Publication: Novel LTCC-potentiometric microfluidic device for biparametric analysis of organic compounds carrying plastic antibodies as ionophores: Application to sulfamethoxazole and trimethoprim
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2011-12-15
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Tutors
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Elsevier
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Abstract
Monitoring organic environmental contaminants is of crucial importance to ensure public health. This requires simple, portable and robust devices to
carry out on-site analysis. For this purpose, a low-temperature co-fired ceramics (LTCC) microfluidic potentiometric device (LTCC/ POT) was developed
for the first time for an organic compound: sulfamethoxazole (SMX).
Sensory materials relied on newly designed plastic antibodies. Sol–gel, self-assembling monolayer and molecular-imprinting techniques were merged
for this purpose. Silica beads were amine-modified and linked to SMX via glutaraldehyde modification. Condensation polymerization was conducted
around SMX to fill the vacant spaces. SMX was removed after, leaving behind imprinted sites of complementary shape. The obtained particles were used
as ionophores in plasticized PVC membranes. The most suitable membrane composition was selected in steady-state assays. Its suitability to flow analysis
was verified in flow-injection studies with regular tubular electrodes.
The LTCC/ POT device integrated a bidimensional mixer, an embedded reference electrode based on Ag/AgCl and an Ag-based contact screen-printed
under a micromachined cavity of 600 m depth. The sensing membranes were deposited over this contact and acted as indicating electrodes. Under
optimum conditions, the SMX sensor displayed slopes of about −58.7 mV/decade in a range from 12.7 to 250 g/mL, providing a detection limit of 3.85
g/mL and a sampling throughput of 36 samples/h with a reagent consumption of 3.3 mL per sample.
The system was adjusted later to multiple analyte detection by including a second potentiomet-ric cell on the LTCC/ POT device. No additional
reference electrode was required. This concept was applied to Trimethoprim (TMP), always administered concomitantly with sulphonamide drugs, and
tested in fish-farming waters. The biparametric microanalyzer displayed Nernstian behaviour, with aver-age slopes −54.7 (SMX) and +57.8 (TMP) mV/
decade. To demonstrate the microanalyzer capabilities for real applications, it was successfully applied to single and simultaneous determination of SMX
and TMP in aquaculture waters.
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Keywords
Biparametric analysis, Ceramic tapes, Miniaturization, Potentiometry, Sulfamethoxazole, Trimethoprim
Bibliographic citation
Biosensors and Bioelectronics, (2011), 30(1), pp.: 197-203.