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.

Bidirectional ATP-driven transport of cobalamin by the mycobacterial ABC transporter BacA

“…Hence, development of alternative transport assays that support high-throughput experiments are desirable. Methods established in the past to detect cobalamin in solution or in cellular or liposomal compartments without the use of radioactive substrates [32][33][34][35][36][37][38][39][40][41] often do not allow for high-throughput measurements, or are incompatible with assays to measure transport in both import and export direction. We chose to use a protein-based sensor derived from the SBP BtuF 25 .…”

Fluorescent Vitamin B12–Platinum(II) Derivatives as Potential Metallotheranostic Agents for the Treatment and Imaging of Tumors

“…Several methods have been reported to date to identify, quantify, and track cyanocobalamin, including optical spectroscopy, chemiluminescence, surface plasmon resonance, Raman spectroscopy, as well as absorption and fluorescence spectroscopy [61]. Although vitamin B 12 is an inadequate luminescent species, its presence in solution can be detected indirectly through interaction with light-emitting molecules, such as acridine orange, rhodamine 6G, and 4-N,N-di(2-hydroxyethyl)imino-7nitrobenzo-2-oxa-1,3-diazole (HINBD) [62,63]. In all cases, vitamin B 12 has been shown to quench the fluorescence of the object fluorophores, thus allowing its indirect detection by fluorescence-based analytical techniques.…”

Measuring and tracking vitamin B12: A review of current methods with a focus on optical spectroscopy

“…While vitamin B12 is a poor light emitter itself, and its intrinsic absorption at biologically relevant concentrations is too small for direct detection, its presence can affect the efficiency of other light-emitting species. Rhodamine 6G, for example, has been used to indirectly measure vitamin B12 in solution by studying the effect B12 has on the fluorescence resonance energy transfer between aridine orange (AO) and Rhodamine 6G (93), illustrated by the collected spectra shown in Figure 5 the intensity of the fluorophore's signal (95). This technique demonstrated a LOD of 0.1 mg/ mL in water.…”