Determination of nicotinamide (vitamin B3) in cosmetic products using differential spectrophotometry and liquid chromatography (HPLC)

Differential spectrophotometry and liquid chromatography (TLC, HPLC) were used to qualitative and quantitative determination of nicotinamide (vitamin B-3) in commercial cosmetics creams. The liquid-liquid extraction has been used as pretreatment processes for cosmetics samples prior to their analyses. Differential spectra were collected using a UV-Vis spectrophotometer with the range of 220-350 nm, in a 1-cm layer, with the speed of spectrum registering at 240 nm/min, the spectra width of the radiation leaving the monochromator of 1.00 nm and the increase in wavelength of 1 nm. The measuring methods of peak-zero and peak-peak were used. The reversed-phase determination of vitamin B-3 was conducted on a LiChrospher 100 RP-18 column (250 x 4 mm, 10 mu m) at 260 nm, using a mixture of KH2PO4 (0.02 M)-methanol (9: 1) as a mobile phase (the flow rate - 1.5 mL/min). The UV method (D-2) for the determination of vitamin B-3 in cosmetic products is accurate with the comparison of reference method of HPLC.