Picomolar detection limits for glyphosate by two-dimensional column-coupled isotachophoresis/capillary zone electrophoresis-mass spectrometry.
Hannes Georg GrafBenjamin Maximilian RudischLukas UdeLinda MüllerCarolin HuhnPublished in: Journal of separation science (2022)
Capillary electrophoresis-mass spectrometry often lacks sufficient limits of detection for trace substances in the environment due to its low loadability. To overcome this problem, we conducted a feasibility study for column-coupling isotachophoresis to capillary electrophoresis-mass spectrometry. The first dimension isotachophoresis preconcentrated the analytes. The column-coupling of both dimensions was achieved by a hybrid capillary microfluidic chip setup. Reliable analyte transfer by voltage switching was enabled by an in-chip capacitively coupled contactless conductivity detector placed around the channel of the common section between two T-shaped crossings in the chip connecting both dimensions. This eliminated the need to calculate the moment of analyte transfer. A commercial capillary electrophoresis-mass spectrometry instrument with easily installable adaptations operated the setup. Prior to coupling isotachophoresis with capillary zone electrophoresis-mass spectrometry, both dimensions were optimized individually by simulations and verified experimentally. Both dimensions were able to stack/separate all degradation products of glyphosate, the most important herbicide applied worldwide. The first dimension isotachophoresis also removed phosphate, which is a critical matrix component in many environmental samples. Enrichment and separation of glyphosate and its main degradation product aminomethylphosphonic acid by the two-dimensional setup provided an excellent limit of detection of 150 pM (25 ng/L) for glyphosate.
Keyphrases
- capillary electrophoresis
- mass spectrometry
- liquid chromatography
- tandem mass spectrometry
- high throughput
- circulating tumor cells
- gas chromatography
- high performance liquid chromatography
- label free
- high resolution
- loop mediated isothermal amplification
- simultaneous determination
- solid phase extraction
- room temperature
- heavy metals
- real time pcr
- risk assessment
- drinking water
- electron transfer
- particulate matter
- climate change
- human health
- quantum dots
- polycyclic aromatic hydrocarbons