Petri Dish Matching use of cuvette
The cuvette must be used together, otherwise the test results will be meaningless. A comparison should be made before each test.
The specific methods are as follows; inject the same solution into the two cups to be tested, place the instrument at a certain wavelength, a quartz cuvette; 220nm, 700nm filled with distilled water, glass cuvette: 700nm filled with distilled water, put a certain The transmittance value of one cell is adjusted to 100%, and the transmittance values of other cells are measured, and the difference between the displayed value and the light transmission direction is recorded. The impact on the test results should be considered.
The following problems should be brought to the attention of instrument operators:
1) The correct positioning of the cuvette holder and cuvette in use. Some users do not pay enough attention to this problem, and accidental errors due to improper operation seriously affect the analysis results. First, make sure that the cuvette is not tilted. A slight tilt will make the reference sample and the sample to be tested inconsistent in the length of the absorption light path, and may also prevent all incident light from passing through the sample cell, resulting in a test ratio accuracy that does not meet the requirements. Secondly, it should be ensured that the cuvette holder is pushed and pulled into place during each test. If it is not in place, it will affect the repeatability or accuracy of the test value. Finally, the cleanliness of the cuvette should also be guaranteed to extend its service life.
2) The use of desiccant. The failure of the desiccant will cause a) the digital display is unstable, unable to adjust the "0" point or "100%" point (the circuit or the photocell is damp). b) The mirror is moldy or contaminated, affecting light efficiency and increasing stray light. In view of the above reasons, the spectrophotometer should be placed away from places with high humidity, such as pools, and the desiccant should be replaced or baked regularly.
3) The working environment of the instrument. Avoid direct sunlight, avoid strong electric fields, avoid sharing electricity with larger power electrical equipment, and avoid corrosive gases.