Determination of hydrogen peroxide in natural waters by stopped-flow injection analysis with chemiluminescence detection

A rapid, sensitive flow injection (FI) method with chemiluminescence (CL) detection for the determination of trace amounts of hydrogen peroxide in natural water is described. This method is based on the reaction of luminol with hydrogen peroxide catalysed by cobalt(II) in an alkaline medium. Sodium dodecyl sulphate (SDS) was used as sensitizer agent, and its presence greatly accelerated the reaction and enhanced the CL intensity. An FI stopped-flow technique was introduced to the CL reaction to increase sensitivity. Optimal conditions for the chemiluminescence reaction were examined. The sampling frequency was 50 hr⁻¹ for injection volumes of 100 µL. The detection limit of hydrogen peroxide, defined as 3 times the standard deviation of the blank, was 0.5 nM in high purity water, and the working linear range was 1 to 105 nM. For the determination of 15 nM and 52 nM hydrogen peroxide, the relative standard deviations were 2.8 and 2.3% respectively (n = 11). The method has been applied to the determination of hydrogen peroxide in natural water samples. © 2000 John Wiley & Sons, Inc. Lab Robotics and Automation 12:149–156, 2000