Floating resistivity detector for microchip electrophoresis.
A newly developed conductivity detector, the floating resistivity detector (FRD), for microchip electrophoresis was introduced in this work. The detector design permits decoupling of the detection circuit from the high separation voltage without compromising separation efficiency. This greatly simplifies the integration of microchip electrophoresis systems. Its method of detection relies on platinum electrodes being dipped in two buffer-filled branched detection probe reservoirs on the microchip device. In this way, analytes passing through the detection window will not pass through and subsequently adsorb onto the electrodes, alleviating problems of electrode fouling due to analyte contamination and surface reactions. A customized microchip design was proposed and optimized stepwise for the new FRD system. Each branched detection probe was determined to be 4.50 mm long with a 0.075 mm detection window gap between them. The distance between the detection window and buffer waste reservoir was determined to be 1.50 mm. The optimized microchip design was subsequently used in the analysis of four groups of analytes - inorganic cations, amino acids, aminoglycosides antibiotics, and biomarkers. Based on the preliminary results obtained, the detection limits were in the range of 0.4-0.7 mg/L for the inorganic cations and 1.5-15 mg/L for the amino compounds.
Tay
Elaine Teng Teng
ET
Department of Chemistry, National University of Singapore, Singapore, Republic of Singapore.
Law
Wai Siang
WS
Sim
Steven Poh Chuen
SP
Feng
Huatao
H
Zhao
Jian Hong
JH
Li
Sam Fong Yau
SF
D000596:Amino Acids / Q000032:analysis; D000900:Anti-Bacterial Agents / Q000032:analysis; D015317:Biogenic Polyamines / Q000032:analysis; D002412:Cations; D046209:Electrophoresis, Microchip / Q000295:instrumentation*; D004867:Equipment Design; D008670:Metals / Q000032:analysis; D013056:Spectrophotometry, Ultraviolet
D000596:Amino Acids; D000900:Anti-Bacterial Agents; D015317:Biogenic Polyamines; D002412:Cations; D008670:Metals