title: Determination of sodium in foods by flame atomic absorption spectrometry after microwave digestion: NMKL interlaboratory study.
abstract: Nine laboratories participated in an interlaboratory method performance (collaborative) study of a method for the determination of sodium in foods by flame atomic absorption spectrometry after wet digestion, using a microwave oven technique. Before the study, the laboratories were able to practice on samples with defined sodium levels (pretrial test). The method was tested on a total of 6 foods (broccoli, carrot, bread, saithe fillet, pork, and cheese) with sodium concentrations of 1480-8260 mg/kg. The materials were presented to the participants in the study as blind duplicates, and the participants were asked to perform single determinations for each sample. The repeatability relative standard deviations (RSDr) for sodium ranged from 1.9 to 6.5%. The reproducibility relative standard deviations (RSDR) ranged from 4.2 to 6.9%. The HorRat values ranged from 0.9 to 1.6.
authors.affiliation: National Institute of Nutrition and Seafood Research NIFES, PO Box 176 Sentrum, N-5804 Bergen, Norway. kju@nifes.no
authors.forename: Kaare
authors.initials: K
authors.lastname: Julshamn
authors.forename: Per
authors.initials: P
authors.lastname: Lea
authors.forename: Hilde Skaar
authors.initials: HS
authors.lastname: Norli
mesh_terms: D000704:Analysis of Variance; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D005504:Food Analysis / Q000379:methods; D006861:Hydrogen Peroxide / Q000032:analysis; D008872:Microwaves; D017942:Nitric Acid / Q000032:analysis; D012015:Reference Standards; D015203:Reproducibility of Results; D012964:Sodium / Q000032:analysis* / Q000494:pharmacology; D013054:Spectrophotometry, Atomic / Q000295:instrumentation / Q000379:methods*; D013696:Temperature
chemical_list: D017942:Nitric Acid; D012964:Sodium; D006861:Hydrogen Peroxide