The electrochemical behavior of trifluoperazine at decanethiol self\|assembled monolayer (SAM) modified gold electrodes (i.e. C 10 H 21 SH/Au) has been studied. Trifluoperazine can effectively accumulate on C 10 H 21 SH/Au electrodes and generate a sensitive anodic peak at about 0.63 V (vs. SCE) in 0.05 mol/L pH 9.4 Na 2B 4O 7 buffer solution. Under the selected conditions, the anodic peak current was linear to trifluoperazine concentration in the range of 5.0×10 -7 \|3.0×10 -5 mol/L with correlation coefficient of 0.997, the detection limit was 3.0×10 -8 mol/L. This method was applied to the determination of trifluoperazine in drug samples and the recovery was 97.3%\|104.0%. It was found that sodium dodecyl sulfate (SDS) could make the anodic peak current increase. In the presence of SDS, the peak at about 0.63 V turned into two peaks, resulting from the change of the electrochemical mechanism.
The separation of a group of 17 purine and its derivatives by capillary zone electrophoresis is presented. A systematic approach was used to study the effect of pH, buff-er type, organic modifiers, applied potential, sodium dodecyl sulfate (SDS) and cyclodextrins on the separation of these pu-rine derivatives. An ideal condition was found for their se-paration, which was 30 mmol/L sodium borate buffer (pH 9-9.5), 10% (V/V) methanol buffer modifier and 20 kV. Un-der this condition, the 17 purine derivatives were baseline separated and the linear correlation coefficient for adenine,uric acid and 2-thioxanthine was 0. 99 over two orders of magnitude. The variation of peak areas was less than 4.6 %(n=5) and that of migration times was in the range of 0%-3%, while the samples were injected hydrodynamically at a height of 15 cm and an injection time of 8-10 s. In addition,alcohol, 1-propanol, 1-butanol and acetonitrile were also ef-fective additives in the separation. However, SDS and various β-cyclodextrin (β-CDs) were found to do no good to their se-paration.
Zeng Bai-zhao, Zhao Fa-qiongCollege of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, Hubei, China
