Example Chromatography

A solution of the substrate (1 mmol of 1-naphthol or 5-hydroxyisoquinoline or 8-aminoquinoline, etc.) in acetonitrile-water (2 1, v/v) was added dropwise to a solution of BTI (946 mg, 2.2 mmol) in the same solvent system under nitrogen at 0°C. The mixture was stirred for 2 h and, after evaporation of volatiles, the quinones were obtained in crude form and purified by column chromatography. Examples of such quinones are collected in Table 4.2. 

Normal-Phase Chromatography Example. Vitamin E, an antioxidant, is a complex made up of tocopherols and tocotrienols (Figure 8-62), which are sometimes used to stabilize formulations. Tocopherols are a series of related benzopyranols with a C16 saturated side chain. Tocotrienols contain three double bonds on the C16 side chain [32]. 

Thio-substituted carbenes which are generated from a chloromethyl sulfide and t-BuOK reacted with enamines 147 to give aminocyclopropanes 148 and 149254-256 (equation 36). In some cases, both isomers could be separated by chromatography (examples are given in equation 36)2 . ... 

Anion exchangers such as the IonPac AS5 are also suited for the analysis of com-plexed transition metals and heavy metals, which opens another field of application for ion chromatography. Examples of respective chromatograms for the separation of metal-EDTA complexes as well as for metal-chloro complexes are displayed in Figs. 3-78 and 3-79. 

The general application of reverse-phase HPLC can be employed directly in the separation and quantitation of total lipid classes. However, the high degree of resolution possible from HPLC columns is more frequently employed for the separation and analysis of individual lipid components from complex mixtures or individual lipid classes previously separated by other chromatographic procedures (e.g., column chromatography). Examples include HPLC analysis of acylglycerols (Plattner, 1981 Kuksis, 1994) and phospholipids (Porter and Weenen, 1981). 

One unique development in relation to electrospray is paperspray, a soft ionization method in which the sample is ionized into the IMS in an nncomplicated manner without the need for a pump or capillary. The advantage is that an analyte can be ionized directly from filter paper containing the sample or after separation by paper chromatography. Examples of the nse of paperspray-lMS inclnde chlorpromazine, reserpine, and 2,6 Di-t-butylpyridine. 

---