One-step 3D printed flow cells using single transparent material for flow injection spectrophotometry.

A very simple approach to fabricate flow-through cells for flow injection spectrophotometry is proposed. Flow cells are completely fused deposition modelling 3D printed by using coloured-transparent polylactic acid filament. Channels with 1.0 mm i.d. circular cross section and optical windows of 0.3-1.0 mm thickness are fabricated. Thin layers of the transparent material allow light transmitting with low attenuation, but coloured cell body can prevent stray light transmitting through. Transparent 3D printing filaments of different colours are compared and Grey-transparent (Grey-T) provides highest sensitivity for the determination of nitrite via Griess reaction. Flow cells of 10-50 mm pathlength have been fabricated by using the Grey-T filament. Effective pathlengths are estimated to be 83.9-96.2% of the physical pathlengths. The printing fabricated cells are used for flow injection analysis of nitrite, and linear correlation (R2 = 0.9991-0.9999) and limits of detection of 0.27, 0.087 and 0.045 μM for 10, 30 and 50 mm cells, are obtained. The 3D printed flow cells have acceptable chemical compatibility and signal stability.