Amylose with 2-propanol

Lipid-complexed amylose chains interfere with amylose-iodine (If and If) complex formation. Therefore, extraction of complexed lipids with 75% n-propanol is necessary prior to determination of total amylose content. 

FIGURE 12 Chromatograms of enantiomeric resolution of nebivolol on amylose carbamate CSPs. (a)-(c) Chiralpak AD with (a) ethanol, (b) 1-propanol, and (c) 2-propanol, (d, e) Chiralpak AD-RH with (d) ethanol and (e) 1-propanol, separately, as the mobile phase. (From Ref. 63.)... 

The energies of interaction of ethanol and 2-propanol with amylose tris(3,5-dimethylphenylcarbamate) phases were calculated. The energies of interaction of ethanol, 2-propanol, and their mixtures in different ratios are calculated and presented in Table 3. The energy of interaction G and the energy factor (for ethanol and 2-propanol) F are calculated by the following equations [63]. 

Balmer et al. [60] separated the two enantiomers of omeprazole on three different stationary phases with immobilized protein, viz, Chiral-AGP with a-1 acid glycoprotein, Ultron ES-OVM with ovomucoid, and BSA-DSC with BSA cross-linked into 3-aminopropyl silica using N-suc-cinimidyl carbonate. The mobile phase (1 ml/min) was phosphate buffer solution with 3—10% 2-propanol as the organic modifier. The enantiomers of omeprazole were separated on Chiralpak AD, an amylose-based chiral stationary phase, with ethanol-hexane (1 4) as mobile phase (1 ml/min). 

The high lipid content of oat starch is reflected in the high value of the transition enthalpy (AHCX) measured for the amylose-lipid complex (Table 15.4). This transition is reversible, and on a rerun greater AHCX, as well as Tcx (endotherm peak temperature), was found.26 When the oat starch was defatted, the endotherm assigned to the amylose-lipid complex disappeared from the DSC thermogram.26 Extraction at room temperature with 1-propanol water (3 lv/v) did not influence the thermogram of the starch, but if the starch was refluxed in the same solvent, a decrease in AH and a complete elimination of the endotherm ascribed to the amylose-lipid complex occurred.28 For oat starches with a lipid content of 1.1-1.7%, it was possible to... 

Type V includes chiral stationary phases based on immobilized proteins as well as polysaccharide phases such as cellulose and amylose carbamate. They are used in conjunction with aqueous buffered mobile phases. The interaction between the stationary phase and the analytes is based on hydrophobic interaction as well as electrostatic interaction in the case of proteins. The retention of the analytes can be controlled by the addition of organic modifiers such methanol, ethanol, and 2-propanol. 

Simultaneous direct determination of the enantiomers of verapamil and norverapamil in plasma using a derivatized amylose HPLC chiral stationary phase" (53). An AD CSP was used to determine the plasma concentrations of the enantiomers of verapamil and its major metabolite norverapamil. After a liquid-liquid extraction, the analytes were resolved on the amylose column using a mobile phase composed of heptane 2-propanol ethanol, (85 7.5 7.5, v/v/v) modified with 1.0% tri-ethylamine, a flow rate of 1.0 mL/min, and a column temperature of 30 C. The assay was validated for use in human pharmacoldnetic studies. A representative chromatogram is presented in Fig. 5. 

Many other amylose complexes are water-insoluble, and the complexes with methanol, 1-propanol, acetone, and butanone may be precipitated from solutions of amylose in methyl sulfoxide, as well as from aqueous solution. As amylose frequently forms crystalline complexes. X-ray diffraction patterns have been obtained for a number of them. Amylose-methyl sulfoxide complexes have a structure almost identical to those of amylose-ethylenediamine complexes, in which the complexing ratio is one ethylenediamine molecule per two n-glucose residues. The helix packing-diameter of the complexes, at least for complexes with linear aliphatic ketones, is dependent upon the chain-length of the molecule complexed, although other factors are also involved. ... 

Tetramethrin Tetramethrin has four isomers (2 = 4). Base line separation of these four isomers was achieved by Zhe et al. (2008) by their use of a Qiiralpak AD-H column (amylose 3,5-dimethylpheny 1-carbamate) and a solvent system consisting of n-hexane ethanol 2-propanol (99.0 0.9 0.1, v/v/v) (Table C14, Appendix C). The column was purchased from Daicel Chemical Industries Ltd., Japan. The isomers elute in the order of B, D, A, and C, respectively. The trans isomers (D and A) yielded the largest peaks, because the sample of tetramethrin used was frans-isomer enriched. Zhe et al. (2008) used a UV detector in conjunction with a polarimeter to identify the isomers. According to Kurihara et al. (1997a, b), aU of the IR isomers give positive (+) peaks in the polarimeter. 

Polysaccharides, the most abundant biopolymers in nature, have also been used in chromatography as CS. Although intrinsically chiral, the materials used for this purpose are polysaccharide derivatives. Among them, esters and carbamates of cellulose and carbamates of amylose, in particular the 3,5-dunethylphenylcarbamates of either of them, are the most popular. When the CSPs are constituted by a silica gel matrix onto which the CS is simply coated, the composition of the mobile phase is limited to those solvents that do not solubilize the polysaccharide derivative. Mixtures of a hydrocarbon, hexane, or heptane, with an alcohol, usually 2-propanol, methanol, or ethanol, are common mobile phases. Although aqueous mobile phases can be used together with acetonitrile or methanol, these conditions tend to provide lower enantioselectivity values. ... 

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