Determination of Phytic Acid in Foods by Ion Chromatography with Post‐Column Derivatization

Abstract

An ion chromatographic method to determine phytic acid in foods, which allows for the direct injection of extracts into the column without need of a prepurification step, was developed. Infant formula powder, soy flour, soy isolate, wheat bran, and wheat bread were analyzed using the new ion chromatographic method and an ion exchange method. Phytic acid determined with the ion chromatographic method ranged from 0.2% for infant formula powder to 3.28% for wheat bran. The generally lower values found using the ion chromatographic method compared to the ion exchange method are attributed to the measurement of interfering substances such as breakdown products of phytic acid by the ion exchange procedure.

Phytate in foods and significance for humans: Food sources, intake, processing, bioavailability, protective role and analysis

“…One method could be the detection by Rounds and Nielsen [408] using the Fe 3+ -sulfosalicylate complex which was successfully applied by Oberleas and Harland in their interlaboratory comparison trial [439] or the highly sensitive determination of Mayr by means of the Ytrium -PAR complex detection [409]. Another opportunity for in-line detection of inositol phosphates is the iron detection (Fe 3+ ) of Phillippy et al [405] which has shown to be sensitive along with high stability and good reproducibility [159,405]. There might be other methods of specific, simple, fast and reliable determination of phytic acid and other inositol phosphates in foods and the future will show which method of determination and detection will be most suitable to determine phytic acid in foods and diets.…”

“…In 1985 Phillippy and Johnston [405] and later Phillippy et al [15] showed good separation of a great number of different inositol phosphates on a strong anion exchange AS3 column (Dionex) by using an HNO 3 gradient (0 -0.155 M HNO 3 ). This eluent offered reliable and sensitive inline detection of inositol phosphates by complexing the phosphate groups by means of Fe 3+ -ions.…”

Analysis of phytate in raw and cooked potatoes

“…The eluate was combined with 0.1% Fe(NO 3 ) 3 in 2% HClO 4 at a total flow rate of 1.5 mL/min in a plastic tee, and the UV absorbance was monitored at 290 nm in a Waters Lambda Max Model 480 LC Spectrophotometer (Phillippy and Johnston, 1985). Ten microgram external standards of dodecasodium phytate were analyzed before and after every two sample solutions.…”

High performance liquid chromatography analysis of phytate (IP6) in selected foods

“…Analytical methodology has evolved to improve the specificity, sensitivity and accuracy of phytate analysis. HPLC has become the technology of choice with a variety of detectors and several attempts have been made toward providing reliable methodology (Tangendjaja et al, 1980;Phillippy and Johnston, 1985;Sandberg and Ahderinne, 1986;Lehrfeld, 1989) with slightly differing analytical results. Phytate is a difficult molecule to analyze because it has no spectrum and may be hydrolyzed into lower esters with similar chemical properties, i.e., IP5, IP4, and IP3.…”