Contaminants

Background: 

Folic acid (vitamin B9) is a water-soluble vitamin that occurs naturally in many kinds of fruit and vegetables, wholemeal cereals and animal source foods. An adequate supply of folic acid is particularly important for expectant mothers during certain phases of pregnancy. It is available on the market in the form of food supplements, enriched foodstuffs and medicinal products. However, folic acid may be contaminated with carcinogenic N-nitroso folic acid under certain circumstances. A strict limit value has therefore already been imposed for pharmaceutical products. Due to the particularly sensitive nature of the target group, the possibility of testing for N-nitroso folic acid should also be considered with respect to the use of folic acid in food supplements.

N-nitroso folic acid in food supplements?

In its “Risk assessment of N-nitrosamines in food” (EFSA 2023), the European Food Safety Authority (EFSA) draws attention to the fact that, in some cases, the margin of exposure (MOE) is likely to be significantly lower than the targeted MOE of at least 10,000 for all consumer groups. According to the current state of knowledge, this can primarily be attributed to meat, fish, beer and other alcoholic and non-alcoholic beverages. However, there are many foodstuffs for which hardly any data are available. The EFSA therefore recommends that the European Commission should develop a screening method for the 10 most common carcinogenic nitrosamines (TCNAs) with particular focus on the testing of processed foods. Although the EFSA document also draws attention to the occurrence of N-nitroso folic acid, in the absence of analysis data for foodstuffs, folic acid has not been taken into closer consideration as a potential source of nitrosamines. Nevertheless, a recent document published in 2024 confirms that N-nitroso folic acid can also be found in food supplements containing folic acid (Zeng et al. 2024).

N-nitroso folic acid in pharmaceutical products

Since carcinogenic N-nitrosamines were detected in the group of angiotensin II receptor blockers (ARBs or sartans) in 2018, N-nitrosamines have been found in numerous other medicinal substances. These include folic acid, from which N-nitroso folic acid can be formed under the influence of sodium nitrite. The European Medicines Agency (EMA) and the U.S. Food and Drug Administration (U.S. FDA) have therefore specified 1,500 ng/day as the maximum permitted daily intake of N-nitroso folic acid (EMA 2025, U.S. FDA 2023).

Determination of N-nitroso folic acid

PhytoLab has developed a method for precise determination of N-nitroso folic acid by means of state-of-the-art technology. The LC-MS/MS method has been comprehensively validated on food supplements containing folic acid in accordance with the ICH guidelines (ICH Q2). It enables determination of N-nitroso folic acid in pharmaceuticals, and in mono- and multivitamin preparations and ingredients with a limit of quantification of 10 μg/kg. Apart from performing routine analyses, we keep a CTD-compliant document package, comprising test method and validation reports available for our pharmaceutical customers. We can also conduct a product-specific verification procedure for your product, if required.

Please contact us to find out about the possibilities that PhytoLab can offer you in its capacity as your competent and reliable partner in the field of nitrosamine analysis.

Sources

CMdH 2025: Heads of Medicines Agencies: Nitrosamine impurities (accessed 26.02.2025)
EFSA 2023: Risk assessment of N-nitrosamines in food. EFSA Journal 2023;21(3):7884
FDA CDER 2025: https://www.fda.gov/regulatory-information/search-fda-guidance-documents/cder-nitrosamine-impurity-acceptable-intake-limits (accessed 26.02.2025)
Yun Zeng, Jessie Teo, Jing-Quan Lim, Wei-Kiat Hoi, Chee-Leong Kee, Min-Yong Low & Xiaowei Ge (2024) Determination of N-nitroso folic acid in folic acid and multivitamin supplements by LC-MS/MS, Food Additives & Contaminants: Part A, 41:1, 1-8, DOI: 10.1080/19440049.2023.2292603

Your contacts at PhytoLab:

Analysis:

NADJA KONEBERG
Phone +49 9163 88-589
nadja.koneberg@phytolab.de

Sales:

ELKE LENZER
Phone +49 9163 88-597
sales@phytolab.de