Instrument: Liquid Waveguide Capillary Cells
Liquid Waveguide Capillary Cells (LWCC) are optical sample cells that combine an increased optical pathlength (2-500 cm) with small sample volumes. They can be connected via optical fibers to a spectrophotometer with fiber optic capabilities. Similar to optical fibers, light is confined within the (liquid) core of an LWCC by total internal reflection at the core/wall interface. Ultra-sensitive absorbance measurements can be performed in the ultraviolet (UV), visible (VIS) and near-infrared (NIR) to detect low sample concentrations in a laboratory or process control environment. According to Beer’s Law the absorbance signal is proportional to chemical concentration and light path length.
These low level nutrient measurements were made with an LWCC (not the usual autoanalyzer). The methods were developed by Susan Curless and Mariona Segura-Noguera.