activity 2 detection of common elements in drug samples

ACTIVITY NO. 2DETECTION OF COMMON ELEMENTS IN DRUG SAMPLES

//rgd13 Pharmacy and Chemistry of Medicinals II

Elemental analysis – experiment that determines the amount (typically a weight percent) of an element in acompound The most common type of elemental analysis is for carbon, hydrogen, nitrogen, and heteroatoms (CHNXanalysis).

- type of analysis useful for organic compounds (compounds containing carbon-carbon bonds)- important to help determine the structure of an unknown compound, as well as to help ascertain the structure

and purity of a synthesized compound2 Ways: 1. QUANTITATIVE: determine how much of each element are present

2. QUALITATIVE: determine what elements are present

PRINCIPLES INVOLVEDASPIRIN

(acetylsalicylicacid)

PARACETAMOL(acetyl-para-aminophenol)

SULFONAMIDE

1.Test foracidity &alkalinity

Indicators reacted to the sample dueto the presence of H3O+ and OH-

Blue litmus → Red litmus : acidicRed → Blue: Basic

B → R R → B

B → R (weaklyacidic (pKa ̴5–8)due to thepowerfulelectron–withdrawingeffect of the–SO2– substituent& stabilization ofthe resulting anionby resonance)

2.Test forH and O

Liberation of H and O resulting tothe presence of moisture inside (onthe sides) the test tubes

Presence ofmoisture (+)



3.Test forC

Presence of black residueas product of incompletecombustion of hydrocarbons

Black Residue(+)

Black Residue (+) Black Residue (+)

4.Test forN

N is basic in nature and yieldsammoniated odor

a. R → R (–)b. burnt sugar

a. R → B (+)b. pungent odor

a. R → B (+)b. pungent odor

5.Test forHalogen

a. Beilstein Test: Formation of sootduring the combustion indicatesaromatic compounds.Organic chlorides – deep greenbromides – bluish with a green atedge

A green flash is indicative ofchlorine, bromine, and iodine,but NOT fluorine.

Yellow (–) Yellow (–) Yellow (–)



b. tests for halide ions using silvernitrate solution followed byammonia solution

IonPresent Observation

F- no precipitateCl- white precipitate

Br- very pale creamprecipitate

I- very pale yellowprecipitate

NR NR NR

6.Test forphenolandbenzene

a. Millon’s Test:Phenolic amino acids (Tyrosine andits derivatives) respond to this test.Compounds with a hydroxybenzeneradical react with Millon’s reagentto form a red colored complex.Millon’s reagent is a solution ofmercuric sulfate in sulfuric acid.

NRRed (+) NR

b. Ferric chloride Test:Compounds with a phenol groupwill form a blue, violet, purple,green, or red-brown coloration

Equation3ArOH + FeCl3 → Fe(OAr)3 +3HCl

yellow color (-)

determines thepurity of aspirinFeCl3 + phenolgroup = purplecomplexIf salicylic acid

(a phenol) ispresent(impurity) theproduct will turnpurple

Blue/Violet–bluecolor (+)

blue, violet,purple, green, orred-brown color(+)

7.Test forS and P

P + HNO3 → PO4- liberates to react

with ammonium molybdate →ammonium phosphomolybdate(yellow precipitate)

S + HNO3 → H2SO4 + BaCl2 →BaSO4 (white precipitate)

NR NR White ppt

NR = No Reaction



Drugs containing Sulfur1. Sulfamethoxazole (Bactrim®)2. Gliclazide (Diamicron MR®)3. Acetazolamide (Diamox®)4. Celecoxib (Celebrex®)5. Furosemide (Lasix®)

Drugs Containing Phosphorus1. Dibasic Sodium Phosphate (Fleet

Enema®)2. Alendronate (Fosamax®)3. Foscarnet (Foscavir®)4. Citicoline (Cholinerv®)5. Risedronate (Actonel®)

Drugs Containing Halogens1. Cefaclor (Xelent®): Cl2. Vancomycin (Vancocin®): Cl3. Chlorpromazine (Thorazine®): Cl4. Levothyroxine (Eltroxin®): I5. Ipratropium Br (Atrovent®): Br

Drugs Containing Nitrogen1. Theophylline (Nuelin SR®)2. Na Nitroprusside3. Glyceryl Trinitrate (Deponit NT 5®)4. Ceftriaxone (or any Cephalosporin)5. Phenobarbital (or any Barbiturates)

Drugs Containing Phenyl1. Aspirin2. Paracetamol3. Morphine4. Ibuprofen5. Atorvastatin (Lipitor®)

Drugs Containing Oxygen1. Omeprazole (Risek ®)2. Amlodipine (Norvasc®)3. Amoxicillin (Himox®)4. Azithromycin (Zithromax ®)5. Diazepam (Valium®)

activity 2 detection of common elements in drug samples

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