1. Dual-wavelength light-emitting diode-based ultraviolet absorption detector for nano-flow capillary liquid chromatography
- Author
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Milton L. Lee, Xiaofeng Xie, H. Dennis Tolley, Thy Truong, Luke T. Tolley, and Paul B. Farnsworth
- Subjects
Analyte ,Orders of magnitude (temperature) ,Capillary action ,Analytical chemistry ,02 engineering and technology ,01 natural sciences ,Biochemistry ,Chemistry Techniques, Analytical ,Analytical Chemistry ,law.invention ,Limit of Detection ,law ,Detection limit ,Chromatography ,Chemistry ,010401 analytical chemistry ,Organic Chemistry ,Detector ,General Medicine ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Volumetric flow rate ,Wavelength ,Indicators and Reagents ,Spectrophotometry, Ultraviolet ,0210 nano-technology ,Chromatography, Liquid ,Light-emitting diode - Abstract
The design of a miniaturized LED-based UV-absorption detector was significantly improved for on-column nanoflow LC. The detector measures approximately 27mm×24mm×10mm and weighs only 30g. Detection limits down to the nanomolar range and linearity across 3 orders of magnitude were obtained using sodium anthraquinone-2-sulfonate as a test analyte. Using two miniaturized detectors, a dual-detector system was assembled containing 255nm and 275nm LEDs with only 216nL volume between the detectors A 100μm slit was used for on-column detection with a 150μm i.d. packed capillary column. Chromatographic separation of a phenol mixture was demonstrated using the dual-detector system, with each detector producing a unique chromatogram. Less than 6% variation in the ratios of absorbances measured at the two wavelengths for specific analytes was obtained across 3 orders of magnitude concentration, which demonstrates the potential of using absorption ratio measurements for target analyte detection. The dual-detector system was used for simple, but accurate, mobile phase flow rate measurement at the exit of the column. With a flow rate range from 200 to 2000nL/min, less than 3% variation was observed.
- Published
- 2017