How do you clean IR salt plates?

Cleaning salt plates: In the fume hood, using the halogenated waste bottle with a plastic funnel inserted into the top, place a salt plate into the funnel and rinse it with a little dichloromethane (methylene chloride). Allow it to dry (this is quick) and remove it by handling the edges of the salt plate only.

What if any precautions must you take when using salt plates for IR sample preparation?

Rule 1: ONLY clean NaCl plates with dichloromethane (aka, methylene chloride, CH2Cl2) and cyclohexane (C6H12). NEVER use water (H2O) to clean a salt plate as it will ruin the plate, permanently! Rule 2: NEVER hold the shiny side of a plate between your fingers (to avoid fingerprints). ONLY hold it by the edges.

Why is NaCl and KBr used in IR spectroscopy?

Although KBr is more expensive than NaCl, KBr has some advantages over NaCl. By using KBr crystal the measurement is possible over the range of 4000-400cm-1. NaCl starts to absorb IR from 650 cm-1.

Why we are using KBr for IR blank?

Potassium bromide (KBr, spectroscopic grade) is typically used as the window material because it is transparent in the IR, between 4000–400 cm-1. Alternatively, samples can be contained within a KBr matrix and pressed to form a pellet that is then analysed.

Why is it important to keep the IR salt plates dry?

Moisture in the air causes salt plates to become cloudy; moisture on your fingers causes prints (see above). We store them in desiccators to prevent them from becoming cloudy. Salt plates are very fragile and will chip or shatter if you drop them.

Why is water not used as solvent in IR?

Water cannot be used as a solvent for ir spectroscopy because: 1- Water has two strong infrared absorption peaks. 2- Water is a strongly polar solvent that dissolves the alkali halide disks commonly used for IR.

Why are salt plates used in IR rather than glass?

Sodium chloride (NaCl) cells are transparent to IR and do not absorb the infrared radiation in the region between 4000-450 cm-1; hence it is used to analyze the sample in IR.

Why are salt plates used in IR?

Care and Handling of IR Plates. Sodium chloride is chosen because it is transparent to infrared radiation. These plates – called “salt plates” – are rather expensive because each plate is cut from a single giant crystal; they are very fragile and sensitive to moisture, including the moisture in your fingers.

What is difference between FTIR and IR?

FTIR spectrometers have several prominent advantages: (1) The signal-to-noise ratio of spectrum is significantly higher than the previous generation infrared spectrometers. (2) The accuracy of wavenumber is high. Due to these advantages, FTIR Spectrometers have replaced dispersive IR spectrometers.

Why is it important to wear gloves when handling salt plates?

Alternatively, you can wear gloves when you handle salt plates, as long as the gloves are dry. Moisture in the air causes salt plates to become cloudy; moisture on your fingers causes prints (see above). We store them in desiccators to prevent them from becoming cloudy.

Does water affect IR?

Presence of water in sample significantly distort IR spectrum of compound. Moreover, KBr and ZnSe optical acessories (prism, beam splitter) used in IR spectrometer are also water sensitive, it can permanently damage them.

What is a salt plate?

This plate is sourced from natural salt deposits found in the Himalayas. The dense crystalline composition adds complex flavor to all types of foods. Heat on the grill to sear seafood and meat, or chill for serving a selection of fruits, vegetables and cheeses with a hint of salt.

What kind of IR plates are used in organic chemistry?

The IR plates that you use in the organic chem labs are made of polished sodium chloride. Sodium chloride is chosen because it is transparent to infrared radiation.

What are the problems with damaged salt plates?

The samples of damaged salt plates in Figure 4.2. 6 show common problems associated with use or potentially mishandling. Clouding, and to an extent, scratches can be polished out with an iron rouge. Areas where the crystal lattice is disturbed below the surface are impossible to fix and chips cannot be reattached.

How to make salt pellets for IR spectroscopy?

Place the salt pellet mixture into the other opening of the nut and level by tapping the assembly on a countertop. Screw in the second bolt and place the assembly on its side with the bolts parallel to the countertop. Place one of the wrenches on the bolt on the right side with the handle aiming towards yourself.

Do you have to resurface an IR plate?

IR plates can be resurfaced, so don’t throw away a plate if it looks bad. Two different methods are used to prepare thin films on an IR plate. If the compound to be studied is a liquid, you need to use thin-liquid film IR sampling technique.