Method of determining minute amounts of additives in polymers

A method of determining a previously unknown concentration of decabromodiphenylether in polystyrene by analyzing a plurality of samples of the polystyrene containing respective known concentrations of decabromodiphenylether, the method comprising:

• placing a pellet of one of the samples of polystyrene containing one of the known concentrations of decabromodiphenylether, as a flame retardant, on a silver face of a substrate;
• disposing a mixture of toluene and methanol, which dissolves polystyrene and decabromodiphenylether, on the pellet of polystyrene and between the pellet of polystyrene and the silver face of the substrate;
• maintaining the mixture of toluene and methanol between the silver face of the substrate and the pellet of polystyrene and dissolving some of the polystyrene and the decabromodiphenylether in the mixture of toluene and methanol;
• removing the pellet of polystyrene from the silver face of the substrate, leaving a residue of the polystyrene and the decabromodiphenylether that has been dissolved in the mixture of toluene and methanol on the silver face of the substrate;
• subjecting the residue of polystyrene and decabromodiphenylether that has been left on the silver face of the substrate to time-of-flight secondary ion mass spectrometry and correlating results of the time-of-flight secondary mass spectrometry with the known concentration of the decabromodiphenylether in the polystyrene of the one of the samples of polystyrene that has been analyzed;
• and
• repeating the foregoing steps for each of the samples of polystyrene with known concentrations of decabromodiphenylether and producing a relationship between the results of the time-of-flight secondary ion mass spectrometry for the samples of polystyrene and concentrations of decabromodiphenylether in the samples of polystyrene with the known concentrations, for determination of the previously unknown concentration of decabromodiphenylether in polystyrene.

A method of determining a previously unknown concentration of decabromodiphenylether in polypropylene by analyzing a plurality of samples of the polystyrene containing respective known concentrations of decabromodiphenylether, the method comprising:

• placing a pellet of one of the samples of polypropylene containing one of the known concentrations of decabromodiphenylether, as a flame retardant, on a silver face of a substrate;
• disposing toluene, which dissolves decabromodiphenylether, on the pellet of polypropylene and between the pellet of polypropylene and the silver face of the substrate;
• maintaining the toluene between the silver face of the substrate and the pellet of polypropylene and dissolving some of the decabromodiphenylether in the toluene;
• removing the pellet of polypropylene from the silver face of the substrate, leaving a residue of the decabromodiphenylether that has been dissolved in the toluene on the silver face of the substrate;
• subjecting the residue of decabromodiphenylether that has been left on the silver face of the substrate to time-of-flight secondary ion mass spectrometry and correlating results of the time-of-flight secondary mass spectrometry with the known concentration of the decabromodiphenylether in the polypropylene of the one of the samples of polystyrene that has been analyzed;
• and
• repeating the foregoing steps for each of the samples of polypropylene with known concentrations of decabromodiphenylether and producing a relationship between the results of the time-of-flight secondary ion mass spectrometry for the samples of polypropylene and concentrations of decabromodiphenylether in the samples of polypropylene with the known concentrations, for determination of the previously unknown concentration of decabromodiphenylether in polypropylene.