Development and validation of an improved method for determination of chloropropanols in paperboard food packaging by GC-MS

Paper used for food packaging is often manufactured with wet strength resin additives to impart moisture resistance. Wet strength resins formulated with epichlorohydrin form undesirable chloropropanol type by-products including 3-chloro-1,2-propanediol (3-MCPD) and 1,3-dichloro-2-propanol(1,3-DCP). Chloropropanols are suspect carcinogens. These compounds were recently added to the California Proposition 65 list (known or suspect human carcinogens) which mandates labeling of products sold in the state of California, creating a dilemma for food packaging processors. Food packaging manufacturers are concerned with migration of chloropropanols from packaging into foods or beverages. Therefore, analytical methods for determination of chloropropanols in paperboard food packaging are of great importance. However, previously described methods are not developed for paperboard food packaging samples, or not for EU standard aqueous extraction study of paperboard samples. The objective of this research is to develop an improved analytical method for determination of 3-MCPD and 1,3-DCP in paper type food packaging. The refined method uses aqueous extraction, matrix-spiking of a deuterated surrogate internal standard (3-MCPD-d5), cleanup using Extrelut solid phase extraction, derivatization using silylation reagent, and GC-MS analyses of the chloropropanols as their corresponding trimethyl silyl ethers. The new method is applicable to paper type food packaging sample for EU standard aqueous extraction study and aqueous food stimulant migration test. Also, the method uses 10 times less sample size, solvents and reagents than previously described methods, reducing the cost and time for analysis. The derivatization procedure was also improved. The overall validation data suggest the method is precise and rugged. The limit of detection of aqueous extract is 0.010 ppm (w/w) for both 3-MCPD and 1,3-DCP. Analytical system precision is 3.36%RSD for 3-MCPD and 7.65%RSD for 1,3-DCP. The new method has been applied to the analysis of over 100 commercial paperboard packaging samples. The data is being used to guide development of next generation wet strength resins with reduced chloropropanols content, and also used for risk assessments to calculate VSD (virtual safe dose).M.S.Includes bibliographical referencesby Wan-yun Li