Analysis of the Optical Isomer of Ethyl (R)-(−)-4-Cyano-3-hydroxybutyratic Acid by Pre-column Derivatization Gas Chromatography

OBJECTIVE  To establish a pre-column derivatization gas chromatography method for detection of ethyl (R)-(−)-4-cyano-3-hydroxybutyratic acid(ATS-5) isomer.

METHODS The concentration of ATS-5 in anhydride aceic acid was 30 mg·mL⁻¹, Amberlyst-15 was added to derivatization; the Supelco Beta DEX 325(30 m×0.25 mm, 0.25 μm) was used; the detector was FID.

RESULTS The resolution between ATS-5 and isomer was 4.1; the quantitation limit of ATS-5 isomer was 15 μg·mL⁻¹; the liner for ATS-5 isomer in the rang of 15−225 μg·mL⁻¹(Y=0.2395X+0.2516, r=1.0000) was good; the RSD of repeatability was 2.2%(n=6); the RSD of intermediate precision was 2.6%(n=12); the recovery was 101.4%−108.9%; the sample solution was stable at room temperature for 3 d.

CONCLUSION This method is simple, specificity, accurate and reproducible, which can detect isomer in ethy ATS-5.