The beam is perpendicular to the surface of the cuvette holding the liquid. Thanks!Borek said:How does the beam hit the surface of the liquid? At what angle?
It is not going to refract if the incident beam is perpendicular to the surface. Changes in refractive index will change the reflection though.Ella98 said:The beam is perpendicular to the surface of the cuvette holding the liquid. Thanks!
Will changes in reflection affect my absorbance measurements? I just want to know if the changes in refractive index will affect my absorbance measurements. Thanks, Hayao.HAYAO said:It is not going to refract if the incident beam is perpendicular to the surface. Changes in refractive index will change the reflection though.
[tex]R=\left |\frac{n_{1}-n_{2}}{n_{1}+n_{2}} \right |^{2}[/tex]
HAYAO said:It might be nice if you could attempt a reflectivity calculation on your own of the case where there is only water in the cuvette, and then think about how much that changes when there is a sample dissolved in it. Don't ask for "do it for me". Try your own attempt and we'll guide you.To start you off, look up refractive index for air, water, and cuvette (most likely made of quartz). And then put the numbers in the Frensel reflectivity equation above for both intersection, namely air-quartz and quartz-water. At this point, you will have to make an assumption based on these numbers whether you can neglect multiple reflection (reflection of a reflection of a reflection of a...) or not. Then calculate how much of the initial light passes through the cuvette with water. (Note: we have four intersection in total, i.e. two quartz walls.)
If you have done that, then make a reasonable estimate of how much the refractive index of the water changes when you have something dissolved in it. Contemplate how much that would affect the reflectivity.
And that's not what I meant, neither.Ella98 said:I'm sorry I didn't mean with my reply to imply I wanted you to do any calculations for me. I just thought what I asked was a yes or no question. I didn't know calculations will be required to answer it. Thanks for the help! I really appreciate it.
UV-Vis spectroscopy is a technique used to measure the absorption and transmission of light by a sample in the ultraviolet and visible regions of the electromagnetic spectrum. It is commonly used to analyze the chemical composition and concentration of a substance.
UV-Vis spectroscopy measures changes in refractive index by analyzing the absorption of light by a sample. When light passes through a sample, it may be absorbed by the molecules present. The degree of absorption is related to the refractive index of the sample, which can then be calculated using mathematical equations.
UV-Vis spectroscopy can be used to analyze a wide range of samples, including liquids, solids, and gases. It is commonly used in the fields of chemistry, biochemistry, and environmental science to study the properties of various substances.
UV-Vis spectroscopy has many applications, including determining the concentration of a substance, identifying unknown compounds, and studying chemical reactions. It is also commonly used in quality control and research and development in industries such as pharmaceuticals, food and beverage, and cosmetics.
UV-Vis spectroscopy is a relatively simple and fast technique compared to other analytical methods. It also has a wide range of applications and can provide quantitative and qualitative information about a sample. However, it may not be suitable for samples with high levels of turbidity or fluorescence, and it may not provide information about the structure of a compound like other spectroscopic techniques such as infrared spectroscopy.