© 2016 Elsevier B.V.. A very limited number of methods for the determination of silicon are used. The classic analytical methods (gravimetric, photometric) and modern methods ICP-MS and ICP-AES are applied for the determination of silicon in plants, whereas the latter has an advantage because the sample preparation is not necessary. However, the reliability of the results obtained by ICP-AES is disputable. Conventional methods of sample preparation for silicon determination are time-consuming and difficult to perform; therefore, there is a critical need for development of more effective sample preparation procedures. Herein, we report the improved method of sample preparation for determining of silicon in plant materials. The method includes dry ashing, followed by oxidative degradation in HClO4 and dissolution of formed silica in a mixture solution of potassium hydroxide and NaEDTA. Proposed method of sample preparation is more reliable and rapid (40 min). We employ the capillary electrophoresis (CE) for det