Biomaterial Database

A validated liquid chromatographic method for determining folates in vegetables, milk powder, liver, and flour. 1999

E J Konings

Inspectorate for Health Protection, Commodities and Veterinary Public Health, Maastricht, The Netherlands. Erik.Konings@wxs.nl

A liquid chromatographic (LC) method was elaborated for determining folates in foods. Folates were extracted by homogenizing in buffer and heat treatment. A portion was incubated with an enzyme preparation containing conjugase, amylase, and protease. After purification by affinity chromatography, folate monoglutamates were determined by reversed-phase LC with fluorescence and diode array detection. Gradient elution with phosphate buffer and acetonitrile was used to separate vitamers. The most abundant folate forms naturally present in foods were detected, including tetrahydrofolic acid, 5-methyltetrahydrofolic acid, and 5-formyltetrahydrofolic acid. 10-Formylfolic acid could be detected by applying a second fluorescence detector. Folic acid, used for fortification, might also be quantitated with this system. The difference between folate concentrations in sample extracts, with and without treatment of conjugase, is a measure of the quantity of polyglutamates in the food matrixes. An additional treatment with conjugase, amylase, and protease reflects the amount of matrix-bound folates. The LC system gave a linear response over the range 0-100 ng/mL. Detection limit for these compounds were 7 pg/mL for tetrahydrofolic acid and 5-methyltetrahydrofolic acid and 59 pg/mL for 10-formylfolic acid (signal-to-noise ratio > or = 3) when 100 microL was injected. Detection limits for 5-formyltetrahydrofolic acid and folic acid were 1 ng/mL. Repeatability relative standard deviation values for separate folates in 3 candidate Certified Reference Materials (CRMs)--mixed vegetables (CRM 485), pig liver (CRM 487), and whole-meal flour (CRM 121)--and a Certified Reference Material milk powder (CRM 421) varied from 3.3 to 21.0% for the concentration range 1.8-1440 micrograms/100 g. Recoveries ranged from 73 to 109%. Use of amylase and protease was advantageous. Use of a commercially available folate-binding protein for cleanup saved time and money and was effective. Results for 5-methyltetrahydrofolic acid were in good agreement with results obtained with other LC methods. Results for total folates were lower than results obtained with microbiological methods.

UI	MeSH Term	Description	Entries
D008099	Liver	A large lobed glandular organ in the abdomen of vertebrates that is responsible for detoxification, metabolism, synthesis and storage of various substances.	Livers
D008892	Milk	The off-white liquid secreted by the mammary glands of humans and other mammals. It contains proteins, sugar, lipids, vitamins, and minerals.	Cow Milk,Cow's Milk,Milk, Cow,Milk, Cow's
D002846	Chromatography, Affinity	A chromatographic technique that utilizes the ability of biological molecules, often ANTIBODIES, to bind to certain ligands specifically and reversibly. It is used in protein biochemistry. (McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)	Chromatography, Bioaffinity,Immunochromatography,Affinity Chromatography,Bioaffinity Chromatography
D002853	Chromatography, Liquid	Chromatographic techniques in which the mobile phase is a liquid.	Liquid Chromatography
D005433	Flour	A powdery meal obtained from ground up starchy foodstuff, such as seeds of WHEAT; RICE and other EDIBLE GRAIN; LEGUMES; and NUTS; or ground up PLANT TUBERS.	Almond Flour,Almond Meal,Corn Flour,Corn Meal,Grain Flour,Grain Meal,Nut Flour,Potato Flour,Rice Flour,Rice Meal,Soybean Flour,Soybean Meal,Wheat Flour,Wheat Meal,Semolina Flour,Almond Flours,Almond Meals,Corn Flours,Corn Meals,Flour, Almond,Flour, Corn,Flour, Grain,Flour, Nut,Flour, Potato,Flour, Rice,Flour, Semolina,Flour, Soybean,Flour, Wheat,Flours,Flours, Almond,Flours, Corn,Flours, Grain,Flours, Nut,Flours, Potato,Flours, Rice,Flours, Semolina,Flours, Soybean,Flours, Wheat,Grain Flours,Grain Meals,Meal, Almond,Meal, Corn,Meal, Grain,Meal, Rice,Meal, Soybean,Meal, Wheat,Meals, Almond,Meals, Corn,Meals, Grain,Meals, Rice,Meals, Soybean,Meals, Wheat,Nut Flours,Potato Flours,Rice Flours,Rice Meals,Semolina Flours,Soybean Flours,Soybean Meals,Wheat Flours,Wheat Meals
D005492	Folic Acid	A member of the vitamin B family that stimulates the hematopoietic system. It is present in the liver and kidney and is found in mushrooms, spinach, yeast, green leaves, and grasses (POACEAE). Folic acid is used in the treatment and prevention of folate deficiencies and megaloblastic anemia.	Pteroylglutamic Acid,Vitamin M,Folacin,Folate,Folic Acid, (D)-Isomer,Folic Acid, (DL)-Isomer,Folic Acid, Calcium Salt (1:1),Folic Acid, Monopotassium Salt,Folic Acid, Monosodium Salt,Folic Acid, Potassium Salt,Folic Acid, Sodium Salt,Folvite,Vitamin B9,B9, Vitamin
D005504	Food Analysis	Measurement and evaluation of the components of substances to be taken as FOOD.	Analysis, Food,Analyses, Food,Food Analyses
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D013050	Spectrometry, Fluorescence	Measurement of the intensity and quality of fluorescence.	Fluorescence Spectrophotometry,Fluorescence Spectroscopy,Spectrofluorometry,Fluorescence Spectrometry,Spectrophotometry, Fluorescence,Spectroscopy, Fluorescence
D013552	Swine	Any of various animals that constitute the family Suidae and comprise stout-bodied, short-legged omnivorous mammals with thick skin, usually covered with coarse bristles, a rather long mobile snout, and small tail. Included are the genera Babyrousa, Phacochoerus (wart hogs), and Sus, the latter containing the domestic pig (see SUS SCROFA).	Phacochoerus,Pigs,Suidae,Warthogs,Wart Hogs,Hog, Wart,Hogs, Wart,Wart Hog