1901: Secret Service Established

Counterfeiting In 1865, 1,600 different forms of currency in U.S. The amount of counterfeit currency increases 25% year

Preventative Measures

Paper-Based Identification of Counterfeiting Only one company in U.S. can make paper for currency Cellulose based paper w/red & blue threads Most other papers are stiffened by adding starch

Cellulose v. Starch Identification

Glycosidic Linkage

Functional Groups

Identification Of Unknowns Since 1995, many commercial chemical products have had a chemical “signature” mixed in to assist in their identification Unique functional groups and structures allow chemists to identify the date, source and purchaser of the chemical

Lab: Using Organic Indicators Purpose: To determine the specificity of four organic indicators and to apply them to the identification of unknown solutions

Chemistry of Organic Indicators Benedict’s Reagent: Copper ions in solution oxidized to cupric oxide, causing color change Lugol’s Solution: Potassium iodide sits in spaces between monomers, blocking out light, causing color change Biuret Reagent: Copper ions in solution reflect off of the amide functional group, causing color change Sudan IV: Molecules of dye bind to organic molecule based upon solubility

Protocol 1: Setup Obtain 5 test tubes and fill 1 with 5mL of water Mark the other tubes w/ a grease pencil to the same level Fill the remaining 4 tubes with 5mL of 1% starch, 1% glucose, 1% gelatin and 1% lipid respectively

Protocol 2: Benedict’s Test In the first test, add 5 drops of Benedict’s Reagent to each tube Place all four tubes in a hot water bath The first one to change color is the organic molecule for which benedict’s reagent is an indicator

Protocol 3: Lugol’s Test Clean up the tubes and restock with your standard solutions (water, 1% starch, etc.) Add 5 drops of Lugol’s to each tube NO HEATING IS NECESSARY The most drastic change is the organic molecule for which Lugol’s is an indicator

Protocol 4: Biuret Reagent Test Clean up the tubes and restock with your standard solutions (water, 1% starch, etc.) Add 5 drops of Biuret Reagent to each tube NO HEATING IS NECESSARY The most drastic change is the organic molecule for which Lugol’s is an indicator

Protocol 5: Sudan IV Test Clean up the tubes and restock with your standard solutions (water, 1% starch, etc.) Add 5 drops of Sudan IV Reagent AND 5 drops of Ethyl Alcohol to each tube Do not heat but shake up tube The most drastic change is the organic molecule for which Sudan IV is an indicator Note: This is a solubility- based test

Protocol 6: Identification of Unknown Mixtures Clean out your tubes and obtain 5mL of your 1 st assigned unknown in each of four test tubes Add 5 drops of Benedict’s to the first tube, 5 drops of Lugol’s to the second, 5 drops of Biuret to the third tube and 5 drops of Sudan IV & Ethyl Alcohol to the 4th Heat only the Benedict’s Record the changes and determine which of the four unknowns is present in that mixture Repeat this procedure for the two remaining assigned unknowns.

UNKNOWN MIXTURE ASSIGNMENTS Group 1 –Unknowns A, B, E Group 2 –Unknowns C, D and F Group 3 –Unknowns E, F and A Group 4 –Unknowns A, D, F Group 5 –Unknowns B, C and D Group 6 –Unknowns B, C and E