What is kbr pellet

Sample should be transparent to IR radiations so it allows the radiations to pass through them. So salts like KBr, NaCl, AgCl are used for mixing of sample in order to obtain the accurate IR spectrum of a sample with sharp peaks, good intensity with high resolution. For powdered samples one of the way is to disperse it in Infrared Transparent medium such as Potassium Bromide KBr by pressing it into disc.

While 7 mm pellet for FTIR applications for as little a 2 tons. Though various techniques for the sample preparation exists here we will discuss the Pressed pellets Technique for solid samples.

Clean the mortar and pestle with chloroform or acetone thoroughly to get rid of any dirt and dry them with tissue. Transfer a speck of sample into the mortar. Be careful of not adding too much sample which may cause over saturation. Scoop out dry KBr into the mortar. Grind using the pestle. The difference between the two spectra results from ion exchange between chloride ions and bromide ions when a hydrochloride sample is diluted by KBr. While not shown here, the single-reflection ATR attachment can obtain a spectrum equivalent to the KCl pellet method, without pretreatment.

The blue line is the spectrum immediately after forming the pellet, the red line was measured after 2 minutes, and the green line was measured after 10 minutes.

In addition, it can be seen that the peak near cm -1 gradually shifts toward the low-wavenumber end. This also indicates a gradual ion exchange when L-cysteine hydrochloride is analyzed using the KBr pellet method.

The Japanese Pharmacopoeia prescribes the KCl pellet method for the analysis of diphenhydramine hydrochloride, instead of the KBr pellet method. The intensity increases as the mass increases. In accordance with the Beer-Lambert law absorbance increases linearly with the pellet mass which is proportional to pathlength.

This gives the operator control over the peak intensities. When attempting to identify weak bands, possibly from trace contaminants, KBr pellets offer clear advantages with substantial improvements in limits of detection. No peak intensity correction required in ATR spectroscopy the effectively pathlenth is dependent on the wavelength, resulting in changes of the relative band intensities and, for wide bands, in a shift of the absorption maximum A variety of commercial spectra libraries.

Further information Contact Request further information Related products. Further information. Preparation of pellets Generally, it is easy to produce a good quality KBr pellet if an evacuable pellet die is used correctly. Good to know — Possible faults and remedy However, some faults in the produced sample pellet may occur due to a variety of reasons. Fault Cause Remedy Sample pellet not clear. Lacks optical clarity. To ensure that a sample pellet is produced which will enable accurate spectra of samples to be obtained, it is essential that the sample is thoroughly blended with the halide salt powder.

Blending can be achieved either by using a mortar and pestle or by using a grinding mill such as the Specamill. If a pellet breaks apart, then possibly not enough total mixture is being used in the die. Under compression the disc has become too thin and fragile.