The CARBOTEC FD emitter has been designed for FD applications that need an extra high sensitivity, such as the analysis of mixtures. Due to the extra strong Ion emission current, the CARBOTEC FD enables FD MS analyses with a sensitivity which exceeds that of the CARBOTEC Allround by a factor of 2.
Like the CARBOTEC ALLROUND, the CARBOTEC FD consists of a 10 µm tungsten wire and a pyrocarbon coating of carbon microneedles of approx. 120 µm in diameter. As with the CARBOTEC ALLROUND and the CARBOTEC Fl it can be used for several analyses in a row without loss of sensitivity. Clearing of the CARBOTEC FD between different analyses is carried out at an emitter heating current of 90 mA.
SENSITIVITY OF THE FD MS ANALYSIS
The special qualities of the CARBOTEC FD become evident when comparing the FD spectra of hexatriacontane (C36H74) recorded with the CARBOTEC ALLROUND (see spec. 3) and with the CARBOTEC FD (see spec. 4) under otherwise equal conditions. Both spectra were recorded at a potential difference of 12 kV as single scan spectra.
The intensity of the molecular ion in the FD spectrum of hexatriacontane (see spec. 4) is raised when using the CARBOTEC FD by a factor of 2 in comparison to the CARBOTEC Allround (see spec. 3). The reduction of the rate of fragmentation (e.g. formation of (M-2H) ions) is possible by lowering the potential difference and/or the sample amount deposited on the emitter. Because of the high ion signal intensity of the CARBOTEC FD, this results in a reduced rate of fragmentation at a still high level of sensitivity.