Origin and features of the electrochemiluminescence of luminol – Experimental and theoretical investigations

A general E-E/C mechanism for the counter-peak in luminol electrochemiluminescence

“…At this potential, OH À could be oxidized to O 2 via the intermediate HO À 2 in alkaline aqueous [7]. Moreover, the formation of L produced by further electro-oxidation of L .À was confirmed by both experimental [33] and theoretical [11] studies. As a result, ECL-4 was generated by the reaction of L with HO À 2 according to the mechanism shown in Scheme 1.…”

“…The reaction of L with OH À was considered to be a dark pathway due to the rather low CL efficiency [31]. The direct electro-oxidation of L under alkaline conditions was also a dark pathway according to the previous work [11]. Since ECL-4 and ECL-5 exhibited identical ECL properties in all conditional experiments above, we believed that ECL-5 was the counter-peak of ECL-4 and followed the same mechanism as ECL-4.…”

“…ECL is conventionally initiated by applying various electropulse signals such as symmetric double-step potential [6,7], triangle pulse [8], and low-frequency [9] and high-frequency [10] square-wave potentials in order to obtain strong ECL intensity and high sensitivity. Alternatively, cyclic voltammetry [11][12][13][14][15][16][17][18][19][20][21][22][23][24] and linear sweep voltammetry [12] have also been utilized to generate ECL in different ECL systems, such as luminol [11][12][13][14][15], lucigenin [16,17], tris-(2,2 0 -bipyridyl) ruthenium (II) (TBR) [18][19][20], and semi-conductor nanoparticles [21][22][23][24] at various electrode materials by several groups. The curves of ECL intensity (I ECL ) versus potential (E) (I ECL -E curves) were obtained when such potential-scanning electrochemical techniques were utilized instead of potential-step methods.…”

A Review of Electrogenerated Chemiluminescent Biosensors for Assays in Biological Matrices

“…The mechanism for luminol ECL has been studied by various groups and depends on the oxidant species and voltage applied [44][45][46][47][48][49]. The reaction occurs most efficiently under alkaline (pH 8.0-8.5) conditions, when luminol has been deprotonated (pK a1 = 6.2).…”

Direct electrogenerated chemiluminescence detection in high-performance liquid chromatography for determination of ofloxacin

“…(ii) The electrochemical initiation of the ECL reaction and variations of the potential introduce a great temporal control over the reaction and can improve selectivity. (iii) The [19,20] and luminol [21,22]. In contrast with indirect ECL, organic molecules having structural character capable of direct ECL have been explored relatively infrequently when compared to Ru(bpy) 3 2+ and luminol ECL.…”