Sensitive chemiluminescence determination of phentolamine mesylate and phenoxybenzamine hydrochloride based on K3Fe(CN)6-H2O2-fluorescein

► A-adrenoreceptor blockers enhanced the CL of K3Fe(CN)6-H2O2-fluorescein in NaOH. ► The possible enhancement mechanism is discussed. ► Detecting two kinds of α-adrenoreceptor blockers in pharmaceutical preparations.