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Updated: Jan 13, 2026

Synthesis of High Purity Nonsymmetric Dialkylphosphinic Acid Extractants
Published on: October 19, 2017
A McLafferty-Type Rearrangement in the Pentafluorobenzyl Ester Derivatives of Dialkyl Phosphates in GC-NICI-MS/MS: A
1Core Unit Proteomics, Institute of Toxicology, Hannover Medical School, 30623 Hannover, Germany.
Abstract:
Rearrangements such as the McLafferty rearrangement are common in mass spectrometry of positive ions, but rare in negative ions. The present article searched the literature for McLafferty rearrangements of negative ions formed by negative electrospray ionization (-ESI) or by negative-ion chemical ionization (NICI). McLafferty Rearrangements have been reported for negative ions formed by -ESI, yet not for anions formed by NICI in GC-MS and GC-MS/MS. This article reports for the first time a McLafferty Rearrangement of the collision-induced dissociation (CID) of precursor ions due to [M-PFB]- generated by NICI in the GC-MS/MS analysis of pentafluorobenzyl (PFB) esters and thioesters of diethyl phosphates (CH3CH2O)2PO2, diethyl thiophosphates (CH3CH2O)2PSO, and diethyl dithiophosphates (CH3CH2O)2PS2. Two specific product anions due to α,β-cleavages and formation of neutral losses of ethene and ethanol are formed. No McLafferty rearrangements were observed in the CID of 1-chloropropyl derivatives of these dialkyl organophosphates in the positive-ion chemical ionization (PICI) mode. McLafferty rearrangements of PFB esters of organophosphates have been observed in the EI mode. No McLafferty rearrangements were observed in the EI and NICI of diethyl fluoro phosphate, a representative of dialkyl fluoro phosphates. McLafferty rearrangements of negative ions seem to be more common than assumed so far.
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