title: Determination of nitrite, nitrate, and glucose-6-phosphate in muscle tissues and cured meat by IC/MS.
abstract: The endogenous nitrate concentration in fresh meat and the residual nitrate and nitrite contents after curing are related to food quality and safety. Most ion chromatography (IC) methods suffer from interferences, especially in fresh meat samples, in which the endogenous nitrate content is low, and in cured meat products, in which other nitrogenous compounds can interfere with the separation of inorganic anions. One of the major classes of interfering compounds in fresh meat are sugar phosphates, which originate from glycolysis during the conversion of muscle glycogen to lactic acid. Nitrate can be separated from interfering compounds with a high-capacity anion-exchange column that was manufactured for use with hydroxide eluents (i.e., hydroxide-selective). This column has a different selectivity than traditional IC columns that use carbonate eluents and facilitates the determination of nitrate in both fresh and cured meats. Nitrate was detected by both suppressed conductivity measurement and mass spectrometry (MS). The identifications of nitrate and glucose-6-phosphate were confirmed by MS detection. The described IC/MS method is robust, sensitive to nitrate concentrations as low as 0.10 mg/kg, and can determine sugar phosphates that are useful for monitoring meat freshness. We successfully used this method to determine nitrate in nearly 100 muscle tissues and cured meat samples.
authors.affiliation: Stazione Sperimentale per l'Industria delle Conserve Alimentari, Meat Department, Viale Tanara 31/A 43100 Parma, Italy. giovanna.saccani@ssica.it
authors.forename: Giovanna
authors.initials: G
authors.lastname: Saccani
authors.forename: Enrica
authors.initials: E
authors.lastname: Tanzi
authors.forename: Silvano
authors.initials: S
authors.lastname: Cavalli
authors.forename: Jeff
authors.initials: J
authors.lastname: Rohrer
mesh_terms: D002623:Chemistry Techniques, Analytical / Q000379:methods*; D002845:Chromatography; D002852:Chromatography, Ion Exchange / Q000379:methods*; D005504:Food Analysis / Q000379:methods*; D005519:Food Preservation; D019298:Glucose-6-Phosphate / Q000032:analysis*; D013058:Mass Spectrometry / Q000379:methods*; D008461:Meat Products; D009132:Muscles / Q000378:metabolism*; D009566:Nitrates / Q000032:analysis*; D009573:Nitrites / Q000032:analysis*; D013997:Time Factors
chemical_list: D009566:Nitrates; D009573:Nitrites; D019298:Glucose-6-Phosphate