Description
Quantification of total folate based on quantification of 6 folate vitamers, which contribute to the main folate activity. The method uses pure γ-glutamyl hydrolase, which enables efficient and rapid degradation of the polyglutamates to monoglutamates. LC-ESI-MS/MS quantifies monoglutamates using 13C5-labeled internal standards. In addition to providing information on the content of the specific folate vitamins, the method includes a rapid extraction of folates from food, which can be performed within 8 hours. The method has been successfully validated in a collaborative study for strawberry, spinach, lentils, yoghurt, liver, and infant formula. The method replaces Method 111 “Folate, biologically active. Microbiological determination in milk and milk products with Lactobacillus casei” which was discontinued year 2020.
- Ložnjak Švarc, P., Oveland, E., Strandler, H. S., Kariluoto, S., Campos-Giménez, E., Ivarsen, E., Malaviole, I., Motta, C., Rychlik, M., Striegel, L. & Jakobsen, J., 2020, Collaborative study – Quantification of total folate in food using an efficient single-enzyme extraction combined with LC-MS/MS Food Chemistry. 333, 10 p., 127447.
- Ložnjak, P., Striegel, L., Díaz De la Garza, R. I., Rychlik, M. & Jakobsen, J. (2020) Quantification of folate in food using deconjugase of plant origin combined with LC-MS/MS: A method comparison of a large and diverse sample set, Food Chemistry. 305, 10 p., 125450.
- Ložnjak P., García-Salinas, C., Díaz de la Garza, R. I., Bysted, A. & Jakobsen, J., (2019) The use of a plant enzyme for rapid and sensitive analysis of naturally-occurring folates in food by liquid chromatography-tandem mass spectrometry, Journal of Chromatography A. 1594, p. 34-44.