RATIONALE: Despite fast advances in ambient mass spectrometry imaging (MSI), the study of neutral and nonpolar compounds directly from biological matrices remains challenging. In this contribution, we explore the feasibility of laser ablation atmospheric pressure photoionization (LAAPPI) for MSI of phytochemicals in sage (Salvia officinalis) leaves. METHODS: Sage leaves were studied by LAAPPI-time-of-flight (TOF)-MSI without any sample preparation. Leaf mass spectra were also recorded with laser ablation electrospray ionization (LAESI) mass spectrometry and the spectra were compared with those obtained by LAAPPI. RESULTS: Direct probing of the plant tissue by LAAPPI efficiently produced ions from plant metabolites, including neutral and nonpolar terpenes that do not have polar functional groups, as well as oxygenated terpene derivatives. Monoterpenes and monoterpenoids could also be studied from sage by LAESI, but only LAAPPI was able to detect larger nonpolar compounds, such as sesquiterpenes and triterpenoid derivatives, from the leaf matrix. Alternative MSI methods for nonpolar compounds, such as desorption atmospheric pressure photoionization (DAPPI), do not achieve as good spatial resolution as LAAPPI (<400 µm). CONCLUSIONS: We show that MSI with LAAPPI is a useful tool for concurrently studying the distribution of polar and nonpolar compounds, such as phytochemicals, directly from complex biological samples, and it can provide information that is not available by other, established methods.
RATIONALE: Despite fast advances in ambient mass spectrometry imaging (MSI), the study of neutral and nonpolar compounds directly from biological matrices remains challenging. In this contribution, we explore the feasibility of laser ablation atmospheric pressure photoionization (LAAPPI) for MSI of phytochemicals in sage (Salvia officinalis) leaves. METHODS: Sage leaves were studied by LAAPPI-time-of-flight (TOF)-MSI without any sample preparation. Leaf mass spectra were also recorded with laser ablation electrospray ionization (LAESI) mass spectrometry and the spectra were compared with those obtained by LAAPPI. RESULTS: Direct probing of the plant tissue by LAAPPI efficiently produced ions from plant metabolites, including neutral and nonpolar terpenes that do not have polar functional groups, as well as oxygenated terpene derivatives. Monoterpenes and monoterpenoids could also be studied from sage by LAESI, but only LAAPPI was able to detect larger nonpolar compounds, such as sesquiterpenes and triterpenoid derivatives, from the leaf matrix. Alternative MSI methods for nonpolar compounds, such as desorption atmospheric pressure photoionization (DAPPI), do not achieve as good spatial resolution as LAAPPI (<400 µm). CONCLUSIONS: We show that MSI with LAAPPI is a useful tool for concurrently studying the distribution of polar and nonpolar compounds, such as phytochemicals, directly from complex biological samples, and it can provide information that is not available by other, established methods.
Authors: Juha-Pekka Hieta; Anu Vaikkinen; Samuli Auno; Heikki Räikkönen; Markus Haapala; Gianmario Scotti; Jaakko Kopra; Petteri Piepponen; Tiina J Kauppila Journal: J Am Soc Mass Spectrom Date: 2017-01-11 Impact factor: 3.109
Authors: Yeni P Yung; Raveendra Wickramasinghe; Anu Vaikkinen; Tiina J Kauppila; Igor V Veryovkin; Luke Hanley Journal: Anal Chem Date: 2017-07-05 Impact factor: 6.986
Authors: Fred A M G van Geenen; Maurice C R Franssen; Anton H M Schotman; Han Zuilhof; Michel W F Nielen Journal: Anal Chem Date: 2017-03-14 Impact factor: 6.986
Authors: Juha-Pekka Hieta; Nina Sipari; Heikki Räikkönen; Markku Keinänen; Risto Kostiainen Journal: J Am Soc Mass Spectrom Date: 2021-11-05 Impact factor: 3.109