Analysis of diglycolic acid in food packaging, over the counter products, direct additive carboxymethyl cellulose, and retail foods

ABSTRACT

Carboxymethyl cellulose (i.e. CMC or cellulose gum) is used as a direct additive for foods and drugs to change texture and act as a binder. CMC can also be a fluid absorbent used in food packaging and food contact materials. CMC and other carboxymethyl starches are synthesised by condensing glycolic acid with monochloroacetic acid. Diglycolic acid (DGA) is a byproduct produced by this condensation which cannot be completely removed. Currently, there are no analytical methods to accurately detect and quantify DGA in foods and food packaging materials. A method using a methanol/water extraction coupled with weak anion exchange solid phase extraction cleanup for more complex matrices was developed. A novel LC-MS/MS method was used to determine the DGA concentration in food contact materials, food grade direct additive CMC, and foods containing CMC. This paper will discuss the development of a new method for the preparation and cleanup of various food matrices and LC-MS/MS analysis for the presence of DGA.

KEYWORDS:

• Carboxymethyl cellulose
• diglycolic acid
• LC-MS/MS
• method development

Acknowledgments

We thank William Limm, Chemist, for IR spectra, and Lili Fox Vélez, Scientific Writer, for scientific writing support. Both colleagues work in the Office of Regulatory Science, Center for Food Safety and Applied Nutrition, US FDA.

Disclosure statement

No potential conflict of interest was reported by the authors.