Table of Contents
- 1 Why is it important to place the cuvette into the sample holder in the same orientation every time?
- 2 What will happen if you place the cuvette in the spectrophotometer incorrectly?
- 3 Why is the cuvette to be handled along the opaque sides?
- 4 Why is it important not to have fingerprints on the cuvette?
- 5 Why is it important to only touch the rigid or frosted sides of the cuvettes when doing spectrophotometer?
- 6 How does cuvette affect absorbance?
- 7 Why was it important not to touch the cuvette with your fingers?
- 8 Why is it important to only touch the rigid or frosted sides of the cuvettes when doing spectrophotometry?
- 9 What is the difference between a spectrophotometer and a cuvette?
- 10 Do I need a quartz cuvette for my UV spectrophotometer?
- 11 Can plastic cuvettes be used for UV reading?
Why is it important to place the cuvette into the sample holder in the same orientation every time?
You will notice that the cuvette has a vertical white line on it; make sure that line is aligned with the notch or groove on the rim of the sample container. This keeps the cuvette in the same orientation every time, so any imperfections in the glass will not affect your results.
What will happen if you place the cuvette in the spectrophotometer incorrectly?
On a spectrophotometer which measures how much light is absorbed, it is safe to say that less light will reach the sample in a dirty cuvette. Therefore, the machine will interpret this as more light being absorbed. So, in other words, if the cuvette is dirty, the readings will be off.
What direction should the cuvette face when placing it in the spectrophotometer?
Cuvettes must be carefully placed and removed from spectrophotometers and fluorometers. When inserting the cuvette, hold the cell at the top and make sure the engraved letters of the cuvette are facing the light source of your machine. The cuvettes should be pushed straight down into the cuvette holder.
Why is the cuvette to be handled along the opaque sides?
Handle the cuvettes carefully to avoid breakage. Hold the cuvettes in such a manner that, opaque sides are held between two fingers & transparent sides are not being touched.
Why is it important not to have fingerprints on the cuvette?
Wipe the cuvette with a Kimwipe to remove any liquid and fingerprints on the outside of the cuvette. Both of these will interfere with light transmission and will cause erroneous readings. This technique prevents scratching of the cuvette in those areas through which the light will pass.
How do spectrophotometers help us determine what kind of molecule is in a solution?
The object in using the spectrophotometer is to measure the O.D. due to the presence of a specific molecule in a solution. But this molecule may be mixed with other molecules which also absorb light at the same wavelength. To negate such contributions to absorbance, the machine is arbitrarily set to read O.D.
Why is it important to only touch the rigid or frosted sides of the cuvettes when doing spectrophotometer?
The purpose of the frosted faces is to prevent light scattering out of the cuvette at the sides for certain types of samples. Cloudy samples tend to scatter light. The frosted sides help to prevent the scattered light signal being lost and giving innaccurate readings.
How does cuvette affect absorbance?
A cuvette (with fingerprints on it) will give a slightly higher absorbance reading and the measured concentration will be significantly higher than the actual concentration.
How do spectrophotometers help us determine the concentration of solution?
A spectrophotometer is an instrument that measures the amount of photons (the intensity of light) absorbed after it passes through sample solution. With the spectrophotometer, the amount of a known chemical substance (concentrations) can also be determined by measuring the intensity of light detected.
Why was it important not to touch the cuvette with your fingers?
Wipe the cuvette with a Kimwipe to remove any liquid and fingerprints on the outside of the cuvette. Both of these will interfere with light transmission and will cause erroneous readings. 6.
Why is it important to only touch the rigid or frosted sides of the cuvettes when doing spectrophotometry?
Why is it important to wipe the cuvette before every measurement?
Proper cuvette cleaning is very important. The residue from previous experiments can result in poor performance, inaccurate measurements and will waste your time and your sample. If the cuvettes are stored wet , they may dry with sample material on the measuring surfaces, which will effect subsequent measurements.
What is the difference between a spectrophotometer and a cuvette?
A spectrophotometer is an ideal choice for measuring materials of interest light absorbance or transmittance to a specific spectrum wavelength, in this way to get data on substance concentration and purity. A cuvette is a small vessel containing samples used for spectroscopic measurements which are placed in the spectrophotometers.
Do I need a quartz cuvette for my UV spectrophotometer?
For UV experiments, you absolutely need an ES quartz cuvette and it’s highly recommended that you do not try to cut corners here because by getting a cheap UV cell, your data will not be up to par. 3. IR Quartz is an amazing choice for cuvettes for UV-vis range measurements.
What is the purpose of the frosted sides of a spectrophotometer?
The purpose of the frosted faces is to prevent light scattering out of the cuvette at the sides for certain types of samples. Cloudy samples tend to scatter light. The frosted sides help to prevent the scattered light signal being lost and giving innaccurate readings.
Can plastic cuvettes be used for UV reading?
If you use the standard plastic cuvettes (although you can get UV safe plastic cuvettes) in the UV range the plastic will absorb some of the light so you won’t get a correct reading.