|
|||||
|
|
Microwave Digestion for Colorimetric Determination of Total Si in Plant and Mineral Samples |
|
| Authors: | Liu Saihua Xie Yunhe Xionghui Ji Huang Juan E A Bocharnikova |
| Institution: | 1. Institute of Agro-Environment and Ecology, Hunan Academy of Agricultural Science (HAAS), Changsha, China;2. Key Laboratory of Agro-Environment in Midstream of Yangtze Plain, Ministry of Agriculture, Changsha, China;3. Department of Physico-Chemistry of Soil, Institute of Physical-Chemical and Biological Problems in Soil Science RAS, Pushchino, Russia |
| Abstract: | A new method for determining the soluble silicon (Si) concentrations in nonliquid plant and mineral samples was developed using sodium hydroxide (NaOH)–hydrogen peroxide (H2O2) matrix for microwave digestion (MWD-Na) followed by colorimetric Si testing. MWD-Na was compared with autoclave-induced digestion and alkali fusion. The data have shown no significant difference between these three methods. HNO3–H2O2 or HNO3?–H2O2?–HF microwave technique results in Si loss. The reduction of the total Si can be realized via low solubility of Si in the acid solutions or silicon tetrafluoride formation. The Mullen and Riley method for colorimetric testing of Si in a solution that uses ascorbic acid to reduce the silicomolybdate complex formed under acid conditions to an intensely blue complex was modified using iron sulfate. The combination of MWD-Na and modified colorimetric blue method provides cheap and valid data on determining the total Si in both plant and mineral samples. |
| Keywords: | Alkali fusion autoclave digestion microwave digestion plant sample digestion silicon |