[Folic Acid Reference Standard (Control 921) of National Institute of Health Sciences].

Folic acid was tested for the preparation of "Folic Acid Reference Standard (Control 921)". The quality of the raw material was examined and compared with the previous Folic Acid Reference Standard (Control 862). Analytical data obtained were as follows: water content, 7.52%; free amines, 0.1%; infrared spectrum, the same as that of the JP Reference Standard; thin-layer chromatography, three impurities were detected; high-performance liquid chromatography (HPLC), two impurities were detected; assay, 101.2% by spectrophotometry at 550 nm and 100.4% by HPLC. Based on the above results, the raw material was authorized as the Japanese Pharmacopoeia Reference Standard (Control 921).