Page 23 - Instrumental Analysis - Pharm D Clinical- 07-PA403

UV-visible Spectrophotometry

I- Filters

• Made from colored glass or a dye
suspended in gelatin and sandwiched
between glass plates.

• They transmit a wide band of 35-50 nm
which is not exactly monochromatic.

• They act by selective absorption of
unwanted λ and transmitting the
complementary color which is needed
to be absorbed by the sample to be
analyzed.

• Filters are the simplest form of
monochromators. They are inexpensive
however they are restricted to the
visible region.

41

ROY G BIV
Red Orange Yellow Green Blue Indigo Violet

42

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