title: Synthesis of a novel fluorescent probe based on 7-nitrobenzo-2-oxa-1,3-diazole skeleton for the rapid determination of vitamin B12 in pharmaceuticals.
abstract: A new fluorescent probe, 4-N,N-di(2-hydroxyethyl)imino-7-nitrobenzo-2-oxa-1,3-diazole (HINBD) was synthesized in a single step with reasonably good yield. The water-soluble HINBD emits strongly in the visible region (λex  = 479 nm, λem  = 545 nm) and is stable over a wide range of pH values. It was found that vitamin B12 (VB12 ) had the ability to quench the fluorescence of HINBD, and the quenched fluorescence intensity was proportional to the concentration of VB12 . A method for VB12 determination based on the quenching fluorescence of HINBD was thus established. Interference effects of various substances, including sugars, vitamins, amino acids, inorganic cations and some organic substances have been studied. Under optimal conditions, the linear range is 0.0-2.4 × 10(-5)  mol/L. The determination limit is 8.3 × 10(-8)  mol/L. The method was applied to measure VB12 in pharmaceutical preparations with satisfactory results.
authors.affiliation: School of Chemistry and Chemical Engineering, Shanxi University, Taiyuan, 030006, People's Republic of China.
authors.forename: Zhuo Bin
authors.initials: ZB
authors.lastname: Shang
authors.forename: Ya Juan
authors.initials: YJ
authors.lastname: Wen
authors.forename: Xiao Qing
authors.initials: XQ
authors.lastname: Yan
authors.forename: Huan He
authors.initials: HH
authors.lastname: Sun
authors.forename: Yu
authors.initials: Y
authors.lastname: Wang
authors.forename: Wei Jun
authors.initials: WJ
authors.lastname: Jin
mesh_terms: D005456:Fluorescent Dyes / Q000138:chemical synthesis* / Q000737:chemistry*; D015394:Molecular Structure; D009578:Nitrobenzenes / Q000138:chemical synthesis / Q000737:chemistry*; D010069:Oxadiazoles / Q000138:chemical synthesis / Q000737:chemistry*; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D014805:Vitamin B 12 / Q000032:analysis*
chemical_list: C000588943:7-nitrobenzo-2-oxa-1,3-diazole; D005456:Fluorescent Dyes; D009578:Nitrobenzenes; D010069:Oxadiazoles; D004364:Pharmaceutical Preparations; D014805:Vitamin B 12
keywords: 7-nitrobenzo-2-oxa-1, 3-diazole; Diethanolamine; Fluorescence quenching; VB12