RT Journal Article
T1 Novel LTCC-potentiometric microfluidic device for biparametric analysis of organic compounds carrying plastic antibodies as ionophores: Application to sulfamethoxazole and trimethoprim
A1 Almeida, S.A.A.
A1 Arasa, E.
A1 Puyol, M.
A1 Martínez Cisneros, Cynthia Susana
A1 Montenegro, M.C.B.S.M.
A1 Sales, M.G.F.
AB Monitoring organic environmental contaminants is of crucial importance to ensure public health. This requires simple, portable and robust devices tocarry out on-site analysis. For this purpose, a low-temperature co-fired ceramics (LTCC) microfluidic potentiometric device (LTCC/ POT) was developedfor 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 mergedfor this purpose. Silica beads were amine-modified and linked to SMX via glutaraldehyde modification. Condensation polymerization was conductedaround SMX to fill the vacant spaces. SMX was removed after, leaving behind imprinted sites of complementary shape. The obtained particles were usedas ionophores in plasticized PVC membranes. The most suitable membrane composition was selected in steady-state assays. Its suitability to flow analysiswas 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-printedunder a micromachined cavity of 600   m depth. The sensing membranes were deposited over this contact and acted as indicating electrodes. Underoptimum 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 additionalreference electrode was required. This concept was applied to Trimethoprim (TMP), always administered concomitantly with sulphonamide drugs, andtested 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 SMXand TMP in aquaculture waters.
PB Elsevier
SN 0956-5663
YR 2011
FD 2011-12-15
LK https://hdl.handle.net/10016/31340
UL https://hdl.handle.net/10016/31340
LA eng
NO The authors acknowledge the financial support from FCT, Fundacão para a Ciência e Tecnologia/FEDER (project PTDC/AGR-AAM/68359/2006). Oneofus (Almeida SAA) is grateful to FCT for the PhD Grant (SFRH/BD/42509/2007).
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