4. Conclusion

Chromatographic couplings using gas-phase ionization methods, such as APCI and APPI, enable a wide range of qualitative and quantitative analyses. However, these are not simple methods, due to the complexity of the mechanisms involved in the API source, whose gas-phase chemistry must be understood and mastered by the analyst if he or she is to understand the results and develop new analyses. Fundamental thermodynamic parameters such as proton affinities, electronic affinities and ionization energies must be taken into account for all molecules present at the same time in the API source: analytes, solvents, any additives, dopant, etc.

In the fourth and final part of this series of articles devoted to chromatographic-mass spectrometry couplings, we'll see that electrospray ionization can be used to connect many liquid-phase separative methods. However, the liquid-phase...