Calculating Log(MW) & MW with LINEST

  • Thread starter Biochemgirl2002
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    Biochemistry
In summary, the conversation discusses the process of finding the LINEST equation for a standard curve, using it to calculate log(MW) and MW, and determining the error on both values. The equation for finding the error on log(MW) is error on Rf multiplied by 1.392047709, while the equation for finding the error on MW is 10^(2.203) multiplied by the error on log(MW). The calculated error on log(MW) is 0.00695 and the calculated error on MW is 1.11Da.
  • #1
Biochemgirl2002
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1
I have found my LINEST equation for my standard curve, which is
where y=log(MW)
AND x= Rf
y=-1.392047709x+2.324113743

as well, my imageLab gives me:
Relative Front (Rf) = 0.087
error on Rf=0.005

I can calculate my log(MW) by inputing my Rf into x value of the equation
y=-1.392047709(0.087)+2.324113743
y=2.203

and my MW can be found by taking it out of log

MW = 10^(2.203)
MW=159.58Da

Now, I want to find my error on the log(MW) and MW,

i think this two part equation will work, but i am unsure

Screen Shot 2021-12-07 at 11.43.03 AM.png
Screen Shot 2021-12-07 at 11.43.15 AM.png
 
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  • #2
error on log(MW) = error on Rf * 1.392047709error on MW = 10^(2.203) * error on log(MW)error on log(MW) = 0.005 * 1.392047709error on log(MW) = 0.00695error on MW = 159.58 * 0.00695error on MW = 1.11Da
 

FAQ: Calculating Log(MW) & MW with LINEST

What is the purpose of calculating Log(MW) and MW with LINEST?

The purpose of calculating Log(MW) and MW with LINEST is to determine the molecular weight (MW) of a compound based on its logarithm (Log(MW)) and a set of experimental data. This can be useful in various scientific fields such as chemistry, biochemistry, and pharmacology.

What is the formula for calculating Log(MW) and MW with LINEST?

The formula for calculating Log(MW) and MW with LINEST is Log(MW) = intercept + slope * Log(MW) and MW = 10^(intercept + slope * Log(MW)), where the intercept and slope are obtained from a linear regression analysis using the LINEST function in Microsoft Excel.

What type of data is needed to calculate Log(MW) and MW with LINEST?

To calculate Log(MW) and MW with LINEST, you will need a set of experimental data that includes the Log(MW) values and corresponding MW values. These values can be obtained through various methods such as mass spectrometry, NMR spectroscopy, or chemical synthesis.

What are some potential sources of error when calculating Log(MW) and MW with LINEST?

Some potential sources of error when calculating Log(MW) and MW with LINEST include experimental errors in measuring the Log(MW) and MW values, assumptions made in the linear regression analysis, and limitations of the LINEST function in Excel. It is important to carefully consider these factors and validate the results with other methods.

How can the results of calculating Log(MW) and MW with LINEST be used in research?

The results of calculating Log(MW) and MW with LINEST can be used to identify and characterize unknown compounds, determine the purity of a sample, and assess the success of a chemical synthesis reaction. This information can also be used to predict the physical and chemical properties of a compound, which can aid in drug discovery and development.

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