Determination of the amount of melatonin in foodsupplements by HPLC

Melatonin is a hormone produced in the pineal gland that regulates various physiological functions in the human body and has the ability to scavenge and suppress free radicals. Because melatonin plays an important role in regulating circadian rhythm, it is considered a critical molecule in the diagnosis and treatment of various diseases. In clinical practice, various forms of preparations are used for treatment and supplementation purposes in the form of exogenous melatonin application. It is important to accurately determine the melatonin content of the preparations to determine the appropriate dose and quality control in treatments. In this study, a novel, inexpensive, fast and robust HPLC-PDA method was developed and validated for the detection of melatonin in various preparations. The separation process was carried out isocratically on a Nanologica SVEA C18 (4.6 x 250 mm, 5 µm) column, and the composition of the mobile phase consisted of Water : ACN:(30:70, v/v). The flow rate was 1.00 mL min-1 , the column oven temperature was 25 °C and the injection volume was 10 µL. In the developed HPLC-PDA method, 0.14 mg L-1 LOD and 0.46 mg L-1 LOQ values were obtained. It was observed that recovery values varied between 98,15-102,02%. The %BSS values of the developed method are below 1%. It has been shown that the developed HPLC-PDA method can be used in routine analyzes for the determination of melatonin in various preparations.