Detection of chromium in liquids by laser induced breakdown spectroscopy (LIBS)

Environmental concerns about the amount of dissolved heavy metals in coastal tidal waters have led to investigations into possible ways to detect chromium dissolved in water. A method using fluorescence spectroscopy in solution has been proposed. However, such optical emission spectroscopic methods tend to suffer from a lack of sensitivity caused by the strong quenching processes in liquids. In this investigation, Nd:YAG Q-switched laser pulses were utilised to generate a plasma filled bubble in a chromium solution. Fluorescence in the plasma was detected using an optical fibre tip placed adjacent to the bubble. Light wavelengths characteristic of chromium were detected and spectral images recorded using an optical multi-channel analyzer.