Question

UV/Vis spectrophotometry

1) What is the meant by slit width and spectral bandpass?

couple of sentenses in your own word for credit

2) in the section of the color by spectrophotometry, what type of the cell material should be emplyed? why?

couple of sentenses in your own word for credit

Answer 1

1) Slit width is the width (usually expressed in mm) of the entrance and exit slits of a monochromator. The slits are rectangular apertures through with light enters into and exits from the monochromator. Their purpose is to control the spectral resolution of the monochromator, that it, its ability to separate close wavelengths. In the diagram below, B is the entrance slit and F is the exit slit.

A bandpass filter is an electronic device or circuit that allows signals between two specific frequencies to pass, but that discriminates against signals at other frequencies. Some bandpass filters require an external source of power and employ active components such as transistors and integrated circuits; these are known as active bandpass filters. Other bandpass filters use no external source of power and consist only of passive components such as capacitors and inductors; these are called passive bandpass filters.

2) Samples for IR spectrophotometry may be smeared between two discs of potassium bromide or ground with potassium bromide and pressed into a pellet. Where aqueous solutions are to be measured, insoluble silver chloride is used to construct the cell.