FORMIC-ACID AMMONIUM FORMATE BUFFER SYSTEM FOR THERMOSPRAY LIQUID-CHROMATOGRAPHY MASS-SPECTROMETRY

A buffer system consisting of formic acid and ammonium formate was investigated as a strongly acidic mobile phase for thermospray liquid chromatography/mass spectrometry (TSP LC/MS). The behavior of the buffer was examined with regard to the relation between vaporizer control temperature and vaporizer tip temperature. Total intensity of solvent ions and sensitivity for target compounds as a function of vaporizer control temperature were also presented. The behavior of the formic acid-ammonium formate buffer was similar to that of an ammonium acetate aqueous solution, the usual mobile phase for TSP LC/MS. The applicability of the new buffer system to the compounds which required an acidic mobile phase was investigated. The new buffer system was found to reduce the peak tailing of amines and retain acids better than an ammonium acetate solution or an acetic acid-ammonium acetate buffer system. © 1990, The Japan Society for Analytical Chemistry. All rights reserved.