Quantitative analysis with UV-1900i standalone operation

This video gives a simple explanation on quantitative measurement based on the Beer-Lambert Law. It will also demonstrate a simple quantitative analysis using UV-1900i standalone operation.
In this video, we will go through the standalone operation on quantitation mode for UV-1900i.
In Ultraviolet-visible spectroscopy, quantitation is usually performed on a major peak of the sample.
When incident light passes through a sample, the sample in the cuvette absorbs the light. The amount of light that is not absorbed by the solution, will come out as transmitted light. Transmittance is the ratio of the intensity of the incident light beam to the intensity of the transmitted light beam,and is commonly expressed as a percentage. If there is no absorption of the light passing through the solution, the transmittance is 100%.
Absorbance is used in U V-visible spectroscopy, to indicate the amount of absorbed light.
It is defined as A equals to log one over transmittance.
The relationship of absorbance to concentration is given by Beer-Lambert Law.
It can be expressed as shown in the equation, where A is the absorbance, L is the optical path length, that is the length of the cuvette cell, c is the concentration of the analyte, and E is the molar absorptivity or extinction coefficient, which is constant for a particular analyte at a specific wavelength.
If the absorbance of a series of solutions of known concentration are measured, a linear calibration graph of absorbance versus concentration could be obtained, if the Beer-Lambert Law is obeyed.
The Beer-Lambert law states that, the absorbance, of an analyte in solution, is proportional to its concentration, for a fixed path length.
The concentration of an unknown sample solution can be determined by measuring its absorbance and quantified using its calibration curve.
Now, lets look at how the UV-1900i conduct a quantitation analysis.
From the mode menu screen, we will select quantitation.
Under formula, set the formula for quantitation.
For this example, 1 wavelength is selected.
We will key in the wavelength used for quantitation,and select apply.
Under Calibration Curve settings tab, set the method of calibration curve creation.
Normally, multi point curve method is used.
So this is used as an example.
Set the number of standard samples for calibration curve creation under number of samples.
Set the order of calibration curve.
One is selected which represent a linear curve.
Select the concentration unit for measurement result.
Select edit sample name tab to input the sample name and number if required.
Now, we will select attachments.
Since we will not be using any attachment, we will proceed to standard table.
Enter the concentration value of each standard sample to be measured.
Select measure cell one for standard sample absorbance reading.
Now, Place the cuvette containing blank reagent into both sample and reference cells of the sample compartment.
Select auto zero to zero the blank reagent.
Once auto zero is finished, replace the blank reagent with the standard sample for the sample cell.
The cuvette in the reference cell remains as it is.
Select start to measure the first standard sample.
The absorbance value of the standard sample is displayed on the standard table.
Measure the remaining standard samples.
After the standard sample measurement is completed, select calibration curve to view the curve.
Select Calibration curve statistical function to view calibration curve equation.
Next, replace the standard sample with the unknown sample for the sample cell.
The cuvette in the reference cell remains as it is.
Select start to measure the sample’s absorbance.
The unknown sample’s absorbance and concentration value are displayed in the table.
That is how quantitation measurement can be done on the UV-1900i standalone operation.
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