Fiber-Optic-Based Mode-Filtered Light Detection for Small-Volume Chemical Analysis

Abstract

and as shown in Figures 6 and 7, peak broadening increases with capacity factor. The key to reduced peak broadening is the use of thinner claddings. If an analyte is in the presence of a large interferent that has a RI different from the analyte, the cladding RI can be matched to that of the interferent so that the analyte will be selectively detected. Alternately, a short section of the annular column can be used as a detector only, in conjunction with capillary GC or microbore LC. Since the mode-filtered light detector is an optical detector, it can be used in hazardous areas where flame-based detectors are a concern.

Separation and determination synchronously by multichannel mode‐filtered light capillary electrochromatography

“…First, the most sensitive incidence angle of the laser beam was selected [4,[8][9][10], and then the instrument was run at a constant voltage of 8 kV for at least 8 h in the running buffer before sample introduction. Samples were electrokinetically injected into the annular column by applying a voltage of 8 kV for 15 s.…”

“…It is suitable for separation systems utilizing capillaries and has attracted much attention [5][6][7]. Mode-filtered light detection (MFLD) is a fiber optic technique of RI detection with a detector placed along the length of a fiber optic to measure the intensity of the transmitted mode-filtered light to ensure a low background and a signal-to-noise ratio advantage over conventional approaches [8][9][10].CE, combined with MFLD, is a novel approach suitable for a wide range of analytes without pretreatment. Previously, glycine and glutamic acid were separated and assayed in an unmodified fiber/capillary annular column sensing system.…”

Mode-filtered light methane gas sensor based on cryptophane A

“…However, most of these sensors have high background transmitted lights which lead to lower signal-to-noise ratio (S/N). By contrast, other fiber-optic sensors based on mode-filtered light detection were firstly designed by Synovec and co-workers [7][8][9]. The mode-filtered light that emanated from the fiber was collected by a detector positioned alongside the fiber.…”

“…Comparatively, this type of sensors substantially increases the S/N. Since the inception of this sensing technique, it has been widely applied to various liquid samples, such as aromatic and chlorinated hydrocarbons [7][8][9][10], ethanol [11,12], glucose and glycerol [13], acetic acid [14], and amino acids [15,16]. So far, only a few gas samples were studied at steady-state concentrations by heated annular column [9].…”

Mixed C18 and C1 modification on an optical fiber for chromatographic sensing

“…In complex systems, however, selectivity is a significant parameter to be considered in the construction of FOCS. Recently, some effort has been directed at developing chemical sensing technologies, based on a chromatographic separation approach with the goal of simultaneous and selective sensor responses to multiple components [6][7][8][9][10]. This work was called the optical fiber chromatographic sensing technique and was accomplished by coating a thin-layer stationary phase along an optical fiber and inserting the modified fiber into a capillary column.…”