Phthalates, or phthalate esters, are a popular choice for creating flexibility and softness in plastic and vinyl products. These plasticizers are uniformly distributed with the polymer material, but are not chemically bonded to it. However, some phthalates are suspected of being endocrine system disruptors and may have other toxic effects.
The U.S. government has banned three types of phthalates permanently: bis 2-ethylhexyl (DEHP), di-n-butyl (DBP), and butylbenzyl (BBP) phthalates. And it has banned three more on an interim basis –diisononyl (DINP), diisodecyl (DIDP), and di-n-octyl (DnOP) phthalates – for any concentration more than 0.1 percent in children’s toy and care products. Since plastic toys need to be monitored for these phthalates, the U.S. Consumer Products Safety Commission (CPSC) approved a test method involving extraction and analysis. The basic method describes a manual approach, consisting of dissolving the sample in tetrahydrofuran, precipitating PVC with hexane, filtering and diluting the solution with cyclohexane, and analyzing with GC/MS.
These steps are laborious and involve the handling of hazardous chemicals by the analyst.
GERSTEL scientists have developed a safer, automated method using the GERSTEL Multipurpose Sampler and MAESTRO analytical software that can still meet CPSC monitoring requirements and characterize phthalates in plastic products.
The scientists measured a standard containing the six banned phthalates, a certified reference material sample of phthalates, three unknown polyvinyl chloride (PVC) samples, and a toy plastic duck. All samples were prepared onto autosampler trays. Automated extraction, cleanup and introduction to GC/MS was performed with the MultiPurpose Sampler (MPS XL). Certified reference materials were taken through manual extraction steps, and results were compared to those from the same materials that were extracted automatically using the MAESTRO Prep Sequence. For other samples, the scientists performed automated extraction and preparation steps in accordance with the CPSC protocol including replicates to assess method reproducibility.
The results showed that manual liquid-liquid extraction processes could be easily transferred to a GERSTEL MPS XL and completely automated. The automated method also provided the same GC results as manual preparation: chromatographic results for all methods were virtually identical. In addition, SIM/scan MS analysis and chromatograms for the toy duck revealed several non-targeted plasticizers. Decreasing the amounts of sample by 50 percent (from 50 mg to 25 mg) to reduce consumption of hazardous chemicals appeared to have no effect on analysis results for phthalates.
For more details on this study, and to see the actual chromatographic results, read our application note: “Automated Extraction and GC/MS Determination of Phthalates in Consumer Products.” After reading the application note, feel free to contact us for a deeper conversation on how automation of product monitoring for potential toxins can free you from using hazardous chemicals and time-consuming manual steps.