Analytical Sciences

Supercritical Water Decomposition of Polyethylene Samples for the Determination of Their Trace Cadmium Content

Osamu SATO,* Masanori KONNO,** Yoshito WAKUI,* Hideyuki MATSUNAGA,* and Masayuki SHIRAI*

*Research Center for Compact Chemical Process, National Institute of Advanced Industrial Science and Technology (AIST), 4-2-1, Nigatake, Miyagino, Sendai 983-8551, Japan
**Industrial Technology Institute, Miyagi Prefectural Government, 2-2, Akedohri, Izumi, Sendai 981-3206, Japan

A novel pretreatment method has been developed for determination of toxic metals in plastic materials by their decomposition under supercritical water conditions. Particularly, quantitative analysis of cadmium in polyethylene has been demonstrated using inductively coupled plasma atomic emission spectrometry combined with supercritical water treatment. All the cadmium in a polyethylene sample was obtained as an aqueous solution by the treatment with supercritical water containing 12.4% of hydrogen peroxide at 673 K. Although a complete recovery of the aqueous solution from the reactors has not yet been attained, we verified that the present method was effective and promising for quantitative analysis of trace amounts of hazardous metals in plastic materials.

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