Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7642852 | Microchemical Journal | 2014 | 5 Pages |
Abstract
Silica, C8 and C18 monolithic column were the only option for separation on a sequential injection chromatography (SIC) system due its low-pressure operation. Therewith, the separation of molecules poorly retained by this stationary phase was a difficult task. This work presents the first use of micellar chromatography on a SIC system, with the applicability demonstrated by the determination of melamine in milk. The mobile phase was composed by aqueous sodium dodecyl sulfate (SDS) solution and propanol (92.5:7.5). The adsorption of SDS monomers on the C18 stationary phase modified its chromatographic properties, enabling satisfactory melamine separation from the milk components. The sample pretreatment procedure was on-line implemented by dilution of the sample with SDS using a multiposition valve. Calibration equations obtained from melamine solutions prepared in different types of milk and water presented similar sensitivity, indicating absence of matrix effects. A linear response was observed within 2.0 and 6.0 mg Lâ 1 of melamine with a detection limit estimated at 0.6 mg Lâ 1 and coefficients of variation at 2.9% (n = 6). The procedure was suitable for fast determination of melamine below the limits established by FDA and WHO (2.5 mg Lâ 1), with minimized reagent consumption. Results for different milk samples agreed with those obtained by high performance liquid chromatography at the 95% confidence level.
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
Alex D. Batista, Carina F. Nascimento, Wanessa R. Melchert, Fábio R.P. Rocha,