A new role for layered double hydroxides hybrid materials—uptake and delivery of small molecules into the gas phase

Abstract

Hydrotalcite (HT) intercalated tryptophan (trpH) and phenylalanine (pheH) hybrid materials have been prepared by the reconstruction method. Based on elemental analysis results, such materials were found to be prepared with the general formulas [Mg6Al2(OH)16](trp)1.42(OH + anions)0.58·4H2O and [Mg6Al2(OH)16](phe)1.26(OH + anions)0.74·4H2O, respectively. After characterization by powder X-ray diffraction and Fourier Transform Infrared Spectroscopy, the amino acid intercalated clays were used directly in Matrix Assisted Laser Desorption Ionization Mass Spectrometry experiments, where the clay was used as the matrix. The guests were detected in negative mode as [trpH–H]− at m/z 203 and as [pheH–H]− at m/z 164. From the mass spectrometry experiments no interference of ions from the clay was detected, meaning that such inorganic material is stable under the laser radiation and more important that it is adequate for use in such experiments. For the experiments using this particular approach we propose an alternative term—HALDI—standing for Host Assisted Laser Desorption Ionization mass spectrometry.