Organo-modified layered double hydroxide-catalyzed Fenton-like ultra-weak chemiluminescence for specific sensing of vitamin B12 in egg yolks

In general, the chemiluminescence (CL) sensing of vitamin B12 is achieved by determining Co(II) liberated from acidified vitamin B12 by a luminol system. However, the luminol system for sensing vitamin B12 has poor selectivity due to serious interference from other metal ions. In this study, as a novel CL amplifier of the Co(II)+H2O2+OH− ultra-weak CL reaction (Fenton-like system), dodecylbenzene sulfonate (DBS)–layered double hydroxides (LDHs) have been applied to the specific determination of vitamin B12 by liberating Co(II). The CL intensity increased with increasing the concentration of vitamin B12 in a wide range from 1.0 ng mL−1 to 5 μg mL−1 with a detection limit of 0.57 ng mL−1 (S/N=3). The proposed method has been successfully applied to determine vitamin B12 in egg yolk with simple procedures, shorter time and higher selectivity. Recoveries from spiked real samples were 96–103%. The results of the proposed method for sensing vitamin B12 in real samples were agreed with those obtained by the standard inductively coupled plasma mass spectrometry (ICP-MS) method. To the best of our knowledge, this is the first report on the CL sensing of vitamin B12 with high selectivity in the absence of luminol.