Secondary processes in mass spectrometry of alkylmercury halides

Abstract

The sensitivity of the mass spectrometer towards RHgX alkylmercury halides in the electron impact technique was found to decrease in the order X = Cl > Br > I. The intense peaks corresponding to the more heavy halides registered in the mass spectra of RHgX were shown to arise owing to the secondary processes of halogen exchange occurring in the mass spectrometer. The non‐volatile bromine and iodine compounds adsorbed in some form on metallic surfaces of the ionization chamber (so‐called ‘memory effect’) could be the source of heavy halogens. These reactions are hampered in chemical ionization mass spectrometry under the sufficiently high pressure of the reagent gas (NH3).

Mass spectrometry of organomercurials

“…The agreement between GC-MS results and those obtained with a standard GC-electron-capture detection system and by neutron-activation was good-within 10% (35). Similarly, MeHgI conversion to MeHgCl occurred (34,161). As a result of these observations, the GC procedure was improved by the addition of MeHgCl to the samples or by repeated injections of microgram amounts of MeHg (162).…”

“…All attempts at fractionation have been unsuccessful, indicating that the bromides and iodides might not be impurities (34,35). The origin of these ions in the mass spectra of AlkHgCl has been investigated in detail under various experimental conditions (34). Some of the results indeed indicated that bromides and iodides were not present in the initial samples.…”

“…The mass spectra of alkylmercury chlorides showed very intense peaks of the corresponding alkylmercury bromides and iodides. All attempts at fractionation have been unsuccessful, indicating that the bromides and iodides might not be impurities (34,35). The origin of these ions in the mass spectra of AlkHgCl has been investigated in detail under various experimental conditions (34).…”

“…It was also found that the mass spectrum of Me,CCH,CH,HgCl recorded on a brand new mass spectrometer did not contain peaks due to heavier halogen derivatives. These peaks appeared after "washing" the mass spectrometer with iodine vapor (34). The abundances of iodo-containing ions relative to their chloro-containing analogues constantly decreased with time after that event, but never disappeared again.…”

A study of protonated molecules of crown ethers containing two thiourea segments by collision‐induced dissociation mass analysed ion kinetic energy spectrometry

“…This fragmentation pathway gives the most abundant product-ion peaks (100% relative abundance) by collision-induced fragmentation of MH+ ions. The compounds 3 [1,1], 8[2,2] and 12[3,3] with equal-length polyoxyethylene chains (m = n) decompose according to Reaction (1) to form the product ions 147+, 191+ and 235+, respectively, which are known from the EI mass spectra of crown ethers to be [M/2+ 11' ions. In the CID MIKE spectra of the MH+ ions of the compounds, the more-abundant product ions are formed from the MH+ ions by loss of the smaller neutral molecule (x = n if n < m).The second decomposition route of MH+ ions, the elimination of molecules with masses of 59u, 103u, 147 u, 191 u and 235 u is pronounced.…”