Red/Black Phosphorus and Phosphorene as Matrices and Calibrants in MALDI TOF Mass Spectrometry of Biomolecules Govinda Mandal (Presenter) Masaryk University, Czech Republic >> POSTER (PDF) Presenter Bio: My name is Govinda Mandal. I am a citizen of Nepal which is Asian developing country. I have completed B.Sc. from Tribhuvan University, Nepal and M. Sc. Pharmaceutical chemistry from HNB Garhwal University, India. I have about 8 years work experience in Quality Control Department of Pharmaceutical Industries as Analyst/QC Manager (HOD). At present, I am pursuing PhD in chemistry at Masaryk University, Brno, Czech Republic.

Authors: Govinda Mandal, Petr Vanhara, Josef Havel
Masaryk University, Brno, Czech Republic

Red and black phosphorus (P), as well as phosphorene, a monolayer or several layers of black phosphorus-prepared by ultrasound-added exfoliation in N-methyl-2-pyrrolidone3, or phosphorene-diamond composites, were examined as matrices in matrix-assisted laser desorption-ionization (MALDI) time-of-flight mass spectrometry of metabolites, peptides or other small molecules in complex mixtures. Performance of P-based matrices in LDI as well as in MALDI was examined, and the formation of Pn clusters suitable for internal mass calibration of complex biological samples was evaluated. Here, we demonstrate enhanced ionization of bio-molecules in complex biological liquids on unusual P matrices.

Introduction

MALDI TOF mass spectrometry is a powerful and highly sensitive tool for detection and characterization of various biomolecules in complex biological samples, such as cell extracts or tissue extracellular fluids and plasma. This challenging analytical complexity, however, may result in low ionization of molecules and thus in their limited detection, identification or quantification. In this work, we focused on red or black phosphorus, phosphorene and phosphorene-diamond composites, as novel and unusual matrices suitable for MALDI TOF MS of complex biological samples.

Methods

Mass spectra were recorded either using MALDI-TOF Mass Spectrometer AXIMA CFR and/or an AXIMA Resonance QIT-TOF Mass Spectrometer, both from Kratos Analytical Ltd. (Manchester, UK), equipped with a nitrogen laser (337 nm), ion trap and reflectron. The laser energy was selected from 0 to 180 a.u. (arbitrary units). The repetition mode of experiments was performed at a frequency of 5 Hz and a pulse time width 10 nano seconds. Analyses were carried out in positive or negative ion modes. Mass spectra were accumulated using at least 1000 profiles.

Results

Formation of clusters derived from red or black P, or from phosphorene was demonstrated and Pn clusters were identified and characterized as documented previously. Defined Pn clusters can be used for either external or internal calibration. Here we demonstrated that matrices based on different P forms enhances ionization of biomolecules in complex samples while simultaneously offering precise internal calibration.

Conclusions & Discussion

Red and black phosphorus, phosphorene and phosphorene-diamond composites are effective and technically simple matrices for analysis of biomolecules in MALDI TOF MS. The best results are obtained using black phosphorus enriched CHCA as well as black phosphorus mediated SALDI. Simultaneously, they form precise and stable Pn clusters of phosphorus suitable as internal calibrant. Here we demonstrated novel properties of state-of the art Pn nanostructures suitable for ionization of biomolecules in complex biological samples.

References:

1. K. Sládková, J. Houška, J. Havel. Laser desorption ionization of red phosphorus clusters and their use for mass calibration in time-of-flight mass spectrometry. 2009; 23:3114-3118.

2. X. He, J. Ding, L. Yu, D. Hussain, Y. Feng. Black phosphorus-assisted laser desorption ionization mass spectrometry for the determination of low-molecular-weight compounds in biofluids. Anal. Bioanal. Chem. 2016; 408:6223-6233.

3. J.R. Brent, N. Savjani, E.A. Lewis, S.J. Haigh, D.J. Lewis. Production of few layer phosphorene by liquid exfoliation of black phosphorus. Chem. Commun. 2014; 50:13338-13341.

Acknowledgements:

This work was supported by Czech Health Research Council (project no. NV18-08-00299) and by Czech Science Foundation (project no. GA18-03823S).