Direct quantitation of the preservatives benzoic and sorbic acid in processed foods using derivative
Tomoharu Fujiyoshi1, Takahito Ikami2, Koji Kikukawa3
1Food Analysis Technology Center SUNATEC, 9-5 Akahorishinmachi, Yokkaichi, Mie 510-0825, Japan; College of Bioscience and Biotechnology, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi 487-8501, Japan.
Abstract:
The preservatives benzoic acid and sorbic acid are generally quantified with separation techniques, such as HPLC or GC. Here we describe a new method for determining these compounds in processed food samples based on a narrowness of the UV-visible spectral band width with derivative processing. It permits more selective identification and determination of target analytes in matrices. After a sample is purified by micro dialysis, UV spectra of sample solutions were measured and fourth order derivatives of the spectrum were calculated. The amplitude between the maximum and minimum values in a high-order derivative spectrum was used for the determination of benzoic acid and sorbic acid. Benzoic acid and sorbic acid levels in several commercially available processed foods were measured by HPLC and the proposed spectrometry method. The levels obtained by the two methods were highly correlated (r2>0.97) for both preservatives.
