Standard Curves
Standard curves are critical for many analytical research procedures.
Read about standard curves here:
1. http://www.graphpad.com/curvefit/introduction5b.htm
2. http://en.wikipedia.org/wiki/Standard_curve
3. http://a32.lehman.cuny.edu/molbio_course/std.htm
In 250-350 proofed, succinct words, describe a practical research application for a standard curve. Explain the value of the curve and how can it assist the scientist.
posted by Frank LaBanca, EdD @ 8:26 AM
11 comments
11 Comments:
A standard curve is a graphing function or method for plotting assay data of known solution concentrations to determine the unknown concentrations of similar solutions. It is extremely valuable in the study of proteins and DNA. The assay may be measured in numerous ways including absorbance, optical density, luminescence, fluorescence, and radioactivity. A practical application of the standard curve is in the determining of concentrations of dye in fruit juices. This application is important in the field of nutrition and in exposing certain companies who claim to have all natural ingredients. Also, knowing the that a certain juice used artificial dye could prevent reactions for those children who may have allergies to specific ingredients in a particular dye. This process would be carried out as a colorimetric standard curve. Using known concentrations, a researcher could verify the concentration of artificial dyes in juice brands which may have falsified their own concentrations for the purpose of selling their product. A spectrophotometer would be used to determine the amount of light passing through each juice sample. This absorption would be the dependent variable and be the value of the y-axis. The dye concentration would be the independent variable and be the value of the x-axis. This experiment could test one specific type of juice, for example by testing different brands of apple juice. This would determine which brand incorporates the least dye in their recipe. Another experiment would be to compare different types of juices, for example testing the same brand of apple, grape and cranberry juice. This would reveal the practices of one particular brand and/or company. This could be extended into testing these three juices for all or many different brands, and then again proceed to compare the companies dye concentration levels.
A standard curve is a tool that is used to plot assay data that determines the concentration of a substance. By the way, an assay is a procedure where a property of a system or object is measured.
A standard curve is a way of graphing data resulting from an analysis of a concentration of a substance. Most commonly, a spectrophotometer is used for this purpose. The absorbence of a certain frequency of light is measured in a set amount of a known concentration of the substance in question, and the spectrophotometer zeroed at this concentration, and the unknown concentration of the substance is measured. On the graph, the concentration is plotted on the x axis, and the assay meaurement is plotted on the y axis, and a line is drawn to follow this curve. This is the standard curve. It can be used for many different purposes, and does not have to be measured by a spectrophotometer. It can be used with radioactivity, or any other indicator of the amount of a substance. A useful application for it is to analyze commercial products when the amount of an ingredient contained within them is in question, and there is no easier way to find out the concentration. A practical application for this would be, for example, determining the concentration of some hydrocarbon in a sample of water that is suspected to be polluted. A standard curve would first be made with the data resulting from a spectrophotometric analysis of a sample of water with a known concentration of the hydrocarbon in it, and then a standard curve would be made from an analysis of a sample of the water in question. These together could be used to mathematically calculate the concentration of the hydrocarbon in the unknown sample of water.
A practical research application for a standard curve is to determine the concentration of a know substance in multiple unknown samples. To do this scientist first needs to make the curve, which can be based on sundry of properties: density, optical density, electrical conductivity, radioactivity, florescence, luminescence … etc. The user of the curve needs to make two or more known concentrations of the substance and measure the most suitable quantitative trait for the curve. These concentrations are graphed on the X-axis while the corresponding assay measurement is graphed on the y-axis. The curve is then fit onto these points, usually using a graphing program. The curves accuracy will depend on the amount of points on it, so if the researcher used more knows to plot his curve it will be more accurate. Once the curve has been created it can be used to measure the concentration in the unknowns. The researcher simply needs to measure the selected trait in the unknown and find the corresponding concentration from the x-axis. This makes it easy to find the concentration of many unknowns quickly because you simply need to measure one trait and find that measurements corresponding concentration. One example is a researcher using a standard curve to find the phytoplankton concentrations across the ocean surface to determine the condition of that area. The researcher would have many unknowns and he could quickly measure the concentration of his samples using a curve. A reasonable trait for the researcher to base his curve on would be optical density. The researcher would use a spectrophotometer to measure the optical density. The samples assay data would then be used on the curve to find its corresponding concentration.
A standard curve is used to determine the concentration of a substance that is unknown. To start the standard curve test known concentrations of similar solutions, one way to do this is using a spectrophotometer to measure absorption when compared with concentration. After you test your “knowns” and make a standerd curve you can test your unknowns and compare. When you place your “unknown” concentration in the spectrophotometer you are able to get this solutions absorption. By taking the absorption and comparing it to the graph previously made, you can determine the unkown concnetration of the solution. This is usually a colorometric process. This use of a standar curve could possible help in my project for testing whether a brook trout is native or non native or a cross breed of native and non native in a given watershed or river. This can help the field of environmental science because it can show the health of the fragile fish in a certain ecosystem. This experimentation method would be a good indicator that something is wrong with a certain ecosystem. Another application of the standar curve is testing the water quality that I will be working with when testing trout. I will be able to use assays for different common contaminats of water resevoirs. Such contaminants include PCBs and other heavy metals. Hopefully by having this information I can assess the differences between different areas of water and how their quality effects the native and non-native trout in that habitat.
A standard curve is a tool used in research the concentration of substances quantitatively. It is used to find the concentrations of unknown substances. This is done by comparing the assay data of the unknown substance concentrations to that of the known. It has been used particularly to find the concentrations of proteins and DNA. The standard curve has been used to find the protein concentrations in substances. A standard curve of known protein concentrations was made using bovine serum albumin. Then other unknown concentrations were compared with the standard curve. The primary things that are measured in an assay procedure are absorbance, optical density, luminescence, fluorescence and radioactivity thou other means can be used. The main means of finding a concentration is with light absorbance, which is measured by the spectrophotometer. The way this is done is by measuring the absorbance of a specific frequency of light by a known concentration of a substance. Then zeroing the machine to that absorbance and then measuring and comparing all subsequent unknown concentrations. The standard curve can be used to verify the concentration of substances in different consumer products. An example might be the amount of dye in fruit juices or the amount of a specific protein in meat products or the amount of a certain chemical in beauty products. Finding the concentration of a chemical in beauty products could be done by first make a standard curve of a known concentration of the chemical. Then adding a dye or some kind of reactant, to one of the beauty products, that will bond to the chemical changing its color. Then running it through the spectrophotometer and comparing it to the standard curve to find the concentration.
Standard curves are a basic method of calculating concentrations of unknown substances. First, multiple assays are performed using different known concentrations. Next, whatever is being calculated (density, luminescence, fluorescence, etc…) is found, it can be graphed and a best-fit line can be installed. It is on this line that once the unknown is tested, it can be located on the graph and the results can be found.
One practical use for a standard curve is testing for liver glycogen in fish in order to compare the water quality of two salt marshes. By plotting a standard curve of know concentrations of liver glycogen, the unknown percentages can be found by comparing them to the graph. Of course, the entire weight of the liver has to be divided out because a larger liver will have more space for liver glycogen. By doing this, the relative amount of liver glycogen could be found. The more liver glycogen a fish has, the more carbohydrates it has. The more carbohydrates that a fish has, the more food it was able to obtain and the more energy it has to get more food. This statistic reflects back on the overall environment of the marsh, specifically how much food is available to it. Salt marshes are a very important ecosystem, one where millions of life forms can exist in a very small area. One cubic meter of a salt marsh has more living activity that one cubic meter of the rain forest. Because of this, preserving them with tests and using standard curves is important to the world.
A standard curve is a graph that uses known solution concentrations to accurately predict unknown concentrations. A scientist may use this to find radioactivity, proteins (DNA) and other substances in a liquid. Varies assays of known concentrations are performed. Then, whatever property is being calculated, is placed on the best fit line of predetermined concentrations. This allows the researcher to accurately find the concentration of solute in each sample. A practical use for a standard curve is finding the amount of solid particles in rain. This would allow a scientist to evaluate the air’s health by seeing how much smog and unnatural pollutants are in the air. It may also assist in finding out how much ash a volcano releases into the air. After an eruption, the rain can be analyzed to see how much solid particles remain in the air, captured by the rain water. To do this the researcher would have to find or create samples of artificial ‘rainwater’ that has a known amount of dissolved solids. These controls would be assayed in a spectrophotometer. With the data, a standard curve can be created, showing not only the known concentrations but also helps determine the unknown samples. The graph is a more useful tool that perhaps a table of X and Y values. The table only shows the given values, whereas a graph can show values in between of the controls.
A standard curve is a tool used to find information you do not know using information that you do know. A graph with a best-fit line can be used in this way. For instance if you measured the ph of a substance and then measured that substances ph after you added 5, 10, 15 and so on drops of M HCI and made a graph with best-fit line you could predict what the ph would be after adding 7 drops of M HCI even though you never actually measured the ph after 7 drops. So standard curve is a way to find a variable that you haven’t even tested.
A standard curve is a way of measuring a concentration of a substance using assay data. The experiment uses variouos data from known concetrations and unknown concentrations. A Standard curve experiement generally measures absorbance, optical density, luminescence, fluorescence, and radioactivity. The data of the known concentrations is then plotted. The data from the unknown concentrations is plotted, then a line is drawn up to intersect the standard curve made from the known concetrations. Once an intersect point is made, the concentration of the substance is then known.
This can be applied to real life in several ways. one example is knowing the concentration of salt in a lake to see if it is too high or too low. Salt level concentrations can be made, and then compared to the levels in the lake. The standard curve can be applied to almost any experiment.
a standard curve is a semi-accurate way to predict how two or more objects will react with one another. this is by using know data and applying it to unknown data. for example if you were to take a sample of water without food coloring, and a sample of water with a known ammout of food coloring in it and put it thgrough a specrafatamiter hooked up to a computer to find the strandard curve you would be able to create a line graph. with multiple samples you could create a standard curve. after said multiple samples are puit in to the computer the unknown could be put in the spectrafatamiter and by compareing it to the other smaples the computer could tell where on the standard curve it fell. this can be applied to and used in many sientific experiments. it could be used to predict the ammout of time it would take that big mac rapper that you just threw out your window to decompose or to tell you the ammount of oxogen molicules in the atmosphere at ten thousand eleven hundred and two feet. all in all it is a very versitile instranment and can be applied in a multitude of ways this amkes it ideal for most any data representation.
that long enough?
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