A novel sensor of potassium ions based on mode-filtered light detection

A novel potassium ions sensor based on mode-filtered light detection was reported. The analyzer was consisting of an optical fiber immobilized with a dye of bromocresol green and a fused-silica capillary. It was found that mode-filtered light intensity decreased with the concentration of potassium ions and a linear detection range of 0.25–20 mmol/L (R2 = 0.9977) was obtained with a detection limit of 9 × 10−5 mol/L as well as fast response, good reproducibility and reversibility in the working concentration range.