Atmospheric Pressure Ionisation

Atmospheric Pressure Ionisation designates mass spectrometry ionisation techniques operating at atmospheric pressure, including electrospray ionisation and atmospheric pressure chemical ionisation, enabling coupling of liquid chromatography with mass spectrometric detection for pharmaceutical analysis of small molecules, peptides, proteins, and metabolites.

The pharmaceutical industry employs atmospheric pressure ionisation mass spectrometry extensively throughout drug discovery, development, and quality control. Electrospray ionisation generates multiply charged ions enabling analysis of large biomolecules including intact antibodies and protein complexes. Atmospheric pressure chemical ionisation provides complementary ionisation for less polar compounds. LC-MS/MS using these techniques delivers highly sensitive, selective quantitative analysis for pharmacokinetic studies, metabolite identification, impurity profiling, and biomarker measurement. Method development optimises ionisation conditions maximising analytical performance. As analytical demands increase across pharmaceutical development, atmospheric pressure ionisation mass spectrometry continues providing essential quantitative and qualitative measurement capabilities.