Dual-light source excitation for mode-filtered light detection Original Research Article

The sensitivity of a multi-channel mode-filtered light detection system has been enhanced by using a dual-light source irradiation technique. The detection system was constructed from an annular column consisting of a bare optical fibre inserted into a capillary. Sample was introduced through the gap between the fibre and the capillary. A multi-channel charge-coupled device was set on the side of the capillary at which four detection windows could be simultaneously monitored. The changes in the intensities of the mode-filtered light on exposure to various concentrations of ethanol samples from each detection window were monitored. The theoretical studies on the sensitivity of detection of the detection system using dual-light source irradiation have been described. The sensitivity of detection was enhanced when a dual-light source instead of a single-light source was employed. The working concentration range for ethanol was 0–80% (v/v) ethanol. The limit of detection was determined to be 1% (v/v) ethanol. The proposed method has been successfully applied to the determination of ethanol contents of some wine samples. The results were satisfactory compared with values obtained from a standard reference method.