Spectrophotometric sensor system based on a liquid waveguide capillary cell for the determination of titanium: Application to natural waters, sunscreens and a lake sediment

An analytical procedure for the spectrophotometric determination of titanium at trace levels was developed. The procedure involves the use of a multi-pumping flow system (MPFS) coupled with a liquid waveguide capillary cell (LWCC) with 1.0 m path length, 550 μm i.d. and 250 μL internal volume, which enabled to enhance the sensitivity of the determination and thus avoid complex and time-consuming pre-concentration steps. The determination is based on the colorimetric reaction of titanium with chromotropic acid. The limit of detection (3σ) was 0.4 μg/L and a linear response up to 100 μg/L with a sample throughput of 46 h⁻¹, and a low reagent consumption/effluent production was achieved. The developed procedure was applied to natural waters, sunscreen formulations and one certified lake sediment sample.