Vitamin B1, vitamin B2 and vitamin B6 are water-soluble vitamins which play role in various biological activities. Vitamin B2 is not only a cofactor for reduction-oxidation enzymes in energy metabolism but also acts as a coenzyme for the metabolism of folate, Vitamin B12, Vitamin B6 and homocysteine. Vitamin B1 plays a major role in obtaining energy from carbohydrates and fat. Thiamine pyrophosphate (TPP) which is an active form of vitamin B takes role as coenzyme for some enzymatic reactions in carbohydrate metabolism and pyruvate decarboxylase. In addition, TPP is significantly involved in the oxidative degredation of glucose. Vitamin B6 is taken by food, and underwent with some enzymatic transformation to pyridoxal-5-phosphate which is the active form of it. Pyridoxal-5- phosphate participates in nearly a hundred different enzymatic processes, as a cofactor in amino acid metabolism and in the production of hemoglobine or neurotransmitters in the brain. JASEM LC-MS/MS analysis kit provides simultaneous quantification of B1, B2, B6, pyridoxal-5-phosphate, FAD and TPP in whole blood.