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

Abstract

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 122mLday-1 as sampling rates for GLY and AMPA, respectively. Therefore, before applying this passive sampler to environmental waters, the commercial phase was tested on different water matrices as a solid-phase extraction (SPE) device. The SPE protocol was carried on 250mg of MIP with the following three steps: conditioning by Milli-Q water, loading of the sample (15mL), and elution of the analytes by 4mL 0.1M HCl that were evaporated to dryness and recovered in 15mL of the suitable solvent for analysis. This protocol was first applied to mineral water spiked by GLY and AMPA at environmental concentration levels (25-750ngL-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 10ngL-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 100ngL-1 spiked sea water with recoveries of 96% for GLY and 121% for AMPA.