Improving the sensitivity of HPLC absorption detection by cavity ring-down spectroscopy in a liquid-only cavity

A previously described liquid-only cavity flow cell is used to assess the feasibility of improving absorbance detection limits in liquid chromatography (LC) using cavity ring-down spectroscopy (CRDS). In this miniaturized cavity there is an optical path length of only 2 mm between the mirrors, which at the same time form the walls of the flow cell. Typical ring-down times are 65-75 ns for the eluent blank. The performance of the presented flow cell compares favorably to conventional absorbance detection: the baseline noise is determined to be 2.7 × 1