Photometric detection in flow analysis systems using integrated PEDDs

This sensing concept has been applied in flow analysis by constructing an optical flow cell with a pair of LEDs. Calibration of the integrated optical flow cell using a dye resulted in a linear response that obeys the Beer-Lambert law. The flow rate, dynamic range, sensitivity and limits of detection were investigated. The system was also used for pH determination in the range of pH 2.5-6.8 using bromocresol green (BCG). The pKa of BCG was successfully determined by this technique.