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Spectrophotometer
Shimadzu AA-7000 Atomic Absorption Spectrophotometer
The spectrophotometer, at its essence, measures light intensity. By comparing the intensity of light before and after it passes through a sample, this instrument provides invaluable data on a sample’s properties, especially in medical diagnostics.
The spectrophotometer, while perhaps not the most renowned, is undoubtedly one of the most impactful instruments in medical diagnostics. Its blend of precision, versatility, and speed positions it as an indispensable ally in modern medicine. As technology marches forward, its luminescence in healthcare will only shine brighter.
A spectrophotometer is a scientific instrument used to measure the intensity of light at different wavelengths. It is an essential tool in many scientific fields, including chemistry, biochemistry, and molecular biology, for analyzing the concentration and properties of substances in samples.
Hong Kong Dazheng Group Limited offers a range of top-quality spectrophotometers, from basic models to advanced systems with multiple detection modes and software capabilities. Trust in the precision and accuracy of our spectrophotometers to advance your research or clinical practice. Browse our selection today and take the next step in enhancing your scientific capabilities.
Instrument features
Unique dual-optical path, dual-beam optical system, the instrument has higher resolution, lower stray light, stronger stability and reliability, and more accurate analysis;
Adopting 320*240 bit dot-matrix high brightness 6” LCD display, clear display and complete information;
Unique long optical range optical path design, so that the instrument resolution is higher, especially suitable for micro-volume testing Powerful data processing functions, so that the test results can be fully applied, user editing more simple and fast;
Adoption of suspension optical system design, the overall optical path is independently fixed on the 16mm thick aluminum non-deformation base, the deformation of the base plate and external vibration does not have any effect on the optical system, thus greatly improving the stability and reliability of the instrument;
Adopting synchronized sinusoidal mechanism with high wavelength accuracy and good repeatability;
Adopting ARM system;
0.1/0.2/0.5/1.0/2.0/4.0 six grades of spectral bandwidth automatically selectable to meet the measurement needs of different users;
24-bit high-speed, high-precision A/D conversion, the instrument is more accurate and faster response speed;
The main components are imported configuration, so that the instrument stray light is lower, stability and reliability;
More powerful functions, the host can independently complete the photometric measurement, quantitative measurement, spectral scanning, kinetics, DNA/protein testing, multi-wavelength testing and data printing and other functions;
Fully consider the use of different user habits, this series of instruments are standard with the company's spectral scanning software, on-line operation, in addition to realize all the test functions of the host, but also to achieve a more powerful data processing functions, and make the data storage to reach unlimited.
Common Uses
Quantification of Nucleic Acids
Quantification of nucleic acids is the most frequently used function of a spectrophotometer. It is possible to quantify buffer-soluble oligonucleotides, single-stranded and double-stranded DNA, and RNA, the highest absorption peak of which is at a wavelength of 260 nm. Each type of nucleic acid has a different molecular composition, and therefore has a different conversion factor. To quantify different types of nucleic acids, the corresponding coefficients should be selected beforehand. For example, the absorbance value of 1OD is equivalent to 50 μg/ml of dsDNA, 37 μg/ml of ssDNA, 40 μg/ml of RNA, and 30 μg/ml of Olig. The absorbance values after the test are converted by the above coefficients to obtain the corresponding sample concentration. Prior to testing, the correct program was selected, the volumes of stock and diluted solutions were entered, and the blanks and samples were then tested. However, the experiment was not always smooth. Erratic readings can be a major headache for the experimenter. The higher the sensitivity of the instrument, the greater the drift in absorbance values.
Direct quantification of proteins (UV method)
This method is at 280 nm and tests proteins directly. By selecting the Warburg formula, the photometer shows the concentration of the sample directly, or by selecting the appropriate conversion method, the absorbance value is converted to the sample concentration. The protein determination process is very simple, first test the blank solution, and then test the protein directly. Due to the presence of some impurities in the buffer, it is usually necessary to eliminate the “background” information at 320nm, and this function is set to “on”. Similar to the testing of nucleic acids, the absorbance value of A280 is required to be at least greater than 0.1A, and the optimal linear range is between 1.0 and 1.5. When the Warburg formula was selected to display the sample concentration, the reading “drifted”. This is a normal phenomenon. In fact, as long as the absorbance value of A280 is not observed to vary by more than 1%, the results are very stable. The reason for the drift is that the Warburg formula converts the absorbance value to concentration, multiplied by a certain factor, and as long as there is a small change in the absorbance value, the concentration will be amplified, thus making the results appear very unstable. The direct protein quantification method is suitable for testing pure proteins with relatively single components. The UV direct quantification method is fast and easy to operate compared to the colorimetric method; however, it is susceptible to the interference of parallel substances, such as DNA; in addition, the sensitivity is low and requires a high concentration of protein.
Colorimetric protein quantification
Proteins are usually mixtures of multiple proteins, and colorimetric determination is based on the reaction of protein constituents: amino acids (e.g., tyrosine, serine) with an additional chromophore group or dye to produce a colored substance. The concentration of the colored substance is directly related to the number of amino acids with which the protein reacts, and thus to the protein concentration.
Colorimetric methods
Maintenance
Spectrophotometer as a precision instrument, in the operation of the work process due to the working environment, operating methods and other reasons, its technical status will inevitably occur certain changes that may affect the performance of the equipment, and even induce equipment failure and accidents. Therefore, analysts must understand the basic principles of spectrophotometer and the use of instructions, and can be found in a timely manner and exclude these hidden dangers, has produced timely maintenance of faults in order to ensure the normal operation of the instrument.
