3D printed device for the automated preconcentration and determination of chromium (VI)

A 3D printed device for the fully automated disk-based solid-phase extraction (SPE) of Cr (VI) from watersamples has been fabricated. The compatibility of the use of organic solvents for analyte elution with 3D printedflow devices based on polymers fabricated using stereolithography has been evaluated. The developed methodologycomprises the complexation of Cr (VI) with 1, 5-diphenylcarbazide (DPC) in acidic medium and thesubsequent retention of the complex in a SBD-RPS disk contained within the 3D printed device. A multisyringeflow injection analysis system with online spectrophotometric detection has been used for the automation of themethod. The fabricated 3D printed device integrates the different components of the flow analysis manifold,including connectors and mixers, being a powerful approach towards the reproducible construction of highlyintegrated flow-based manifolds. The extracted Cr (VI)-DPC complex is eluted with a mixture of methanol- sulfuric acid and quantified at540 nm. The effect on the analytical signal and the optimization of variables were evaluated using multivariateand univariate techniques. A detection limit of 1 ng Cr (VI) and a linear working range of 3.2–600 ng Cr (VI)were obtained using a sample volume of 2 ml. The intra-day and inter-day RSDs were 4.8% (10 μg L−1, n=12)and 3.4% (n=5, different day with a different disk), respectively. The applicability of the fabricated 3D printeddevice has been proved by the determination of Cr (VI) in groundwater, surface water and leachates