Hopkins-Cole Test

Hopkins-Cole Test is used to detect the presence of tripthopahan.
The reagent contain glioksilic acid. Positive reaction will show purple color (ring) in the solution boundaries. The purple color occur by condensation of 2 core of tripthophan to glioksilic. This test can't succes if there are strong ocsidator like nitrat and clorat. Sulphuric acid that used must very pure, it is means that there aren't other matter which will be an ocsidator.

Procedure:
1. Take 2 ml of solution that will be tested in the test tube
2. Add with 2 ml of Hopkins-Cole reagent
3. Add H2SO4 from the wall of the test tube
4. Wait some seconds
5. See the color of solution.

Millon Test

Milon test is chemical reaction to detect the presence of tyrosine.
It is specific reaction to monophenol derivative as tyrosine. In this test we use mercury ion in the nitric acid. Positive test will  show red color in the solution. The red color formed of salt from tyrosine nitration. Hidroxiphenil from tyrosine will react to Hg from millon reagent to produce red color.

Method to make millon reagent:
1. Take 2,5 gram of mercury sulphat and add with 5 ml HNO3
2. Add solution with 15 ml of aquadest

Procedure:
1. Take 2 ml of solution that will be tested in the test tube
2. Add the solution with 5 drops of millon reagent
3. White floe will seen, heated carefully
4. See the color of solution.

Xanthoproteic Test

Xanthoproteic test is used to detect the presence of tyrosine, phenilalanine, and tripthophane.
Benzene core in the amino acids above will be nitrated with HNO3 and forming nitro compound, the yellow color is formed and in the alchaly environment will change to orange color.

Important in this test is:
1. HNO3
2. NaOH

Procedure:
1. Take 2 ml of solution that will be tested in the test tube
2. Add 1 ml of HNO3
3.  Look at the white pecipitate that formed
4. Boiled up ,the precipitate will dissappeared and will show yellow color of solution
5. Add NaOH drop per drop
6. The orange color will appear

Ninhidrin Test

Ninhidrin test is chemical test to detect the presence of amino acids.
All kinds of amino acid can detected with this test. Amino acid reacted with ninhidrin (triketohidrindenhidrat) to forming aldehide and release Nh3 and CO2. In this reaction also formed blue color (but prolin and hidroxiprolin will show yellow color). The blue color is reaction of 2 molecule of ninhidrin with NH3. It is the signing of positive result for this test.

Procedure:
1. Take 2 ml of solution that will be tested to the test tube
2. Add with 5 drops of ninhidrin solutions
3. Boiled in 10 minutes
4. See the color of solution.

Biuret Test

Biuret test is chemical test to detect the presence of proteins, especially the presence of peptide bond.
Peptide bond is bonding each amino acids in the protein. Biuret can't detect the single amino acids, because there aren't peptide bond in it. Positive result will showing purple color, Cu++ will reacting with NH from peptide bond and O from water and show the purple color of solution. Long proteins show purple color, short proteins show pink color.

Important in this test is:
1. NaOH 10 %
2. CuSO4 0,1%

Procedure:
1. Take 2 ml of solution that will be tested to the test tube
2. Add with 2 ml of NaOH and 10 drops of CuSO4
3. See the color of solution.

Protein Test

Proteins is polymer of amino acid which conected by peptide bond. There are 20 amino acids that arrange the proteins, the differ of protein has differ amino acids composition. Bellow you will see some test to detect proteins or certain amino acid.
1. Biuret test: to detect the presence of proteins, actually the presence of peptide bond
2. Ninhidrin test: to detect the presence of amino acids
3. Xanthoproteic test: to detect the presence of tyrosine, phenylalanine, and trypthophane
4. Milllon test: to detect the presence of tyrosine
5. Hopkins-Cole test: to detect the presence of trypthophan.

Iodium Test

Iodium test/Lugol test is chemical test to detect the presence of amylum.
Amylum presence in many kinds of food, example: rices, corns, pottatoes, sweet pottatoes etc. The are two strains of  amylum chains, they are: amylose ( long and straight chains ), amylopectine ( long and branched chains). Tested amylose with iodium will show blue color, but amylopectine will show purple color.

Procedure:
1. Take 3 drops of amylum solution and add 1 drop of iodium solution
2. See the color of solution

Carbohidrate Test

The are many test to detect the presence of carbohidrate (monosaccharide, disaccharide, amylum, etc). Below you will see some test to carbohidrate, you can see detailed explanation when you click it.
1. Molish Test: to detect the presence of all kinds of carbohidrate
2. Benedict Test: to detect the presence of monosaccharide and reduction sugar
3. Seliwanof test: to detect the presence of ketose sugar
4. Barfoed Test: to differ the monosaccharide and dissaccharide

Barfoed Test

Barfoed Test is used to differ upon monosaccharide and disaccharide.
Monosaccharide reducting copper solution in the acid environment, forming red-brown or brown-orange pellet. In the more time heating, reduction disaccharide will show the same color.

Method to make baffoed reagent:
Mix 13,3 gram of copper acetat in the 200 ml of water and add 1,8 ml acetic acid glacial.

Procedure:
1. Take 1 ml solution that will be tested in the test tube
2. Add 2 ml of barfoed reagent
3. Boiled precise 1 minute, wait until pellet appear
4. See the color of pellet.

Positive Test:

Seliwanoff Test

Seliwanof Test is a chemical test to detect the presence of ketose sugar.
This test specific to ketose sugar. The basis of teory of the test is formed 4-hidroximetil furfural which reacted with resorsinol (1,3-hidroxibenzene) forming the compound with red color. Glucose can gives cerry red color in the longer time heated. In the high concentration, glucose and another sugar will gives the same color.


Method to make seliwanoff reagent:
dissolve 0,5 gram of resorsinol in the 100 ml of alcohol and add with 5 N HCl.


Procedure:
1. Take 0,5 ml solution which will be tested in the test tube
2. Add 5 ml of HCl
3. Boiled aproximately 10 minutes
4. Look the color of solution.


Reaction:

Positive Test:

Courtesy of en.wikipedia.org

Benedict Test

Benedict Test is a chemical test to detect the presence of monosaccharide and reduction sugar.
Sugar which have aldehide will react with alkali  copper solution to forming cuprokside that colored. Positive reaction happen if the solution color is green, orange-red or red and green, yellow, or red sediment.


Method to make benedict reagent:
1. Dissolve 173 gram Natrium citrat and 200 gram Sodium karbonat (christal) in the 800 ml aquadest, heated to improve reaction rate
2.Filter the solution
3. Dissolve 17,3 gram of cupri sulphat in the 100 ml aquadest, pour to the first solution slowly. Stir continuously, waiting until the solution cold and then add aquadest until the solution reach 1 L.


Procedure of the Test:
1. Take 0,5 ml of solutions which want to be tested in the test tube
2. Add with 5 ml of benedict reagent
3. Boiled aproximatelly in 2 minutes
4. Look at the solution color
5. Waiting until sediment arising out, look at the sediment color.

Result:

Courtesy of www.jce.divched.org

Molish Test

Molish Test is a chemical test to detect the presence of carbohidrate. It is not specific test, all of the member of carbohidrate (C6H12O6) can be detected. It is also detect carbohidrate in free form or in attached form. Positive result of this test is appear of purple color. Carbohidrate will be dehidrate by strong acid to form furfural, alpha-napthol will react with furfural to produce purple color. Alpha-napthol present in the molish reagent.


How to make molish reagent:
To make molish reagent we must mix 10 gram of alpha-napthol to 100 ml of 95% etil alcohol.


Procedure of the Test
1. Take 2 ml of solution that want to be tested in the test tube
2. Add 2 drops of molish reagent
3. Mix the solution
4. Take 2 ml of sulphuric acid (H2SO4) and pour to the first solution through the wall of test tube.
5. Positive result will showing purple color ring in the solution boundaries.

Disscusion

                                                        Courtesy of en.wikipedia.org



Positive Test Result

Courtessy of www.demochem.de