Paper color layer analyzer is a useful technique in the separation and identification of various plant pigments. In this technique, the mixture comprise the pigments to it is in separated is first applied as a spot or a line to the document about 1.5 centimeter from the bottom sheet of the paper. The document is then placed in a container with the pointer of the file touching the solvent. Solvent is took in by the record and moves up the document by capillary action. Together the solvent crosses the area containing tree pigment extract, the pigments dissolve in and also move v the solvent. The solvent carries the liquified pigments together it moves up the paper. The pigments are lugged along at different rates due to the fact that they are not equally soluble. Therefore, the less soluble colours will move slower up the file than the much more soluble pigments. This is known as arising a chromatogram.

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record chromatography is useful for identifying unknown compounds - often used in crime step investigations to complement ink, lipstick, or fancy fibers. Over there are plenty of examples the chromotography in ~ This set-up shows two different pen inks.

Purpose: To recognize plant pigments by separation and isolation of the pigments utilizing thin layer record chromatography.

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The distance traveled bya details compound deserve to be offered to determine the compound. The ratio of thedistance travel by a link to that of the solvent prior is well-known as charcoal value; unknown compounds may be established by comparing your Rf"s to theRf"s of known standards.

Rf equation:

Rf = street traveled by compounddistance traveled by solvent

1. Cut a strip of coffee (or filter paper). Attract a horizontal line with a pencil (not pen) about half an customs fromthe bottom. Location a spinach leaf on the line and roll a penny end it so thatyou gain a heat of environment-friendly pigment ~ above the filter. Making use of a different component of theleaf, role the coin again over the same line. Repeat this procedure until present is relatively dark.2. Put about an inch of acetone in the beaker (isopropyl alcohol will likewise work.) 3. Tape the top of the coffee filter piece to a pencil and also balance the pencilacross the optimal of the beaker. See the image below for the set-up.4. It is very important that the bottom that the filter strip is in the acetone,but the environment-friendly spot is no in the liquid. If the acetone touch the spotdirectly, the colors will simply dissolve away.

5. Watch what wake up to the liquid in the beaker and also the clues on the filter paper. Results will take around 20 minutes.

6.Optional: repeated using other pigments - shot lipstick, felt reminder pens, cones candy..etc



1. Assign a band numberfor every pigment band - you need to see greens, yellows, oranges..etc.

BandColorPlantPigmentDistance(mm)Rf(use formula)
Yellowto Yellow-orangeCarotene
BrightGreen come Blue GreenChlorophylla
YellowGreen to Olive GreenChlorophyllb

2. Explain how a crime lab can use record chromatography to recognize if lipstick uncovered at a crime step matched the lipstick the a suspect.


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