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ARS Home » Northeast Area » Beltsville, Maryland (BHNRC) » Beltsville Human Nutrition Research Center » Food Composition and Methods Development Laboratory » Research » Publications at this Location » Publication #129442
Title: EVALUATION OF NIACIN LC METHODS BY DIODE ARRAY/SPECTRAL ANALYSIS

Author
item Lacroix, Denis
item Wolf, Wayne
item HINDSLEY, THOMAS - 1235-15-00

Submitted to: Analytical Letters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/26/2002
Publication Date: 3/1/2002
Citation: Lacroix, D.E., Wolf, W.R., Hindsley, T.M. 2002. Evaluation of niacin lc methods by diode array/spectral analysis. Analytical Letters. 35(13):2173-2184.

Interpretive Summary: Three extraction/LC methods for determination of niacin and or nicotinamide in several food based reference materials have been evaluated by spectral analysis methods using a photodiode array detection system. This system allows visual inspection of multiple wavelength scans to identify absence of multiple components under LC peaks and also calculation of a Similarity Index (SI), which compares the spectra of a LC peak to that of a library standard. Niacin can occur in foods as nicotinic acid or as added nicotinamide to enrich foods. Spectral analysis showed a single component peak (SI>0.99) for nicotinic acid by anion exchange LC using a cation exchange solid phase extraction following a standard H2SO4 digest, and for nicotinamide by reverse phase (RP) LC following a trichloroacetic acid extraction. A RP/LC method for nicotinamide involving meta- phosphoric acid extraction is not as satisfactory, since it contains interfering components under the LC peak (SI= 0.81). LC methods for niacin can replace more laborious microbiological methods for use by food testing laboratories to generate data for food compositional tables and in response to food labeling regulations.

Technical Abstract: Three extraction/LC methods for determination of niacin and or nicotinamide in foods have been evaluated by spectral analysis methods using a photodiode array detection system. This system allows visual inspection of multiple wavelength scans to identify absence of multiple components under LC peaks and also calculation of a Similarity Index (SI), which compares the spectra of a LC peak to that of a library standard. Niacin can occur in foods as nicotinic acid or as added nicotinamide to enrich foods. Food based reference materials utilized for our evaluation included: SRM-1846 Infant Formula (NIST), RM 8437 Hard Red Spring Wheat (NIST), and VMA 195 Cereal (AACC). Spectral analysis showed a single component peak (SI>0.99) for nicotinic acid by anion exchange LC using a cation exchange solid phase extraction following a standard H2SO4 digest, and for nicotinamide by reverse phase(RP)LC following a trichloroacetic acid extraction. A RP/LC method for nicotinamide involving meta- phosphoric acid extraction is not as satisfactory, since it contains interfering components (SI= 0.81). LC methods for niacin can replace more laborious microbiological methods.