Mass Spectrometric and Spectroscopic Studies of the Nutritional Supplement Chromium(III) Nicotinate

Abstract

Despite chromium nicotinate's popular use as a chromium nutritional supplement, the structure and composition of chromium nicotinate have only been poorly described. As solid chromium nicotinate is intractable, being insoluble or unstable in common solvents, studies on the solid have been limited, and studies of the solution from which the "compound" precipitates have additionally provided little additional data. The results of mass spectrometric and spectroscopic investigations designed to further elucidate the structure and composition of chromium nicotinate are described. The results demonstrated that the three common methods for producing "chromium nicotinate" all yield different compounds, all of which are polymers of Cr(III), oxygen-bound nicotinate, hydroxide, and water. Implications for interpreting results of nutritional studies of "chromium nicotinate" are discussed.

Aminopyridine complexes of Cr(III) basic carboxylates as potential polymer precursors: Synthesis, characterization, and crystal structure of [Cr3O(propionate)6(X-aminopyridine)3]+ (X = 3 or 4)

“…Basic chromium carboxylates have been examined previously by ESI MS [16,41,42]. Under ''soft'' low voltage conditions, the molecular ion is the most intense feature in the spectra, although minor features corresponding to loss of terminal ligands or exchange of terminal ligands with solvent molecules can be observed [13,37,38].…”

“…The voltage can be increased until the core [Cr 3 O(O 2 CR) 6 ] + cation gives rise to the most intense feature in the spectrum [41]. Fragmentation of the 3 ] + have previously revealed that the spectra were dominated by the signals from the molecular ions although signals from loss of one or two terminal ligands could also be observed [42].…”

Atomic spectrometry update. Clinical and biological materials, foods and beverages

“…Imaging of 20 mm sections of spinal cord using SIMS to show distribution of phospholipids, proteins and neuropeptides, was reported by Monroe et al 69 They suggested that the technique could be used to visualize changes in the chemical architecture induced by pain, anaesthesia, drugs etc. Structures within rat brain slices were likewise demonstrated by Becker et al 63 using LA-ICP-MS and in the cerebellum by Rhodes et al 123 using SRXRF. Popescu et al 124 looked at the distribution of Cu, Fe and Zn in brain slices from patients with Parkinson's disease.…”

Paramagnetic 19F NMR and electrospray ionization mass spectrometric studies of substituted pyridine complexes of chromium(III): Models for potential use of 19F NMR to probe Cr(III)–nucleotide interaction

“…Basic chromium carboxylates have been examined previously by ESI MS [23–25] Under “soft” low voltage conditions, the molecular ion is the most intense feature in the spectra, although minor features corresponding to loss of terminal ligands or exchange of terminal ligands with solvent molecules can be observed [23–25]. Because increasing the voltage at the first skimmer electrode results in more collisions of species of interest with solvent molecules within the ion source, higher voltages result in loss of more of the terminal ligands.…”