MULTI-WAVELENGTH DETERMINATION OF COBALT BY TUNGSTEN COIL ATOMIC EMISSION SPECTROMETRY

A simple tungsten coil atomic emission device is used for the determination of Co in a polluted water sample. Multiple cobalt emission lines in the 340.5 to 352.7 nm range are detected simultaneously. Limits of detection at five different wavelengths ranged between 20 and 70 ng Co in a 25 mu L sample volume. Summing the signals for the five different Co emission lines improves the detection limit to 10 ng. The combination of the five lines also results in improved precision (2.2% relative standard deviation for a 4 mg/L Co solution) and accuracy (102% for a polluted water reference material).