HPLC-MS investigations of acidic contaminants in ammunition wastes using volatile ion-pairing reagents (VIP-LC-MS)

Abstract

In order to hyphenate ion pairing chromatography and MS detection we used several types of formates as volatile ion pairing reagents (IPRs) instead of common tetraalkylammonium salts, as these salts tend to precipitate in the ion source. The formates were prepared by mixing formic acid with the corresponding amine. Both tributyl- and trihexylammonium formate proved to be valuable IPRs for the separation of acidic compounds like nitrobenzoic acids, nitrobenzenesulfonic acids and nitrated phenols. Due to the weaker retention of the ion-pairs with trialkylammonium formates compared with tetraalkylammonium compounds, either less organic modifier or a higher concentration of the IPR had to be used. With negative atmospheric pressure chemical ionization mass spectrometry and electrospray ionization mass spectrometry it was possible to unambiguously identify several acidic oxidation products of 2,4,6-trinitrotoluene (TNT) in ammunition wastewater and soil extracts. 2-amino-4,6-dinitrobenzoic acid was often found to be the main metabolite of TNT in such water samples.

Strategies for the Analysis of Pharmaceutical Cocrystals Using HPLC with Charged Aerosol Detection

“…As previously [15][16][17]. Some examples also exist on the use of volatile amines (cationic) that can be used for the analysis of acidic compounds [13,14]. For the analysis of L-alanine with IPC, HFBA was used with the Atlantis T3 C18 column.…”

“…While both of these IPRs are very effective in retaining polar analytes, they are non-volatile and cannot be used with aerosol-based detectors. Several reports exist on the use of volatile IPRs in HPLC [13][14][15][16][17]. These volatile IPRs have mostly been used in mass spectrometry (MS) based detectors, but because they are volatile they can also be used with aerosol-based detectors.…”

Umweltanalytik mit Ionenchromatografie: Status quo und Zukunftsperspektiven

“…nichtacide Verbindungen wie Nitro-und Amino-Benzole bzw. -Toluole sowie Nitrobenzylalkohole werden ebenfalls detektiert (Schmidt et al 2004). Mit einem ähnlichen Verfahrensansatz können auch andere Sprengstoffe wie Pikrinsäure, Hexyl (Hexanitrodiphenylamin) sowie deren Metabolite (überwiegend Polynitrophenole) aufgespürt werden (Pamme et al 2002).…”

Analysis of dinitro- and amino-nitro-toluenesulfonic acids in groundwater by solid-phase extraction and liquid chromatography?mass spectrometry

“…However, ion-pairing HPLC with UV detection lacked the sensitivity and selectivity needed for trace analysis of the many dinitro-and amino-nitrotoluenesulfonic acids present in environmental water samples. Although ion-pairing HPLC hyphenated with mass spectrometric (MS) detection might provide good selectivity and sensitivity, the ion-pairing reagent selected must be compatible with MS detection [23]. Many ion-pairing agents, however, might contaminate the electrospray ionization (ESI) source and thus reduce the sensitivity of detection.…”