Melatonin In Samples Research Articles

Geographical characterization of South America wines based on their phenolic and melatonin composition: An exploratory analysis

This study aimed to determine ellagic acid, vanillic acid, syringic acid, quercetin, and melatonin in samples of wines from Brazil, the São Francisco Valley region, and Argentine region (Valle de Uco, Luján de Cuyo, Mendoza and Neuquén). The phenolic compounds and melatonin were determined by UHPLC MS/MS and HPLC. Quercetin was the compound found in major quantities in Argentine wines. In some bottles of Brazilian wines, vanillic acid and ellagic acid were found in higher bottles compared to Argentine wines. As for syringic acid, as selected filters in Brazilian wines, they were inferior in Argentine wines samples. PCA and HCA were carried out to group the data obtained according to the region of origin of the wines.

Rhodamine B - as New Chromophore for the Determination of Melatonin in Biological, Food, and Pharmaceutical Samples.

Melatonin is an essential biomarker for sleep-related disorders. Reliable methods of analysis are needed for melatonin. Therefore, a new chromophore (Rhodamine B) was proposed for the assay of melatonin; this method succeeded to enlarge the working concentration range and to decrease the limit of determination comparing with the method that just used the native fluorescence of melatonin. Rhodamine B was proposed as a new chromophore for the assay of melatonin in biological, food, and pharmaceutical samples. Fluorescence was used for the determination of melatonin. The results obtained using Rhodamine B were compared with those obtained by the native fluorescence of melatonin. Using the new chromophore, melatonin was determined in the concentration range between 0.01 and 50 pmol L-1, with the detection limit of 2.4 fmol L-1. The recovery of melatonin was higher than 98.00% with a relative standard deviation of less than 0.10%, when the method was applied for the assay of melatonin in samples such as breast milk, whole blood, milk powder, and pharmaceutical formulations. Utilization of Rhodamine B enlarged the linear concentration range for the assay of melatonin and decreased the detection limit, making possible the assay of melatonin in a variety of samples such as pharmaceuticals, food, and biological samples.