Determination of polar organic pollutants in aqueous samples of former ammunition sites in lower saxony by means of HPLC/photodiode array detection (HPLC/PDA) and proton nuclear magnetic resonance spectroscopy (H-1-NMR)

Leachate, ground-, and surface water from former ammunition sites and areas which are known to be contaminated by nitroaromatic compounds in Lower Sax ony (Germany) were investigated in order to identify and quantify acidic ni troaromatic compounds (e.g., nitrobenzoic acids, amino-nitrobenzoic acids, nitrophenols, and nitrocresols). Acidic and neutral nitroaromatic compounds were enriched by solid-phase extraction (SPE) on a polystyrene-divinylbenz ene copolymer and routinely screened for acidic compounds by means of HPLC/ photodiode array detection (HPLC/PDA). Qualitative and quantitative results obtained in this way were corroborated by proton nuclear magnetic resonanc e spectroscopy (H-1-NMR). Validation data for the quantification procedure using this technique are given. The results show that all samples contamina ted with 2,4,6-trinitrotoluene (TNT) and related compounds are also contami nated by acidic nitroaromatic compounds (e.g., 2,4-dinitrobenzoic acid, 3,5 -dinitrophenol, and especially with 2-amino-4,6-dinitrobenzoic acid) in the mu g/L range. This current work shows that H-1-NMR allows the quantitative determination of proton-carrying analytes in mixtures after solid-phase ex traction down to the upper ng/L range after addition of an internal standar d to the SPE extract. This is even possible when reference compounds are no t commercially available.