欧美xingq一区二区,av中文在线资源库,国模私拍一区二区国模曼安,免费在线看污片

SUPELCO Astec CHIRALDEX A-TA手性氣相色譜柱 毛細(xì)管柱
 

• CD Type: α (alpha)
• Derivative: Trifluoroacetyl
• Temp. Limits: -10 °C to 180 °C (isothermal or programmed)

    Incorporates a phase consisting of a 2,6-di-O-pentyl-3-trifluoroacetyl derivative of α-cyclodextrin.

    Trifluoroacetylation of the 3 position hydroxyl groups after pentylation of the 2,6 hydroxyl groups creates a phase with high selectivity for oxygen containing analytes in the form of alcohols, ketones, acids, aldehydes, lactones, and halogenated compounds.

Features: 

• Separates the widest variety of enantiomers
• Separates the greatest number of enantiomers
• Gamma more selective than beta form
• Unique retention behavior
• Extraordinary versatility and chiral selectivity

Analytes:

Useful for homologous series of:

• Amino acids (primary, secondary, aromatic and aliphatic)
• Amines (primary, secondary, cyclic, aromatic and halogenated)
• Amino alcohols
• Alkanes, hydrogenated alkanes
• Alcohols (aliphatic and aromatic)
• Acids (halogenated and hydroxy)
• Esters (aromatic, aliphatic, hydroxy, di-ester)
• DiolsLactonesKetones
• Phthalides
• Sulfoxides

Mechanism Observations:

• Strong dipole-dipole interactions
• Longer alkyl chain; greater retention; increase in enantioselectivity up to C4/C5
• Halogens known to favor cavity interaction

   Dipole-dipole interactions are commonly identified in the mechanism of separation for TA phases. In a homologous series of alkane enantiomers, identical alpha values are observed regardless of chain length or branching indicating only 1 or 2 carbons may be contributing to chiral recognition. Alpha values are greatly affected by size and polarity of the head group. Functional groups like epoxides, amino alcohols and alcohols can dictate the cyclodextrin selection. Aldehydes, carboxylic acids and epoxides separate better on the gamma while alcohols, alcohol amines and other linear molecules separate better on the beta derivative.

SUPELCO Astec CHIRALDEX A-TA手性氣相色譜柱 毛細(xì)管柱 訂貨信息：