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FAQ

What is the principle of micro-spectrophotometry? What are the common uses?

Spectrophotometer is a kind of instrument for quantitative and qualitative analysis of substances by spectrophotometry. Spectrophotometry is the qualitative and quantitative analysis of the substance by measuring the absorbance of the measured substance at a specific wavelength or within a certain wavelength range.

When monochromatic light radiation passes through the measured substance solution, the amount absorbed by the substance is directly proportional to the concentration of the substance and the thickness (optical path length) of the liquid layer. And the relationship is as follows:
A=-lg(I/I.)=-lgT=kLc
Where: A is the absorbance;
I. is the intensity of incident monochromatic light;
I is the intensity of transmitted monochromatic light;
T is the transmissivity of the substance;
K is the molar absorption coefficient;
L is the light path of the substance being analyzed, i.e. the side length of the cuvette.
C is the concentration of substance;

The selective absorption wavelength of light of the substance and the corresponding absorption coefficient of the substance are the physical constants of the substance. When the absorption coefficient of a pure substance under certain conditions is known, the sample for test can be prepared into a solution under the same conditions, and its absorption degree can be determined, then the content of the substance in the sample for test can be calculated from the above formula. In the visible light region, except some substances have absorption of light, many substances do not absorbance, but they can be determined by adding color reagent or after treatment under certain conditions, so it is also called colorimetric analysis. Because there are many factors that affect the shade of color, and the instrument with poor purity of monochromatic light is often used, the standard or reference substance should be used at the same time.

Application fields:
Ultramicro spectrophotometer has become a conventional instrument in modern molecular biology laboratory. It is often used to quantify nucleic acid, protein and bacterial growth concentration.

Temperature calibration of dry bath incubator

Dry bath incubator is a constant temperature dry bath device controlled by microcomputer instead of traditional water bath device. It can be widely used in sample preservation and reaction, DNA amplification and pre denaturation of electrophoresis, serum coagulation and other fields.

In the actual use of the dry thermostat, customers often worry about the accuracy of the temperature, especially for the customers who have been using the dry thermostat for many years.

Usually, customers do not have complete testing instruments and perfect testing methods to evaluate the temperature accuracy of the instrument. Therefore, we generally recommend that the customer send the dry thermostat back to the manufacturer for re testing, and the manufacturer will evaluate the accuracy of the instrument temperature.

The necessary conditions for temperature calibration of dry bath incubator are as follows:
1. Environmental requirements: We require temperature calibration at ambient temperature of 15 ℃ ~ 25 ℃.
2. Humidity requirements: The humidity should be lower than 85 %.
3. One of the most important instruments for temperature calibration: the national second-class standard thermometer (0.1 ℃ scale), and it must be verified by the authoritative department. (For modules with large module holes) Ordinary thermometers or high-precision thermometers that have not been calibrated are not allowed.
4. The second most important instrument for temperature calibration: high precision thermistor and other sensors, and they must be verified by the authoritative department. (For modules with smaller module holes)
5. Test requirements: when the national second-class standard thermometer and high precision sensor are put into the module hole, they must contact the module very accurately. Generally, heat conducting oil (high temperature resistant oil, usually the ignition point must be higher than 200 ℃) and silicone grease are added into the hole.
6. Testing method: complete temperature calibration methods and instructions provided by the manufacturer

If users have the above prerequisites, they can calibrate the temperature by themselves.

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