Application Research Of Testing Methods Of High Concern Chemical Substances Based On New EU Toy Safety Directives

As economic and trade interactions between China and EU are getting closer in recent years, manufacturing industry in China has been deeply and widely affected by European regulations and directives as well as related harmonized standards of consumer products. As bulk commodity exported to EU, toys are also one of major non-food consumer products that are intensively supervised by EU. Meanwhile, EU has successively promulgated several directives concerning safety of toys since 2008, these new directives have not only lowered limits of original substances, but also brought many new substances into restriction, which poses grim challenges to current testing methods. Although current European harmonized standards have given testing methods for reference, some of them have drawbacks and still cause a lot of troubles in practical operations. Therefore, organotins, Cr(VI) and N-nitrosamines have been selected as three high-concern chemical substances based on notifications of European Rapid Alert System for Non-food Consumer Products in 2009~2013. The research of their testing methods is as follows:1. The cause of false positive phenomenon in migratable organotin testing based on gastric juice migration model has been found out by experiment. It is observed that triethylmethyltin was detected after coating materials with tin or tin-plating as base material treated according to organotin testing procedures specified in EN 71-3:2013+A1:2014. Furthermore, triethylmethyltin was also detected after conducting identical procedure to tin powder. Three assumptions were then proposed according to the testing procedure and related experiments were carried out for validation. It was found by experiments that the presence of triethylmethyltin had been caused by trace amount of methylating agents present in derivatization agent- sodium tetraethylborate. Meanwhile, the oringin of organotin was also explored and it turned out that the application of gastric juice migration model had been an important factor to cause the false positive phenomenon.2. Screening method of migratable Cr(VI) by inductively coupled plasma- atomic emission spectrometry and analytical method of Cr(VI) by ion chromatography – inductively coupled plasma mass spectrometry have been established based on EN 71-3:2013+A1:2014. Screening of migratable Cr(VI) is carried out simultaneously with testing of migration of other elements, limit of detection of screening method is 0.061 mg/kg, which satisfies Cr(VI) migration limit of Cat.III toy materials, more importantly, testing expense and time are exceedingly reduced; Meanwhile, drawbacks of migratable Cr(VI) testing method specified in the EU standard have been pointed out and a new testing method has been put forward, anion exchange column is used in the newly developed Cr(VI) analytical method, stressing on accurate determination of Cr(VI), influence of NH4NO3 concentration and pH values were studied extensively, limit of detection is capable to achieve 0.001 mg/kg, which satisfies the requirement of Cr(VI) migration limit of all three categories of toy materials. The experiments also indicate that Cr(VI) analytical method has good recoveries and precisions at different spike levels for various matrices.3. Analytical method of migratable N-nitrosamines and N-nitrosatable substances by high performance liquid chromatography – atmospheric pressure chemical ionization – tandem mass spectrometry has been established based on EN 71-12:2013. Mass spectrometric and chromatographic conditions of fourteen N-nitrosamines have been optimized and method detection limit has been lowered to 0.001 mg/kg after optimization, which satisfies migration limit of German regulations. Experiments show that the recoveries and standard deviations had been 88.0%~122.0% and 1.1%~13.9% respectively under 5, 50, 500 μg/kg spike levels. The developed method is implemented to the inspection of exit-entry spot-check samples, and it indicates that positive rate of balloon samples is up to 75%, showing balloons were samples of highest risk.The development of experiments and analytical methods stated above is favorable for better implementing EU toy safety directives and related harmonized standards and providing effective references for determination of high-concern chemical substances in toys, which is significant for preserving reputation of Chinese toy manufacturers and enhancing global competitiveness for toys exported from China.