Capillary electrophoretic determination of silicon in plants

• Silicon has been determined by capillary electrophoresis (CE).
• Method of plant materials preparation for Si determination is developed.
• Method is suitable for the determination of traces of Si in plant materials.
• Determination of total silicon in different plant samples was carried out.

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 determination of silicon in plants, which to the best of our knowledge has not been done before. The dynamic concentration range of determination is 0.05–2 mg/l, detection limit — 0.02 mg/l. Analysis of different plant samples showed that the method is suitable for determination of silicon in plant materials down to trace amounts (0.1 mg/g) with satisfactory validity. Overall analysis time is 50–52 min.