Generation and detection of gaseous W₁₂O₄₁^−· and other tungstate anions by laser desorption ionization mass spectrometry

Abstract

The presence of a peak centered near m/z 2862, observed for the first time for the caged dodecatungstate radical-anion, [W 12 The aqueous chemistry of tungsten and its oxocompounds is complex and elusive. Their characterization in aqueous solutions is complicated due to the occurrence of equilibrium aggregations and condensation reactions [4]. Undoubtedly, the aqueous chemistry of tungsten is challenging to all chemists interested in detecting inorganic ions. The methods employed for determination of tungstates include X-ray crystallography [9,10], and high performance liquid chromatography/ inductively coupled argon plasma (HPLC-ICP) mass spectrometry [11]. One of the problems in tungsten chemistry is that not many polyoxoanions crystallize without submitting themselves to considerable lattice disorder [4]. Moreover, the abundance of NMR-active nuclei in such complexes is low. Not only techniques such as Raman spectroscopy, optical spectrophotometry, and polarography can only be used for relatively simple mixtures, but also their capabilities to discriminate among different anionic species are rather limited. Besides, Raman spectroscopy requires comparatively high analyte concentrations. The application of potentiometric techniques to polytungstates is rather problematic since the method demands the attainment of an Address reprint requests to Professor A. B.

Reply to the Comment on: “Generation and Detection of Gaseous W12O41−• and Other Tungstate Anions by Laser Desorption Ionization Mass Spectrometry” by Julius Pavlov, Washington Braida, Adebayo Ogundipe, Gregory O’Connor, and Athula B. Attygalle, J. Am. Soc. Mass Spectrom. 2009, 20, 1782–1789.

“…As Lunk states, the literature on tungsten chemistry before our paper [4] does not report the observation of W 12 species from poorly soluble compounds such as CaWO 4 and PbWO 4 . However, these compounds have previously not been examined by such a sensitive technique as LDI-MS.…”

“…In fact, there have been only a few MS studies on tungsten compounds [5][6][7][8][9]. The relative intensity of [W 12 O 41 ] Ϫ• peak is about 10%-12% in our spectra recorded from deposits made from aqueous CaWO 4 and PbWO 4 , and 35% in the spectra of WO 2 . Clearly, mass spectrometry is the only technique capable of detecting such low levels of these ions in complex matrices.…”

Detection and imaging of chrome yellow (lead chromate) in latent prints, solid residues, and minerals by laser‐desorption/ionization mass spectrometry (LDI‐MS)

“…In fact, direct laser desorption/ionization coupled with time‐of‐flight mass spectrometry has been a very successful technique for the investigation of lead and chromium, as well as numerous other chemical elements . Laser desorption/ionization mass spectrometry (LDI‐MS) allows not only for elemental analysis but also for the chemical speciation of compounds …”

“…[19][20][21][22] Laser desorption/ionization mass spectrometry (LDI-MS) allows not only for elemental analysis but also for the chemical speciation of compounds. [11][12][13][14][15][16][17][18][19][20][23][24][25][26][27][28][29][30][31] Mass spectrometry imaging is a field of research that has received significant attention in recent years. [32] By this method, numerous biological samples have been imaged to reveal distribution patterns of a few chemical elements of biological significance found in cells and tissues.…”

Formation of molybdate ion clusters by phosphomolybdic anions under matrix‐assisted laser desorption/ionization conditions in the gas phase

“…In the recombination model, particles (neutrals, ions, atoms and aggregates) properly correlated in time, space and velocity recombine in the gas phase to give the most stable species. [8] The abundance distributions of ionic clusters obtained through MS can directly reflect their relative stabilities and usually relate to the geometric or electronic structures. [9] The higher intensities of specific clusters in mass spectra are referred to as magic numbers which may indicate the particularly stable cluster ions.…”