Innovative Picoliter Droplet Printing Device Enables Cost-Efficient Multi-Elemental Printing for Micro Preparation

In a recent study published in Spectrochimica Acta Part B: Atomic Spectroscopy, a small and affordable picoliter droplet printing device capable of printing a wide range of elements for micro preparation applications was developed (1). By modifying the thermal ink cartridges, the researchers created a device that can conduct reliable deposition of 65 different elements. As a result, this new printing device introduces a cost-efficient solution for micro preparation that offers precise control over the deposition of multiple elements (1).

The researchers had to make several adjustments in designing this device to avoid challenges during the printing process. One modification that they made was adjusting the printing solutions to prevent nickel dissolution from the nozzle head (1). Doing so allowed the researchers to maintain a pH above 9, which prevented losing cations to the glass surfaces inside the nozzle head. Another modification that the researchers did was occasionally using additives such as tetramethylammonium hydroxide to help facilitate some challenging elements, with silicon being one specific example (1).

To evaluate their work, the researchers analyzed the volumes and masses of the deposited droplets. Using laboratory-scale measurements, they determined that the droplet volumes ranged from 142 to 184 picoliters, depending on the formulation (1). The delivered masses of the elements per droplet ranged from 0.98 to 11.9 picograms, with high reproducibility achieved (1).

The researchers used atomic force microscopy, confocal laser scanning microscopy, and optical microscopy to conduct further characterization of the printed deposits. The deposits were found to be mostly spherical, with an average diameter of approximately 14 μm and a height of approximately 2 μm (1).

The versatility of the picoliter droplet printing device allows for the micro preparation of solid compounds, facilitating the establishment of a library for grazing incidence X-ray diffraction analysis. As a demonstration, the researchers synthesized the MgAl2O4 spinel by printing the formulation and subsequent calcination (1). This innovative printing technology holds great promise for applications in recycling critical elements from pyrometallurgical slags and other fields where precise micro preparation is required.

Reference

(1) Hampel, S.; Sand, F.; Gonzalez, D. A. M.; Pepponi, G.; Helsch, G.; Deubener, J.; Schirmer, T.; Fittschen, A.; Fittschen, U. E. A. Chelate complexed multi-elemental printing performance of a small and cost efficient picoliter droplet printing device for micro preparation. Spectrochimica Acta Part B: At. Spectrosc. 2023, 206, 106716. DOI: 10.1016/j.sab.2023.106716