Preliminary recovery study of a commercial molecularly imprinted polymer for the extraction of glyphosate and AMPA in different environmental waters using MS

A commercial molecularly imprinted polymer (MIP) dedicated to glyphosate (GLY) and its main metabolite, aminomethylphosphonic acid (AMPA), was lately assessed as POCIS-like sampler on mineral water. The obtained results were encouraging with 111 and 122 mL day(-1) as sampling rates for GLYand AMPA, respectively. Therefore, before applying this passive sampler to environmental waters, the commercial phase was tested on different watermatrices as a solid-phase extraction (SPE) device. The SPE protocol was carried on 250 mg of MIP with the following three steps: conditioning by Milli-Q water, loading of the sample (15 mL), and elution of the analytes by 4 mL 0.1 M HCl that were evaporated to dryness and recovered in 15 mL of the suitable solvent for analysis. This protocol was first applied to mineral water spiked by GLY and AMPA at environmental concentration levels (25-750 ng L-1). Analyses were carried out by ultra-performance liquid chromatography hyphenated to tandem mass after derivatization of GLY and AMPA by 9-fluorenylmethylchloroformate. The linear correlation between concentrations measured with and without SPE on MIP was proved. Furthermore, other extractions showed that high concentrations of metal ion interferents (lead(II), cadmium(II), and zinc(II)) in groundwaters did not reduce SPE performance of the MIP. Then, concentration assays were undertaken and brought noteworthy results, such as the recovery of 80% GLY and AMPA from groundwater spiked at 10 ng L-1 and concentrated 100 times. For this purpose, ion exclusion chromatography hyphenated to mass was applied without previous derivatization of the analytes. The same concentration factor and analytical method were applied to 100 ng L-1 spiked sea water with recoveries of 96% for GLYand 121% for AMPA.