Interlaboratory Study on Volatiles Test for Food-Contacting Polystyrene Products

Using polystyrene, acrylonitrile-styrene resin and acrylonitrile-butadiene-styrene resin pellets as samples, an interlaboratory study was performed to evaluate the volatiles test method, based on the specifications described in the Japanese Food Sanitation Law for food-contacting polystyrene products. The study was conducted with the participation of twenty-one laboratories. Each laboratory quantified the contents of styrene, toluene, ethylbenzene, isopropylbenzene and propylbenzene in three test pellets using GC-FID, GC-MS or headspace-GC-FID. Statistical analysis revealed that the repeatability (RSDr) and reproducibility (RSDr) were 1.0-2.6 and 2.5-5.5% for the GC-FID method. The values of the performance parameters fulfilled the requirements (RSDr: 10%, RSDr: 25%), and the performance is sufficient for specifications testing. The RSDr and RSDr of results obtained using the GC-MS and HS-GC methods were 1.4-7.8 and 4.9-13%(GC-MS), and 2.0-2.6 and 3.3-6.9%(HS-GC-FID), respectively. The quantified levels were similar to those obtained with GC-FID. The study suggests that the GC-MS and HS-GC methods can be employed as alternative methods to the GC-FID method.