Do you know the common uses of spectrometers?

Direct quantification of protein (UV method)

This method directly tests protein at a wavelength of 280nm. Select the Warburg formula, and the photometer can directly display the sample concentration, or select the corresponding conversion method to convert the absorbance value into the sample concentration. The protein determination process is very simple. First test the blank solution, and then directly test the protein. Because there are some impurities in the buffer, it is generally necessary to eliminate the "background" information of 320nm and set this function to "on". Similar to the test of nucleic acid, the absorbance value of A280 is required to be at least greater than 0.1A, and the best linear range is between 1.0-1.5. When the Warburg formula is selected to display the sample concentration in the experiment, the reading is found to "drift". This is a normal phenomenon. In fact, as long as the variation range of the absorbance value of A280 does not exceed 1%, it shows that the result is very stable. The reason for the drift is that the absorbance value of the Warburg formula is converted into concentration and multiplied by a certain coefficient. As long as the absorbance value changes slightly, the concentration will be amplified, making the result appear very unstable. The direct protein quantification method is suitable for testing relatively pure proteins with relatively simple components. Compared with the colorimetric method, the UV direct quantitative method is fast and simple to operate; however, it is easily interfered by parallel substances, such as DNA; in addition, it has low sensitivity and requires a higher protein concentration.