Review on recent applications of the liquid waveguide capillary cell in flow based analysis techniques to enhance the sensitivity of spectroscopic detection methods

Incorporation of long path length liquid waveguide capillary cell (LWCC or LCW) into spectrometric detection systems can increase the sensitivity of these by orders of magnitude (up to 500 times), and consequently can reduce the detection limits. The combination of the long path length spectrophotometry with flow methodologies can provide analytical solutions for various challenges in the field of environmental, biochemical and food chemistry. In this present work, the analytical applications of the long capillary cells are summarised and critically discussed. A historical overview of the cell development is given; applications in different areas are presented and grouped by analyte type. Major improvements achieved based on the use of the LWCC in the analytical characteristics (like sensitivity and detection limit) are emphasised while some of the limitations are also discussed.