[Determination of enantiomeric purity for lactic acid in fermentation broth by Rhizopus oryzae with high performance liquid chromatography].
A procedure for the resolution of DL-lactic acid and the determination of D-isomer ratio in L-lactic acid fermentation broth by Rhizopus oryzae is described. The effects of pH of mobile phase and concentration of chiral mobile phase additives on resolution of DL-lactic acid were investigated. The optical isomers of lactic acid were resolved by RP-HPLC with 2,3,6-tri-O-beta-cyclodextrin(TM-beta-CD) as a chiral mobile phase additive, and C18 column as stationary phase, and detected at wavelength 210 nm. The results showed that a correction factor should be introduced into the equation for calculation of the percentage of D-lactic acid, because the UV absorption of D-lactic acid and L-lactic acid might not be the same when TM-beta-CD was present. Quantitation was achieved with external standard method, the average recovery was 100.4%, and the relative standard deviation was 0.82%. This method can be used for the determination of the percentage of D-isomer in L-lactic acid fermentation broth by Rhizopus oryzae, and it is simple, rapid and accurate. The results showed that the mass fraction of D-isomer in the fermented broth increased during the period of storage.
Bai
D M
DM
Department of Biochemical Engineering, School of Chemical Engineering & Technology, Tianjin University, Tianjin 300072, China.
Zhao
X M
XM
Hu
Z D
ZD
D002851:Chromatography, High Pressure Liquid / Q000379:methods; D005285:Fermentation; D007536:Isomerism; D019344:Lactic Acid / Q000032:analysis* / Q000737:chemistry; D012233:Rhizopus
D019344:Lactic Acid