Source Light Pathways Inside a Long capillary Cell Used for Colorimetry

Long capillary cell (LCC) is found to be so effective to detect the ultra-minute absorption of solution, that more than 104 times enhancement in absorbance can be attained with the necessary sample volume limited to a few ml. With this cell, the absorbance of solution is amplified several times higher than that expected from the cell length, and the observed calibration curve provides a strong curvature. Such characteristics of LCC are ascribable to the multi-reflection of source light inside the cell. Reflection petterns of source light in side LCC have been, therefore, discussed in relation to the enhancement of the absorption and anlytical calibration curves.