Benzoic Acid, Ibuprofen and Mecoprop in Danish Groundwater Samples: A Retrospective Quantification StudyAuthor(s): Adam Smith*
The accepted practise for monitoring the quality of groundwater is target analysis of pre-selected chemicals. Although they may still exist, chemicals not on the target list are ignored in this targeted approach. In a prior Non-Target Screening (NTS) study, groundwater samples from catchments with a variety of land uses were analyzed by Solid Phase Extraction, Dispersive Liquid-Liquid Micro Extraction with Gas Chromatography Mass Spectrometry analysis (SPE-DLLME-GC-MS). Potential chemical markers for land use, including benzoic acid (a natural metabolite), ibuprofen (a pharmaceutical) and mecoprop (a pesticide), were identified but not in this study, the detected chemical markers in SPE groundwater extracts that had been frozen for three years were retrospectively analysed and a strategy for retrospective quantitative analysis was developed. The preserved extracts underwent derivatization to change carboxylic acid. Detected, most likely from the dominant coniferous forest on this site. A possible method for tracking land use markers is the combination of NTS analysis and retrospective quantification. The NTS’s lack of selectivity and storage effects make the technique difficult to implement method for preparing a sample. Derivatization and DLLME, two additional sample preparation procedures, were used in this study to increase the selectivity and sensitivity of the retrospective analysis.