Researchers Miniaturize Mass Spectrometer with Carbon Nanotube Coating

A carbon nanotube-coated paper triangle placed on an ionization source charged by a small battery is held in front of a mass spectrometer.

A team of researchers from Purdue University and the Indian Institute of Technology – Madras (IIT-M) led by R. Graham Cooks and Thalappil Pradeep have developed a carbon nanotube coating to shrink mass spectrometers. The researchers discovered that a carbon nanotube-coated paper used to collect a sample was not only able to reduce the required voltage by a 1000 times but also produced a sharper signal, allowing capture of more delicate molecules on the mass spectrometer. These experimental findings indicates the potential for reduction in battery size and cost of experiments.

This new technique is developed on the basis of paper spray ionization technique. A nanotube-impregnated paper is placed on the mass spectrometer with a special attachment, and an electrical field is created by applying a small voltage. The nanotubes on the surface of the paper generate a very strong electric field that allows signal detection for analyzing the sample. In fact, one volt over a few nanometers creates an electric field equivalent to 10 million volts over a centimeter.

In isolating these nanotubes to prevent bundling and to ensure individual nanotubes project out of the paper, the carbon nanotubes were found to work well – not only can they be dispersed in water but also can be applied on suitable substrates. Another advantage of these carbon nanotubes is the elimination of background noise during analysis, resulting in a sharp and clear signal of the sample.

In addition to the most promising feature of miniaturizing mass spectrometers, the researchers have also fine-tuned this technique to be employed in a wide range of applications such as medical testing, explosives detection and food safety. The research has been published in the journal Angewandte Chemie.