Spectroscopic Optical Multi Meteradmin
Spectroscopic optical multi meter how to absorb the luminosity of stray light correction?
First, spectrophotometer to stray light correction?
1.Spectroscopic optical multi meter correction methods: correction absorbance commonly used a very pure substance a certain concentration of solution as the standard, and the solution’s absorbance coefficient by different laboratory to check, in order to make the standard liquid absorbance is not affected by measuring wavelength of micromotion and have change, often choose the material with a smooth absorption peak, solution stability is also required.
2. The correction method of stray light: small amount of stray light often can cause larger error of measurement, calibration of it available a fully absorb some wavelengths of light, and in other wavelength absorption solution is very weak. From the solution of pervious to light situation can be speculated that stray light of approximation. Pseudo absorption band caused by the stray light, also can use Beer – Lambert’s law to check, but with the law of error check false absorption band.
Second, absorb spectrophotometer luminosity.
In quite a wavelength range of absorbance change in line with the Beer – Lambert’s law, copper sulfate, sulfuric acid is commonly used in drilling and sodium nitrate or potassium solution. Potassium chromate solution is the most commonly used standard solution, the solution in the ultraviolet and visible region are applicable.
By cutting off outside performance of transmission ratio can be obtained by the approximate percentage of stray light. If stray light is more than 0.1% contained, should try to reduce, or to absorb the photometric calibration. Error caused by stray light is proportional to the stray radiation, so correction easily from the compound of close to the right curve calculation. In addition, an appropriate filter are available, and the filter in barium J wavelength range completely pervious to light, but to absorb the light outside this range, thus to tip in addition to stray light.
Third, the use of the spectrophotometer
1. If a substantial change test wavelength, need to wait a moment, such as lamp after thermal equilibrium, recalibration “0” and “100%” point. Then measured.
2. The pointer instrument when not connected to the power meter pointer must be in a zero on the scale. If it is not this kind of situation, need to mechanical zero.
3. Color plate after using, please immediately use distilled water is rinsed clean, will water wipe with clean soft cloth, in order to prevent the surface finish was damaged, affect the color light transmittance of dish.
4. The operator should not be easily move the light bulb and the reflector lamp, so as not to affect the light efficiency.
Fourth, the spectrophotometer itself advantages
Spectrophotometer, due to its photoelectric receivers for photomultiplier tubes, itself is characterized by large magnification, thus it can be used to detect weak photoelectric signal, and cannot be used to detect light. Otherwise easy to generate signal drift, reduced sensitivity.
2. After amplifier sensitivity shift, must be zero.
3. The colorimetric cup. Outstanding problems. Colorimetric cup must be used, otherwise will lose test results, and before each test shall be compared.