Office Chromatography: Miniaturized All-in-One Open-Source System for Planar Chromatography.

Current high-performance-thin-layer-chromatography instrumentation is offline and stepwise automated. However, moderate miniaturization offers many advantages and together with the transfer of modern print and media technologies to the field of chromatography (office chromatography) it opens up new avenues. This is demonstrated in an all-in-one open-source system developed for planar chromatography and especially for ultrathin-layer chromatography. Using an InkShield board to control a thermal inkjet cartridge, picoliter drops were printed at a resolution of 96 dpi on the adsorbent layer. Using Marlin, a popular firmware in 3D printing, Cartesian movement of the print head was made possible for full control of the printing process. Open-source software was developed to control the device in each operation step. Sample solutions and mobile phase were inkjet-printed, exemplarily shown for the analysis of dye- or paraben-mixture solutions. Light-emitting diodes (LEDs) were investigated for documentation. For example, deep UV LEDs gave access to 254 nm light, and RGB LEDs gave access to the visible-light range. Calibration functions with correlation coefficients superior to 0.999 were obtained by videodensitometry. The developed modular open-source hardware was compact (26 × 31 × 26 cm), light (<3 kg), and affordable (€810). For the given analyses, the footprint of current instrumentation needed was miniaturized by a factor of 9. The highly reduced material design complies with green chemistry and lean laboratory. The design and instruction to reproduce the all-in-one open-source system were made freely available at https://github.com/OfficeChromatography . It is intended to boost progress and understanding by the nature of do it yourself.