Determination of choline in milk and infant formulas by enzymatic analysis: collaborative study

A collaborative study was conducted on a coupled enzymatic-spectrophotometric method for the determination of choline in infant formula and milk powders. Twenty-nine laboratories participated in the analysis of 8 blind duplicates over the range of 45-175 micrograms/100 g sample. After the combined a...

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Bibliographic Details
Published inJournal of AOAC International Vol. 83; no. 1; p. 131
Main Authors Woollard, D C, Indyk, H E
Format Journal Article
LanguageEnglish
Published England 01.01.2000
Subjects
Alcohol Oxidoreductases - metabolism
Ampyrone
Animals
Calibration
Choline - analysis
Enzymes
Humans
Hydrogen-Ion Concentration
Hydrolysis
Infant Food - analysis
Laboratories - standards
Linear Models
Milk - chemistry
Peroxidase - metabolism
Phenol
Phospholipases - metabolism
Quality Control
Reference Standards
Sensitivity and Specificity
Spectrophotometry
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Summary:A collaborative study was conducted on a coupled enzymatic-spectrophotometric method for the determination of choline in infant formula and milk powders. Twenty-nine laboratories participated in the analysis of 8 blind duplicates over the range of 45-175 micrograms/100 g sample. After the combined acid hydrolysis-phospholipase release of choline, incubation with choline oxidase in the presence of peroxidase and phenol generates a quinoneimine chromophore with 4-aminoantipyrine. Following raw data screening, overall mean RSDR was estimated at 5.14% (range, 4.26-6.34%) with a HORRAT value of 0.91 (range, 0.76-1.00) and an overall mean RSDr:RSDR value of 0.53 (range, 0.42-0.74). The method was also compared with alternative independent analytical techniques for several of the collaborative study samples.
ISSN:1060-3271
DOI:10.1093/jaoac/83.1.131