Attenuated total internal reflectance infrared microspectroscopy as a detection technique for capillary electrophoresis.
A novel detector for capillary electrophoresis (CE) using single-bounce attenuated total internal reflectance (ATR) Fourier transform infrared (FT-IR) microspectroscopy is presented. The terminus of the CE capillary is placed approximately 1 microm from the internal reflectance crystal at the focus of an ATR infrared microscope. Using pressure driven flow injection, concentration and volume detection limits have been determined for 25- and 10-microm-i.d. silica capillaries. Upon injection of 820 pL of succinylcholine chloride in a 10-microm capillary, a concentration detection limit of approximately 0.5 parts per thousand (ppt), or 410 pg, is found. The injection volume detection limit using a 108 ppt solution is 2.0 pL (216 pg). Sample separations using a programmed series of pressure, voltage, and again pressure on 25-, 50-, and 75-microm-i.d. capillaries are shown. CE separations of citrate and nitrate, as well as succinylcholine chloride with sodium salicylate using acetone as a neutral marker, are demonstrated. Several advantages of this CE-FT-IR technique include: (1) minimization of postcolumn broadening as a result of a small detector volume; (2) the ability to signal average spectra of the same aliquot, thereby improving the signal-to-noise in a stopped-flow environment; and (3) simplicity of design.
Patterson
Brian M
BM
Molecular Microspectroscopy Laboratory, Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056, USA.
Danielson
Neil D
ND
Sommer
André J
AJ
D019075:Electrophoresis, Capillary / Q000295:instrumentation / Q000379:methods; D012680:Sensitivity and Specificity; D012822:Silicon Dioxide / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared / Q000295:instrumentation / Q000379:methods; D013390:Succinylcholine / Q000737:chemistry*; D013499:Surface Properties; D013997:Time Factors
D012822:Silicon Dioxide; D013390:Succinylcholine