Method for the accurate determination of phytic acid in beverages by liquid chromatography-mass spectrometry after methylation with (trimethylsilyl) diazomethane

Phytic acid (PA) plays different roles in various fields of study, yet current analytical methods for PA detection are still unsatisfactory. A novel method has been presented for the determination of PA in beverages, based on complete methylation in combination with liquid chromatography-mass spectrometry (LC-MS) analysis. By treatment with (trimethylsilyl) diazomethane, all the polybasic acid groups in PA were converted to the corresponding ester, and thus the corresponding derivative was easily analyzed by LC-MS. The addition of ethylenediamine tetraacetic acid (EDTA) to the derivative solution improved the sensitivity and the reproducibility in the PA analysis. Under optimized parameters, the linear range of the PA detection was 0.5–100 μg/L, the limit of detection was 0.075 μg/L, the limit of quantitation was 0.25 μg/L, and the recovery range was 81.3–119.7 %. The PA content was determined for 13 commercially available beverage samples, and experimental results showed that this method provided a practical and reliable method for the detection of PA across diverse beverage matrices. •Current analytical methods for phytic acid are still unsatisfactory.•Complete methylation of phytic acid was performed by treatment with (trimethylsilyl) diazomethane.•The complete methylated product was easily analyzed by LC-MS.•Addition of EDTA to the analyte solution greatly improved the sensitivity of the PA detection.•The PA content in several beverages was determined.