Multipurpose Electrochemical Mass Spectrometry: A New Powerful Extension of Differential Electrochemical Mass Spectrometry

Abstract

In previously reported setups for differential electrochemical mass spectrometry (DEMS), the mass spectrometer was usable only for this application. The present publication describes a novel setup which overcomes this limitation using a dual inlet system. One inlet is connected to a vacuum recipient at which the electrochemical cell is attached when operating in the DEMS mode. The other one consists of a capillary inlet which can be used for various mass spectrometry applications. Without the necessity of shutting down the vacuum system, it is possible to switch modes by just opening and closing two valves. The present publication describes the connection to a thermogravimetric analyzer (TGA) via the capillary inlet. Using this setup, it is possible to detect thermal decomposition products as a function of temperature in addition to the determination of the weight loss. Additionally, the characteristic response time of the multipurpose electrochemical mass spectrometry (MPEMS) operating in the DEMS mode has been substantially improved compared to previous setups (20 to 50 ms in comparison to 200 to 500 ms). Thus, higher scan rates than the typical are now practical. Using sputtered electrodes, scan rates as high as can be applied. As indicated by the features described above, MPEMS is a versatile instrument with a wide range of applications not only in electrochemistry, but also in general analytical chemistry.