title: Second derivative synchronous fluorimetric method for simultaneous determination of harman and norharman in coffee samples.
abstract: The simultaneous determination of harman and norharman using second derivative synchronous fluorescence method has been developed based on their natural fluorescence. Due to their similar molecular structures, it is difficult to determine them simultaneously in the mixture using conventional fluorimetry. Overlapping of fluorescence spectra was resolved by using a constant second derivative synchronous fluorimetry. The derivative synchronous spectrum, maintaining a constant difference of Δλ=150 nm between emission and excitation for both the compounds, has been selected for the analysis. The range of application is between 0.182 and 18.2 μg/mL (correlation coefficient, R=0.9982) for harman and between 0.504 and 16.8 μg/mL (correlation coefficient, R=0.9962) for norharman. The recovery ranges of 98.5-101.1% for harman and 97.5-99.1% for norharman from their synthetic mixture was reported. The detection limits are 0.016 μg/mL and 0.038 μg/mL for harman and norharman, respectively. Similarly, the quantitation limit of the two compounds was found to be 0.049 and 0.109 μg/mL, respectively. The method was applied to the simultaneous determination of both compounds in coffee samples with satisfactory results.
authors.affiliation: Advanced Materials Research Chair, Department of Chemistry, College of Science, King Saud University, P.O. Box-2455, Riyadh 11451, Saudi Arabia. swabaidur@ksu.edu.sa
authors.forename: Saikh Mohammad
authors.initials: SM
authors.lastname: Wabaidur
authors.forename: Sang Hak
authors.initials: SH
authors.lastname: Lee
authors.forename: Zeid Abdullah
authors.initials: ZA
authors.lastname: Alothman
authors.forename: Masoom Raza
authors.initials: MR
authors.lastname: Siddiqui
authors.forename: Seikh Mafiz
authors.initials: SM
authors.lastname: Alam
mesh_terms: D002243:Carbolines; D003069:Coffee / Q000737:chemistry*; D006247:Harmine / Q000031:analogs & derivatives* / Q000032:analysis; D057230:Limit of Detection; D009498:Neurotoxins / Q000032:analysis*; D013050:Spectrometry, Fluorescence / Q000379:methods*
chemical_list: D002243:Carbolines; D003069:Coffee; D009498:Neurotoxins; D006247:Harmine; C005010:harman; C010262:norharman