Interfacing capillary gel microfluidic chips with infrared laser desorption mass spectrometry.
We report on the fabrication and performance of a gel microfluidic chip interfaced to laser desorption/ionization (LDI) mass spectrometry with a time-of-flight mass analyzer. The chip was fabricated from poly(methylmethacrylate) with a poly(dimethyl siloxane) cover. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis was performed in the channel of the microfluidic chip. After electrophoresis, the cover was removed and either the PDMS chip or the PMMA cover was mounted in a modified MALDI ion source for analysis. Ions were formed by irradiating the channel with 2.95 microm radiation from a pulsed optical parametric oscillator (OPO), which is coincident with IR absorption by N-H and O-H stretch of the gel components. No matrix was added. The microfluidic chip design allowed a decrease in the volume of material required for analysis over conventional gel slabs, thus enabling improvement in the detection limit to a pmol level, a three orders of magnitude improvement over previous studies in which desorption was achieved from an excised section of a conventional gel.
Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, USA.
Yichuan
Y
Xu
Mark W
MW
Little
Kermit K
KK
Murray
D020552:Comet Assay / Q000295:instrumentation* / Q000379:methods; D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods; D046209:Electrophoresis, Microchip / Q000295:instrumentation* / Q000379:methods; D007834:Lasers; D046210:Microfluidic Analytical Techniques / Q000295:instrumentation* / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000295:instrumentation* / Q000379:methods; D013055:Spectrophotometry, Infrared / Q000295:instrumentation* / Q000379:methods; D018511:Systems Integration