Abstract: Since the intermediates in the manufacturing of Vitamine K_1 exhibit UV absorption,they interfere with its assay by UV spectrophotometric methods. These intermediates can be removed by column chromatography with A1_2 O_3 ocitaiuing 7% H_2O. The UV absorption curve of these intermediates was determined. The effects of differentwater content of A1_2 O_3 on K_1 and its intermediates were investigated, and the behavior of absorption among these intermediates on A1_2 O_3 containing 7 % H_2 O was also discussed.