The introduction of liquid samples into inductively coupled plasmas is predominantly done with pneumatic nebulizers. The task of such sample introduction systems is the conversion of liquid sample solutions into an aerosol. However, the aerosol produced in this process does not have ideal properties for use with ICPs, which is why spray chambers are used to optimize and filter the aerosol. As a result, the primary, polydisperse aerosol is converted into a tertiary aerosol with reduced polydispersity. Unfortunately, the use of spray chambers results in a loss of a significant amount of sample aerosol, leading to reduced sensitivity and decreased detection capability. Also, the risk of memory effects, necessitates substantial rinsing between individual measurements, thus increasing the analysis time. [1]

A sample introduction system designed to address some of the mentioned disadvantages is the drop-on-demand aerosol generator (DOD) developed by the Bings group in Mainz. This system is based on the thermal inkjet principle and thereby allows to eject discrete droplets through a dosing nozzle into the sample transfer line to the ICP. In addition to the direct generation of the aerosol, the DOD offers the possibility of frequency-based calibration. In previous studies, this principle of droplet generation using modified printer cartridges has already been demonstrated. [2,3]

The current focus of this work is the development and testing of a microchip-based system for aerosol generation, ideally designed as a flow-through system for hyphenation with separation systems. Recent results and remaining challenges will be presented and critically discussed.

[1] N.H. Bings, J. O. Orlandini von Niessen, J. N. Schaper, Spectrochim. Acta, Part B, 2014, 100, 14-37.

[2] J. O. Orlandini von Niessen, J. N. Schaper, J. H. Petersen, N. H. Bings, J. Anal. At. Spectrom., 2011, 26, 1781-1789.

[3] J. O. Orlandini von Niessen, J. N. Schaper, J. H. Petersen, N. H. Bings, J. Anal. At. Spectrom., 2012, 27, 1234-1244.