“…However, the employment of fluorescence detection in our present method dramatically reduced the chromatographic background signals when the blood sample was analyzed, resulting in the achievement of a sample preparation with 5 times higher sensitivity using a simple purification procedure. For UV detection in the previous method, further complicated purification steps for sample preparation were required [13]; a process which most likely would yield quantitative errata because of the rapid continuous degradation of landiolol after blood sampling (even in cases where blood samples were immediately mixed with ice-cold ethanol after sampling, 10-30% of landiolol were degraded). Thus, the use of enzyme inhibitors, such as neostigmine in the present study, is essential to prevent landiolol degradation, especially when blood is collected in the operation theater.…”