Preparation of a multiple interacting magnetic fluid for rapid and sensitive simultaneous extraction of β-nicotinamide mononucleotide metabolites in biological samples.

Background: β-nicotinamide mononucleotide stands out as an essential breakthrough in "anti-aging" and consistently leads the list of top-selling nutritional supplements in terms of quantity. As the metabolites of β-nicotinamide mononucleotide, the detection of nicotinamide and N-methylnicotinamide is of great significance for evaluating the nutritional effect of dietary supplements of β-nicotinamide mononucleotide. However, due to the extremely low concentration of nicotinamide and N-methylnicotinamide in vivo and the serious matrix interference in biological samples, there is an increasing demand for materials and methods of pre-treatment.

Results: In this study, FeO@hydroxypropyl methyl cellulose@dodecylbenzenesulfonic acid magnetic fluid was synthesized for the first time, and it was used as pretreatment material to detect nicotinamide and N- methylnicotinamide in urine samples by high performance liquid chromatography. Compared with other adsorption materials, FeO@hydroxypropyl methyl cellulose@dodecylbenzenesulfonic acid nanoparticles are a kind of uniform magnetic fluid. Furthermore, they have more types and quantities of interaction sites (electrostatic interactions, hydrophobic interactions, hydrogen bonding interactions, and π-π interactions), so they own greater adsorption capacity. When the pH of the solution is 4, they can be adsorbed quickly within 10 s. The method successfully detected trace nicotinamide and N-methylnicotinamide in urine samples in the linear range of 0.1-80 μg mL, the low detection limits were 0.30 ng mL and 1.5 ng mL respectively, and the quantification limits were 1.0 ng mL and 5.0 ng mL, respectively. At the same time, the standard urine samples of nicotinamide and N-methylnicotinamide showed satisfactory recovery rate 94.50-109.1 %. The results indicated that the established method can accurately and quantitatively determine trace nicotinamide and N-methylnicotinamide in urine samples.

Significance: Consequently, low concentration of β-nicotinamide mononucleotide metabolites can be detected simultaneously, and the interference can be eliminated during the detection process, which provides an efficient and convenient pretreatment method and a rapid and sensitive detection method for the analysis of β-nicotinamide mononucleotide metabolites. What's more, it has a wide application prospect in the analysis of other similar metabolites in biological samples.