D,L-Phenylalanine anilide

For chromatographic purposes the polymers were first milled, then sieved in a wind-sieving machine (Alpine Multiplex 1(X) MZR). Separation factor a for the separation of D,L-phenylalanine anilide was 3.5. The chromatographic separation showed a resolution... 

The polymer thus obtained was gel-like, with an inner surface area of 3.8 m g . Swelling in acetonitrile was 2.01. For chromatographic separations the performance was improved by dry heating of the sorbent for 17 h at 120 °C. The a value for the separation of D,L-phenylalanine anilide was 2.3 chromatographic separation showed a resolution for the racemate of / = 1.9. 

MIP assays can also be utilized in synthetic organic applications. For example, MIP-based assays have been used to measure the chiral purity of samples in organic solvents. An L-phenylalanine anilide (l-PAA) imprinted polymer was utilized as a recognition element to measure the enantiomeric excess (ee) of PAA samples (Chen and Shimizu 2002). The MIP displays greater capacity for l-PAA versus d-PAA samples of similar concentration, and this difference was used to estimate enantiomeric excess. The enantiomeric excess of an unknown solution was determined by comparing the UV absorbance of the PAA remaining in solution after equilibration against a calibration curve. This MIP assay was demonstrated to be rapid and accurate with a standard error of +5% ee. 

Chen YB, Kele M, Sajonz P, Sellergren B, Guiochon G. Influence of thermal annealing on the thermodynamic and mass transfer kinetic properties of D- and L-phenylalanine anilide on imprinted polymeric stationary phases. Anal Chem 1999 71 928-938. 

Fig. 4,3. Differences in the effect of temperature on the number of theoretical plates and of the amount of chromatographed substance on the retention of template molecules and their enantiomers, (a) Temperature dependence of the number of theoretical plate Wh) in the resolution of D-la and L-la on a polymer imprinted with 1 [21]. (b) Dependence of the capacity factor k on the amount of chromatographed substance in the resolution of l- and of D-phenylalanine anilide on a polymer imprinted with L-phenylalanine anilide [49],...

Fig. 16.7. CEC-separation of D,L-phenylalanine on a column containing imprints of L-phe-nylalanine anilide. This demonstrates the interesting strategy of using a structurally similar compound to the analyte as the imprint molecule for the MIP preparation. Due to their low solubility in the pre-polymerisation mixture, amino acids are normally not amenable to non-covalent imprinting. Reprinted from [69] Copyright (1997), with permission from Elsevier Science,...

Figure 13 Separation of D,L-phenylalanine with an capillary equipped with an MIP monolith imprinted against L-phenylalanine anilide. Mobile phase 70 20 10 ACN/HAC/H2O (v/v). CEC capillary 50 cm x 75 pm ID, effective length 25 cm. Electroinjection 5 s, 10 kV. Separation 400Vcm Detection 254nm. (From Ref. 23.)...

Andersson et al. (105) prepared a polymer using ethylene glycol dimethacrylate as across linker, methacrylic acid as monomer and D- or L-phenylalanine anilide as the print molecule. The chromatographic data on the separation of D- and L-phenylalanine anilide is shown in Table 4. 

Table 4 TLC Separation of D- or L- Phenylalanine Anilide on TLC Plates containing a Stationary Phase Based on Imprinted Polymer...

L-phenylalanine anilide 10 (L) 35 (D) 4.86 0.9 Plates were dried, sprayed with... 

Preparation of Synthetic Polymers Imprinted with L- or D-Phenylalanine Anilide... 

An opposite behavior was shown from L- and D-enantiomers of phenylalanine anilide on L- and o-Phe-An MIP plates. Elution time was 7 min. Although very high a-values were obtained, the resolution between the two enantiomers on both MIPS was low, because very elongated spots were obtained, independently on their... 

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