Lipophilic vitamins detection

Lipophilic vitamins A, D2, and E (a-tocopherol) (Rp values 0.34, 0.44, and 0.62, respectively) are separated on silica gel plates and a mixture of benzene-chloroform-acetone (88.5 8.8 2.7, by volume) applied [8]. Table 1 gives information about detection and the hRp values of Upohilic vitamins in mixtures, using the various layers and solvents. 

Table 1 hRp Values of Lipophilic Vitamins Using Various Separation Systems and Detection of Lipophilic Vitamins... 

Generally, TLC is useful for the investigation of a wide range of lipophilic vitamin applications, i.e., purification of samples, qualitative detection, quantitative determination, and the use of new visualizing agents, and also for separation of some optical isomers. ... 

Densitometrical analysis is the most important method of detection of organic compounds including lipophilic vitamins, fork et al. investigated vitamin D3 and o-a-tocopherol on HPTLC Kieselgel 60 (Merck) plates using cyclohexane-diethylether (40 20, v/v) and toluene-chloroform (10 10, v/v), respectively. Fluorescence scan of a chromatogram track with 50 ng vitamin D3 per... 

Lipophilic vitamins, 1055-1077 vitamin A, 1056-1060 detection, 1059-1060 quantification, 1060 sorbents, 1056-1059 vitamin D, 1060-1066 detection, 1065 quantification, 1065 sorbents, 1063-1065 vitamin E, 1066-1071 detection, 1069-1070 quantification, 1070 sorbents, 1067-1069 vitamin K, 1071-1074 detection, 1074 quantification, 1074 sorbents, 1071-1074... 

After hydrolysis of triglycerides, denaturation (ethanol) and extraction (hexane) of milk samples are similar to those procedures used in preparation of plasma samples. EHie to high concentrations of coextracted lipophilic compounds, a semipreparative HPLC cleanup step often is used in these preparations. Indyk et al. (92) and Lambert et al. (99) used adsorption HPLC and hexane/isopropanol mixtures for cleanup and a reversed-phase HPLC for detection, whereas Isshiki et al. (94) used a Cig reversed-phase system with a methanol/acetonitrile mixture for cleanup and a C2 or C3 reversed phase for detection. Canfield et al. (95,96) worked with two open-column chromatography systems (silica) to isolate vitamin K compounds prior to HPLC detection, whereas Schneiderman et al. (98) introduced a completely different method for isolation of these compounds. They used supercritical fluid extraction (SFE) with CO2 as solvent to determine VKl in powdered infant formulas. Details of this particular method will be discussed later in this chapter. 

Several comprehensive reviews have been published on the existing chromatographic methods for the analysis of lipophilic antioxidants (tocopherols, tocotrienols, and carotenoids) in various sample matrices (Abidi, 2000 Aust et al., 2001) on electrochemical approaches in the sensing of natural or biological antioxidants and antioxidant capacity (mainly polyphenols and vitamins C and E) using cyclic voltammetry on flow injection analysis (FIA) with amperometric detection in food and biological samples (Blasco et al., 2007) and on chemiluminescence (CL) and fluorescence (FL) methods for the analysis of oxidative stability, antioxidant activity, and lipid hydroperoxide content in edible oils (Christodouleas et al., 2012). 

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