Calculate concentration from absorbance and molar extinction coefficient?
I have a protein of unknown concentration. When measuring its absorbance using 1cm cuvette, I have to dilute the sample 2000 fold in order to obtain an absorbance reading within the linear range. The absorbance of the diluted sample is 0.4875. The molar extinction coefficient is of the protein is 1.55. What is the concentration?
How to calculate concentration given absorbance?
I'll give you a road map to solve the problem: 1. Using Beer's Law (A = ebc, where A = absorbance, e=molar absorption coefficient, b is path length, and c is concentration); rearrange to solve for c: c = A/(eb) Since we're given its absorbance, the path length, and molar absorption coefficient in the problem, we can calculate concentration (in units of mol/L). 2. Using the answer to step 1 and the molecular mass of cytochrome given in the problem, we can calculate the concentration of the diluted cytochrome sample in units of g/L. 58kDa = 58,000 Da = 58,000 g/mol. 3. Using the answer to step 2, convert the concentration from g/L to mg/mL. 4. Using the answer to step 3 (the diluted concentration of cytochrome) and the sample preparation information (dilution step) given in the problem, calculate the original concentration of cytochrome. hope that help
Calculating concentration using absorbance and percent transmittance?
I'm a bit confused on how I would go about finding concentration given those two. I am assuming Beer's Law is involved? Could someone please explain the process? :D Also I have one of the calculations as absorbance = .21 and the %T =61 Thanks to anyone that helps. Sorry about my English it's not my native language (:
How do you calculate path length, if only given absorbance, concentration, and %transmittance at 530 nm?
Three ways to answer this. 1.) Obidience and compliance- MIlgrams famous study was provoked by the holocaust. He found, of normal everyday Americans off the street, 60% would continue electricuting some until they died (they believed) if instructed to. The idea is you hand over responsibility to someone of higher rank (a similar thing was applied to the American soilders bombing a villiage of women and children in Vietnam) 2.) Depersonalisation: In any case of genocide, there are a few universal conditions: an us - them attitude towards the percieved underclass, depersonalistion of the perceived underclass (Jews, dark skinned races, homosexuals were considered lesser than the perfect race), blaming them for all the problems, believing that the country is in a state of crisis - an extreme solution is needed, and a strong leader 3.) More recently, psychologists have dismissed Milgram's view at least as it applies to the higher level of the chain of command (it might still apply to you bulldozer driver). Several of the camp guards actively and imagineitively interpreted orders that did not actuall call for the holocaust, orders being very vague. There was an air of competetion for Hitler's favour. The guards were committed to what they were doing, knew what they were doing, and they thought it was the right thing to do. They thought they were killing an enamy, they take on the ideology of the group that condones this behavoir Most of the people that were "responsible" were sentenced at the nuremberg trial. Others lower down were more likely to be (or at least feel) they were just following orders, thus avoiding guilt that would lead them to suicide. Those that took on the ideology would not feel guilt
How to find concentration with given absorption and wavelength?
What you need to understand is the Lambert-Beer law which can be expressed by the following relation : A = e c l, where A is the Absorbance of the solution, c is the concentration of the solution expressed in mol/dm3, l is the path length in cm (in your case if you have used a spectrophotometer, then u must have used a quartz cuvette for holding the sample, which typically has a path length of 1 cm ) and e is the Molar Absorption co-efficient. So if you know the value of Molar Absorption co-efficient of your sample ( you can check on the internet if you don;t know the value), then use the above relationship to get the concentration of your sample. Hope I helped...:)
How to calculate the percentage transmittance given the absorbance and a formula.?
RE: How to calculate the percentage transmittance given the absorbance and a formula.? Given the absorbance = .081 How do we calculate the percent transmittance given the formula: A=-log(%T/100) P.S. I really don't remember how logs work so please help me somebody :( Thanks.
Chemistry questions about how to calculate Absorbance?
For the best answers, search on this site https://shorturl.im/MtJzl a) 0.33 @ 260nm; 0.14 @ 340nm b) 0.75 @ 260nm; 0.044 @ 340nm The absorbance at a given wavelength is directly proportional to both the concentration of the absorbing solute and the path length of the cuvette. The proportionality constant is the molar extinction coefficient at that wavelength. This is given by Beer's Law. For each of the above, I found the product of the molar extinction coefficient, the concentration, and the path length. In part b, the total absorbance was the sum of the absorbances of the constituent absorbing solutes. All answers were expressed to 2 significant figures. I hope this helps!
The absorbance vs wavelength graph is insufficient for a quantitative analysis.It does show that the compound of interest absorbs in the UV region, which suggests that a spectrometric analysis can be developed.You would tend to pick a wavelength where your compound of interest absorbs strongly (making the assay more sensitive) and where slight errors in setting the wavelength would not have a big effect (so 205 and 243 nm would be good; 220 nm would not).You would then make several standard solutions of your compound of interest that would be expected to cover the absorbance range of roughly 0.05 to 1.00 (because spectrophotometers are most accurate in this range), and plot their concentration vs absorbance. Typically this graph will be a nearly straight line (see Beers’ Law), and it is your “calibration curve”.They you measure the absorbance of an unknown and compare it to the calibration curve. You can read the concentration directly off the calibration curve, and you’ve got your analysis.Then there are the finer points of analytical chemistry: is your unknown always expected to be pure? or are there impurities present? If impure, do the impurities absorb at the wavelength used in your analysis? Not good! There’s more, but I’m not an analytical chemist.
A simple example would be this value defines a material’s “color”.The wavelength of light ( well really all electromagnetic radiation even that which our eyes can’t see ) absorbed by an object, or rather what it does not absorb, defines a substance’s “color”.How much of light of any particular wavelength (or color) an object absorbs is what a graph of wavelength vs absorption is a chart of.The light it does not absorb is either reflected in the case of an “opaque” object, or transmitted through the object and this can be measured.
How do u calculate concentration in Beer lambert law?
If you make a graph of absorbance versus concentration, if the absorbing species obey's Beers lambert's Law..then you will get a straight line. You can then have software of various types ( even excel ) can give the equation representing that straight line in the form y = mx + b if you plot the concentration on the Y axis and absorbance on the x axis .then the above equation would be Y ( concentration in whatever units the graph was derived from ) = slope x ( absorbance value ) + intercept. So if the predictive equation were y = 0.93 X + 0.1 for a Beer's Law line plotting absorbance vs concentration i mg/mLand the absorbance value of your unknown sample were 0.5 then the concentration would be 0.93 ( .5 ) + 0.1 = 0.565 mg/mL Alternatively plot the straight line ..determine the absorbance of your sample ..then draw a perpendicular from the straight line to the concentration based on the absorbance value for your sample