What do 3-MCPD and 2-chloroethanol have in common?

Study on the alternative source of false positive findings for 2-chloroethanol in dietary supplements

A. Romanotto, D. Bertuola, B. Ramm

With our research we could prove the clear relationship between the 2-chloroethanol (2-CE) findings and polyethylene glycol (PEG) or ethylene glycol (EG) presence especially in food supplement samples. With this we can now provide an explanation for 2-CE as a false positive or focus the differences in the analysis results when using different methods. It is known, that results of HS-GC-MS vs. GC-MS/MS analyses, particularly in food supplements, often do not match or sometimes are contrary.

Our study examined different combinations in applications of EG and PEG in the presence and absence of chloride ions for the formation of 2-CE. Before we tested and verified the development of 2-CE from EG and PEG in the injector of GC. In the next step freshly harvested dried and powdered dandelion root samples were differently treated with EG and PEG. Clear formation of 2-CE was observed, particularly after treating the samples with EG/PEG in the presence of chloride ions (HCl) but also without HCl and measuring with GC-MSMS.

PEG as a source for 2-CE in food supplements can now be considered as a ubiquitous compound. The most important sources of EG units include the following:

• E1521 as a food additive [1], up to 10 g/kg are allowed in food supplements
• Packages: Food contact materials, various esters of PEG mentioned in the regulation [2]
• Modified PEG substances in agricultural use
• Ingredient in cosmetics, tooth cleaning tablets, bath additives, liquid soaps up to 1 %

For proving of this hypothesis 30 food supplement samples were tested using HR-LC-MS for 40 different PEG compounds including esters and derivatives. In products with high levels of 2-chloroethanol using GC-MSMS we could also detect high levels of various PEG compounds.

This is the reason for the differences in results between HS-GC-MS and GC-MSMS analyses, whereby the GC-MSMS measurement can lead to false-positive results. This cannot happen when measuring with HS-GC-MS, as glycols are not volatile and 2-CE cannot therefore be formed in absence of glycols. The drafted path of 2-CE formation from EG/PEG is comparable to that of 3-MCPD from diglyceride ester.

In the presence of chloride ions and water elimination in GC-injector or drying, 2-CE can be formed from released EG [3]. HCl as a source of the chloride can at the same time be formed from organochlorine substances in injector [4].

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