title: Rapid determination of nucleotides in infant formula by means of nano-liquid chromatography.
abstract: A rapid method for the quantification of five ribonucleotides 5'- monophophates (adenosine, cytidine, guanosine, inosine, uridine, 5'-monophosphate), in infant formula, has been proposed using nano-LC. To separate the studied compounds, capillary columns packed with different C18-based stationary phases were investigated. All the columns tested were laboratory prepared. The experiments were performed in ion-pairing RP chromatographic mode using tetrabutylammonium hydroxide as ion-pairing reagent. The method was developed using a core-shell XB-C18 capillary column with a mobile phase consisting of 5% v/v methanol and 95% v/v 100 mM ammonium formate, pH 8, containing 20 mM tetrabutylammonium hydroxide. All compounds were baseline resolved in less than 5 min with a flow rate of 500 nL/min in isocratic elution mode. Nucleotides were detected at 260 nm. Analytical validation parameters were evaluated. The RSD values for intraday and interday repeatability for retention time and peak area were <2.4 and 4.2%, respectively. The method linearity was good (R(2) < 0.9995) for the studied compounds. LOD and limit of quantitation were 0.25 and 0.50 μg/mL, respectively. The method was applied to the determination of nucleotides in infant formula, subjected to a centrifugal ultrafiltration process, prior their analysis. The amounts found were in agreement to the labeled contents.
authors.affiliation: Istituto di Metodologie Chimiche, Consiglio Nazionale delle Ricerche, Monterotondo, Italy.|Departamento de Química Analítica, Nutrición y Bromatología, Facultad de Ciencias Químicas, University of Salamanca, Salamanca, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Mateos-Vivas
authors.affiliation: Istituto di Metodologie Chimiche, Consiglio Nazionale delle Ricerche, Monterotondo, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Fanali
authors.affiliation: Departamento de Química Analítica, Nutrición y Bromatología, Facultad de Ciencias Químicas, University of Salamanca, Salamanca, Spain.
authors.forename: Encarnacíon
authors.initials: E
authors.lastname: Rodríguez-Gonzalo
authors.affiliation: Departamento de Química Analítica, Nutrición y Bromatología, Facultad de Ciencias Químicas, University of Salamanca, Salamanca, Spain.
authors.forename: Rita
authors.initials: R
authors.lastname: Carabias-Martínez
authors.affiliation: Istituto di Metodologie Chimiche, Consiglio Nazionale delle Ricerche, Monterotondo, Italy.
authors.forename: Zeineb
authors.initials: Z
authors.lastname: Aturki
mesh_terms: D002853:Chromatography, Liquid / Q000379:methods*; D007225:Infant Food / Q000032:analysis*; D036103:Nanotechnology; D009711:Nucleotides / Q000032:analysis*; D015203:Reproducibility of Results; D013056:Spectrophotometry, Ultraviolet
chemical_list: D009711:Nucleotides
keywords: Infant formula; Ion pair reversed-phase chromatography; Nano-LC; Nucleotide 5′-monophosphates