Kinetics of glucose mutarotation assessed by an equal-amplitude paired polarized heterodyne polarimeter.
A dual-frequency equal-amplitude paired polarization heterodyne polarimeter (DEPHP) was set up in order to precisely measure the mutarotation rate constants of D-glucose in tridistilled water. The DEPHP is based on a balanced detector detection scheme for measurement of the optical rotation angle of D-glucose/water solution during the conversion process between alpha-D-glucose and beta-D-glucose while in a nonequilibrium state. The DEPHP can perform shot-noise-limited detection, so that the total optical rotation angle together with the mutarotation rate constants of alpha-D-glucose and beta-D-glucose conversion can be measured with high sensitivity. In this experiment, the sensitivity of the optical rotation angle measurement was 8.3 x 10(-5) deg/cm, while the total (k), forward (k(1)) and reverse (k(2)) mutarotation rate constants of D-glucose were found to be k = 7.67 x 10(-5) s(-1), k(1) = 2.76 x 10(-5) s(-1), and k(2) = 4.91 x 10(-5) s(-1), respectively, in tridistilled water. Moreover, using the DEPHP, we can measure the specific rotation angles of alpha-D-glucose and beta-D-glucose in water at 632.8 nm. They were 105 degrees and 12 degrees, respectively. Finally, the detection sensitivity of the DEPHP system is also discussed.
Lin
Chu-En
CE
Department of Optics and Photonics, National Central University, Jhongli, Taiwan 320.
Yu
Chih-Jen
CJ
Chen
Chuan-Lin
CL
Chou
Li-Dek
LD
Chou
Chien
C
D005947:Glucose / Q000737:chemistry*; D007700:Kinetics; D009904:Optical Rotation; D015203:Reproducibility of Results; D014867:Water / Q000737:chemistry*
D014867:Water; D005947:Glucose