contact routes through which children are likely to encounter BPA. Two different extraction techniques were used to analyze BPA in samples (30-g sample used for each extraction).
The first extraction method immersed the sample in 1 L of water, at 40 C for 24 hr (EN 14372). The second immersed the sample with 1-L HCl (0.07 M) at 37 C for 2 hr. Following extraction, the samples were analyzed with a PerkinElmer Flexar FX-10 UHPLC system including a PerkinElmer Series 200a fluorescence detector. The separation was performed on a Brownlee Validated C8 Column.
The BPA analyzed with the given LC conditions eluted at 5.43 min (see figure). The UHPLC system was calibrated across a range of 1- to 50-ppb (µg/L) BPA.
The limit of quantitation (LOQ) for BPA with the method presented here is 1 ppb. The signal to noise at the LOQ is approximately 10:1. The response across the calibration range fit a linear calibration with an r2 value of 0.9993. Blanks analyzed between standards and samples showed the system was free from any BPA contamination or carryover.
BPA in the extracts of the toy samples were quantified using the calibration curve generated during standard analysis.
The extraction procedure which heated the toy for 24 hr in water at 40 C extracted a significantly higher amount of BPA from the matrix than the extraction in acid. BPA was found in all three water extractions within the calibration range of the standard curve.
As health concerns over exposure to BPA are raised, its analysis in plastics is becoming increasingly important. The PerkinElmer Flexar FX-10 UHPLC system provides a sensitive and robust platform for these analyses.
Robert Troiano and William Goodman work at PerkinElmer, Waltham, Mass. For more information, call 800-762-4000 or visit ww.perkinelmer.com
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