Analysis of recycled thermoplasts from consumer electronics by laser-induced plasma spectroscopy

An experimental setup was established for on-line analysis of recycled thermoplasts from consumer electronics by laser-induced plasma spectroscopy (LIPS) along with the optimum experimental parameters. Via an experimental design, the optimum wavelength for plasma ignition and best parameters for a time-resolved detection, i.e. delay of the integration relative to the plasma ignition, gate width, and irradiance were determined. The employed echelle spectrograph allowed a fast multielement analysis due to the superior spectral coverage (200-780nm) and spectral resolution (λ/Δλ > 10,000 at 250 nm). Linear calibration plots were obtained by normalization to carbon as internal standard, the limits of detection are in the parts per million range and sufficient for the envisioned on-line application.