Capillary electrophoresis of cytokinins and cytokinin ribosides

et al. 2006

Analyses of cytokinins are very important in both plant physiological and biomedical research as they are implicated in many biological processes. Reliable, sensitive, selective and inexpensive methods that are flexible and designed for automation are required for these analyses. This review addresses the advances made in the separation and determination of cytokinins by CE as well as the other applications of CE (i.e., determination of dissociation constants and complexation constants of cytokinins). The various CE modes used to separate the compounds and the quantification strategies are examined. Special attention is also focused on those aspects that improve on the sensitivity and/or selectivity, such as sample extraction and preconcentration, on-line preconcentration techniques (stacking), and/or specific detectors (e.g., MS). With the coupling to the preconcentration techniques and certain detection systems, numerous CE methods can potentially be adapted for the analysis of cytokinins in complex biological samples. Therefore, we would anticipate wider applications of CE methods in the near future for cytokinin analyses, which should facilitate a decrease in analysis cost and should help to improve analysis efficiency.

Section: Modes Of Operationmentioning

confidence: 99%

Section: Czementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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CE for cytokinin analyses: A review

et al. 2006

Analysis of positional isomers of hydroxylated aromatic cytokinins by micellar electrokinetic chromatography

et al. 2005

A micellar electrokinetic chromatography (MEKC) method was developed for the separation of six positional isomers of hydroxylated aromatic cytokinins (topolin and topolin riboside), including ortho-topolin, meta-topolin, para-topolin, ortho-topolin riboside, meta-topolin riboside, and para-topolin riboside. Optimum resolution and analysis time (ca. 20 min) for the six aromatic cytokinin standards were achieved with a running buffer at pH 8.0 consisting of 20 mM boric acid, 50 mM sodium dodecyl sulfate (SDS), and 20% v/v methanol. The method has good reproducibility and has been successfully applied to detect the presence of a putative ortho-topolin in coconut water extract sample purified using C(18) and mixed-mode solid-phase extraction (SPE) columns. Other advantages of this MEKC method are short analysis time, low solvent consumption, and separation of positional isomers which could be achieved by a simple aqueous buffer system without the use of expensive chromatographic columns. In addition, a high-performance liquid chromatography (HPLC) method with baseline separation of the six topolin and topolin riboside standards was developed for the confirmation of the endogenous ortho-topolin in coconut water sample. Finally, the presence of ortho-topolin was further confirmed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) based on its characteristic fragmentation pattern.

Determination of cytokinins in coconut (Cocos nucifera L.) water using capillary zone electrophoresis‐tandem mass spectrometry

et al. 2006

Determination of cytokinins in coconut (Cocos nucifera L.) water using capillary zone electrophoresis-tandem mass spectrometryThe applicability of CZE in combination with MS and MS/MS methods for the simultaneous separation and determination of 12 cytokinins was investigated for the first time. Cytokinins were first completely separated by CZE within less than 20 min using a volatile buffer and then detected directly by MS or MS/MS. Satisfactory separation of the 12 cytokinin standards was achieved using a 25 mM ammonium formate/formic acid buffer (pH 3.4) and 3% ACN v/v with a separation voltage of 25 kV. On the basis of the resolution of the neighboring peaks, the various parameters for CZE-MS optimization, such as buffer pH value, concentration of buffer and organic modifier, applied voltage and sheath liquid, were evaluated systematically. MS/MS with multiple reaction monitoring detection was carried out to obtain sufficient selectivity and sensitivity. The combination of on-line sample stacking and CZE-MS/MS achieved a detection limit in the range of 0.05-0.18 mM for the 12 cytokinins at an S/N of 3. The optimized CZE-MS/MS method was simple, rapid, low cost, robust and highly selective. Furthermore, the developed method was successfully applied to screen for endogenous cytokinins in purified coconut water extract sample. Nine cytokinins were detected and quantified in coconut water after SPE.