APLI Source

Atmospheric pressure laser ionisation

The APLI option enables laser ionisation in combination with GC or LC. A nitrogen laser is used to obtain a dual step ionisation at 2*5 eV. This dual step ionisation delivers greatly enhanced selectivity, thus increasing the sensitivity in complex matrices. Typical applications are PAH analysis and analysis of complex fuels.

Ionization for MS-analysis of molecules containing aromatic rings or conjugated double-bonds

Atmospheric pressure laser ionization (APLI) can be considered a powerful alternative to APPI. In contrast to APPI, it comprises a two-step absorption process, thus realizing unseen selectivity. The high photon density delivered by the laser increases the sensitivity of this ionization technique by a factor of 10. This technique can be, effectively, used for all molecules containing conjugated double bonds or aromatic rings.

Using APLI for PAH determination, an S/N >100:1 can be achieved at a concentration of 1ppb.

APLI is based on photon ionisation via a two-step ionisation process. This two-step ionisation leads to increased selectivity since only compounds with an electronically excited state of a rather long lifetime can be ionised by APLI.

Compared to other ionisation techniques, APLI has two major advantages:
First, the spectra obtained with APLI are distinguished by a reduced base-line noise.
Second, the ionization efficiency for the various PAHs is generally orders of magnitude higher for APLI.