Atomic level analysis of biomolecules by a scanning atom probe

摘要

The biomolecules methionine, cystine, glycine, and leucine were analyzed by a scanning atom probe. Single-walled carbon nanotubes grown by the high-pressure carbon monoxide process were used to prepare a small ball of tangled carbon nanotubes, which was then attached to a tungsten tip using silver paste. A prepared tip was dipped into a sample solution of each biomolecule. Various ions, such as methyl, amino and carboxyl groups, were detected and indicated the binding states of the molecules. Cysteine, cystine, and methionine are the only amino acids that contain sulfur, and were analyzed to investigate the binding state of the sulfur atom. The number of atoms in each of the major mass peaks were counted and compared with the number known to be in the molecule. The results indicate that the scanning atom probe analysis is reasonably quantitative.