Mass spectral determinations of the folic acid content of fortified breads from Chile

Robert J. Pawlosky*, Eva Hertrampf, Vincent P. Flanagan, Paul M. Thomas

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

19 Scopus citations


Sixty-four samples of fortified bread that were collected from 50 bakeries within the vicinity of Santiago, Chile were assayed for their folic acid content using a high-performance liquid chromatography-mass spectrometry (LC-MS) procedure with stable-isotope dilution. A 13C5 analogue of folic acid was spiked into each sample as an internal standard and the analyte was extracted from bread into a phosphate buffer, purified on a solid phase cartridge, and analyzed by LC-MS in the negative ion mode using electrospray ionization. The relative standard error for the precision of the method was 3.8% based on the analyses of five replicate samples. The accuracy of the method was determined using a standard method of addition of the analyte into bread samples and folic acid was quantified over a concentration range that bracketed the fortification levels (100-900 ng g-1 of bread). A subset of bread samples (n = 14) was also assayed using a microbiological assay (L. casei) and the results of these analyses were compared with the LC-MS determinations. The mean variation in the values as determined by the microbiological assay and the LC-MS method was on the order of 10%. Overall, it was found that in 38% of the bakery samples, the concentrations of folic acid were within the target values as specified by the program (151 and 264 μg g-1). Nineteen percent of the samples had folic acid concentrations that were below 151 μg g-1 and 43% of the samples exceeded the upper level.

Original languageEnglish (US)
Pages (from-to)281-286
Number of pages6
JournalJournal of Food Composition and Analysis
Issue number3
StatePublished - Jun 2003


  • Folic acid
  • Fortified bread
  • Isotope dilution
  • Mass spectrometry

ASJC Scopus subject areas

  • Food Science


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