Briefly describe the precautions that should be taken during the experimental procedure for determining active silicon in water using the silicomolybdenum blue photometric method

Similarly, at the request of clients, we have also started analyzing the silicon content in circulating water recently. I learned from the national standards that it’s not very difficult. The most difficult one is probably the standard solution for silica; it cannot be prepared at home and must be purchased from outside. There is concern that the product purchased may not be accurate, which could lead to inaccurate test results later on.

The silicomolybdenum blue method for determining silicon content has quite high requirements regarding experimental conditions. Firstly, standard solutions should preferably be those that are approved for use in metrological purposes, or purchased from the instrument manufacturer; it is not recommended that users prepare them on their own. The reagents used for color development can be prepared according to standard methods, but due to the limitations of laboratory conditions in most users’ facilities, the shelf life of these reagents is relatively short. This is because the reducing agents used in the formation of molybdenum blue are unstable, and dissolved oxygen in air and water has an impact on them. For sample handling, since the purpose is to determine silicon content, glass and quartz products cannot be used for any sample processing; instead, polyfluoro or other engineering plastics that can withstand certain temperatures must be employed. For the preparation of the standard curve, try to control the ambient temperature as much as possible to keep its fluctuations as small as feasible. The color development time of the sample should be as consistent as possible with that of the standard sample. Strictly control the reagent blank; especially when detecting trace silicon levels, the reagent blank has a significant impact on the accuracy and reliability of the measurements

According to the measurement standards for all-silicon components, pipettes made of plexiglass are required, but I have asked many suppliers of accessories, and none of them have such pipettes. May I use a pipette with glass? Can glass volumetric flasks be used when calibrating the curve? Additionally, the cuvettes used in spectrophotometers can be made of glass or quartz; however, quartz cuvettes are very expensive, costing around 50 to 60 per unit, while glass cuvettes cost less than 10 yuan. The owner said that glass cuvettes are sufficient for normal use, and quartz cuvettes should only be used when measuring strong acids or substances containing fluorides. May I ask if glass can be used when measuring total phosphorus, total iron, and silicon?

This post was last edited by sunshineda_VGMP on 2018-3-21 09:45. To determine silicon, the pH must first be adjusted, and then measurement is carried out according to standards. Standard solutions of silica can be purchased on standard material websites, so there is no need to prepare them manually; however, this approach is cumbersome and may not yield accurate results. Active silicon can also be measured using a silica meter. When measuring silicon, it is necessary to avoid using glassware, as it may cause positive interference in the measurement.