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OD260 / 280 ratio is too high? The final step to see what you dissolve, if it is kit of elution, the ratio will be high point, if dissolved in distilled water may be a little better, but look at your ratio, you should have little effect behind the experiment. OD260 / 230 appear negative, you look at which value is negative. If it is 260 value is negative, it may be your little amount of DNA in the vicinity sequence of the baseline, this time measurements are often inaccurate, baseline itself sequence is not a very flat, straight, sequence your 260 value may be negative. sequence Not mean no DNA, but less pure DNA: OD260 / OD280 1.8 (> 1.9, indicates a RNA contamination; <1.6, indicating a protein, phenol and other pollution)
OD is the optical density (optical density) sequence of the abbreviation, OD = 1og (1 / trans), in which the transmittance value detection trans thereof. Absorbance of the absorbance, absorbance, refers to a solution or the number of light through the material prior to the incident sequence light intensity with the light through the material after the solution or transmitted light intensity ratio, the factors which influence the solvent, concentration, temperature, etc. absorptivity sequence and the material sequence is light and the wavelength of the incident light through. As long as the wavelength of light is fixed, the same substance, the absorption coefficient is constant. When a beam of light through a light-absorbing substance (usually a solution), the solute sequence absorbed light, the intensity of light is weakened. Is used to measure the absorbance of light is absorbed by a physical extent. The absorbance is represented by A, A = abc, where a is the extinction coefficient, the unit L / (g cm), b for the liquid layer (usually the thickness of the cuvette), the unit cm, c is the solution concentration in g / L is the influence of the absorbance factor sequence b, and c. A is a constant associated with the solute temperature by influencing c, while the impact of A. Generally speaking on behalf of nucleic acid absorbance OD260, sequence OD280 representative protein absorbance, OD230 on behalf of other impurities (polysaccharides) absorbance. A260 / A280 with OD260 / OD280 meaning is the same. A represents an absorbance, and OD is the optical density value, a meaning. A260 / 280 ratio to determine nucleic acid purity became the sole universal standard, sequence pure DNA is generally between 1.8-2.0; later found that many of the reagents used in the extraction process affect A260 and A280 readings; sequence Meanwhile, on the same sample 10 multiple orders sequence of magnitude absorbance measured after diluting found spectrophotometer absorbance values only in a certain area is linear. Conclusion: When the reading is between 0.1-0.5 A260, A200 to A320 between numerical form a smooth curve, 4 equipment limitations: When measuring OD260 and OD280 values between 0.1-0.5 make OD260 readings . This range of linear best. Diluted sample: OD values measured in control and sample dilution use 10mM Tris, pH7.5. Water as the diluent will result in a low ratio. sequence The ratio of low protein contamination may have high DNA contamination sequence that may have suggested that you extracted RNA sub-three, two saved, another sequence pipe glue and determination to run OD, ran glue is the most intuitive, 1% of the glue on Yes, immediately after extraction run, generally will not degrade a lot, so no need to go to the enzyme treatment equipment and materials will not be influential. Your od may be lower than when using acidic PH value of water is dissolved. You can try to retest transferred about 8.0, so it will come up.
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