The highs and lows of cocaine
Mass spectrometry is one of the most powerful methods for chemical analysis. The ability to image allows analysts to “see” molecules such as explosives or pharmaceuticals at surfaces. This is important for security applications, novel health care products and high technology manufacturing. Traditionally, surface mass spectrometry has been limited to vacuum techniques. Recent advances have enabled the chemical analysis of surfaces in the ambient environment allowing for vast improvements in analysis times as well as the ability to analyse in situ and volatile samples. Since the development of the first ambient ionisation source, desorption electrospray ionisation (DESI), in 2004, there has been rapid growth in these techniques.
Ambient mass spectrometry has shown great potential in many different fields including forensic analysis and the analysis of pharmaceutical and personal care products. Although there have been many publications exploring different applications, there have been few studies investigating the fundamental characteristics of the techniques. For the wider take-up of the method, especially by industry, there is a need to improve repeatability and develop the underpinning metrology. NPL has already contributed towards this for DESI, and we have now started to investigate and optimise the key parameters for another ambient technique, plasma assisted desorption ionisation (PADI). In this lecture recent developments will be highlighted and examples given of the effectiveness of these techniques for analysing different types of samples.