Results of the first and second British Mass Spectrometry Society interlaboratory studies on ambient mass spectrometry.

Rationale: As the popularity of ambient ionisation grows, so too does the importance of understanding its capabilities and limitations. The British Mass Spectrometry Society Special Interest Group on Ambient Ionisation has carried out two studies into the use of ambient ionisation, the results of which are presented here.

Methods: The first study (study 1) examined the detection and quantitation capabilities of ambient ionisation while the second examined repeatability and robustness. For study 1 participants were sent a range of samples including two calibration sample sets and asked to analyse them. For study 2, two samples containing the same eight-component mixture were provided (one in solvent, one in matrix); participants were asked to analyse these samples multiple times, over multiple days to allow assessment of repeatability.

Results: Study 1 showed that small, polar compounds were well detected by the participants while lower polarity compounds were less well detected. For many samples the introduction method appeared to be a significant factor in the observed spectra. The quantitation study gave good results but revealed significant variability. For study 2 the mean repeatabilities were 65% in solvent and 88% in matrix. The inclusion of an internal standard was shown to greatly improve repeatability.

Conclusions: Ambient ionisation is capable of ionising a wide range of compounds with good precision and excellent repeatability; however, in order to obtain such data care must be taken with the experimental design. The data can be significantly improved with a well-chosen internal standard.