ã€Fundamental】 The base contained in the nucleic acid molecule allows the nucleic acid to have maximum absorption at 260 nm. Ultraviolet absorption is a property of the conjugated double bond system of the anthracene ring and the pyrimidine ring. The substance containing purine and pyrimidine has the property of absorbing ultraviolet light whether it is a nucleoside, a nucleotide or a nucleic acid. Because proteins contain aromatic amino acids, they also absorb ultraviolet light. Usually, proteins have specific absorption at 280 nm. Therefore, the ratio of nucleic acid in A260 and A260, A280 (A260/A280) can reflect the content and purity of nucleic acid in the sample. The ratio of RNA to A260/A280 is above 2.0; the ratio of DNA to A260/A280 is about 1.8. The ratio decreases as the protein content of the sample is higher. ã€equipment】 Ultraviolet spectrophotometer 2. UV lamp or gel imager ã€Reagents】 Double steamed water 2. DNA sample or RNA sample ã€Steps】 1. Dilute the sample with an appropriate amount of water or TE. 2. Use 1 ml of water (or TE) to make a blank zero. 3. Place the sample cup in the spectrophotometer colorimetric cell. 4. Measure the absorbance of A260 and calculate the DNA or RNA content of the sample. 5. If the sample purity is detected, the A280 value should be measured again, and the ratio of the two should be calculated. If the ratio is about 1.6, it means that there are proteins or other impurities that absorb this wavelength. It is recommended to use phenol/chloroform extraction, followed by extraction. Ethanol precipitation to remove impurities. Shanghai Chuangsai Technology has excellent performance, interleukin cytokines, fetal bovine serum, electrophoresis equipment scientific instruments, raw material drug standards, chemical reagents, cell culture consumables, Shanghai Chuangsai, mass products special promotions, welcome to inquire! Pet Electronics Toys,Cat Electronics Toys,Electronics Toys Ningbo XISXI E-commerce Co., Ltd , https://www.petspetstoys.com