AS245: Bachelor in Science Applied Chemistry Title: Analysis of Aspirin Tablet Course: Spectrochemical Methods of Analysis (CHM580) Name: Mohamad Nor Amirul Azhar b. Kamis Matrix no:
2014647344 (AS245 3S)
Date of experiment: 18th March 2015 Date of submission: 29th May 2015 Group members: 1. Nurnailah bt. Noorazlan 2. Nor Amirah bt. Ahmad Azuan 3. Noramira bt. Saad It is my responsibility as a student of UiTM to adhere to truthfulness and avoid dishonesty, fraud or deceit of any type in connection with write up and conduct of this experiment. Signature:__________ Date:
TITLE:
Analysis of aspirin tablet by using Fourier Transform Infrared (FTIR).
ABSTRACT: Background spectrum was scanned to avoid the interference from moisture or water and carbon dioxide. Three standards of caffeine, penachetin and acetylsalicylic acid (ASA) were scanned by using FTIR. The aspirin sample was analysed and followed by scanning and unknown (unknown A) to determine the functional group of all of them. All of the standards and sample were analysed by using pelleting method which is the mixing between the solid of standard with KBr to make a pellet to be analysed. The bonds appear in each of standards, sample and an unknown were tabulated in tables. It is proven that the unknown is the salicylaldehyde (C 7H6O2) with transmitted signals at 2834.15cm -1 (C-H aldehyde) and 1496.87cm -1 (Ar-COH for ring C=C).
INTRODUCTION: Aspirin is widely used as an analgesic or pain reliever and for reducing fever. It is also helps to prevent the heart attacks, strokes and blood clot formation in people at risk of developing blood clots. Aspirin is also known as acetylsalicylic acid is an aromatic compound that contains both a carboxylic acid functional group and an ester functional group. Aspirin is a weak monoprotic acid that only slightly soluble in water and acidic solution. It can form hydrogen bonds with polar water molecules. Aspirin is more soluble in alkaline solution, so it is readily dissolves in the duodenum which is first part of human intestine. The infrared absorption only occurs when the IR radiation interacts with the molecules that undergo change in dipole moment as it vibrate or rotate and when the incoming IR photon has sufficient energy for the transition to the next allowed vibrational state. Large net dipole moment change will cause stronger intensity of the band in IR spectrum. FTIR is a simultaneous analysis of the full spectra range using interferometry. The main optical components of FTIR spectrometer are, source, interferometer, beamsplitter, laser and detector. The sample can be in solid, liquid or gas. There are two types of sample handling
techniques for solid sample that are by pellet or mull. For this experiment, the pellet sample handling was used. OBJECTIVES: 1. To perform KBr-handpress method. 2. To obtain IR spectra of penachetin, caffeine, acetylsalysilic acid (ASA), aspirin and an unknown.
EXPERIMENTAL: 1. Preparation of pellet: a. Solid penachetin was mixed with KBr solid in the ratio of 1:99 in the pestle. b. The mixture was grinded until the shiny solid appear. c. The mixture then was inserted into the handpress die to form the pellet. d. The pellet was taken for analysis. e. Other pellets were done by same procedure for caffeine, ASA, aspirin and the unknown. RESULT: a. IR band assignments of acetylsalicylic acid (aspirin) Bonds Name C=O C-O C=C O-H C-O
Notes Carboxylic acid Carboxylic acid Aromatic ring Carboxylic acid Carboxylic acid
Wavenumber (cm-1) Theoretical Experimental 1780-1710 1754.6 1300-1000 1188.26 1600-1580 1606.1 3300-2500 (broad) 2872.63 1320-1210 1306.67
b. IR band assignments of caffeine Bonds Name C-N C-O
Notes Amine, aromatic amides
Wavenumber (cm-1) Theoretical Experimental 1360-1250 1359.92 1680-1630 1660.47
c. IR band assignments of penachetin Bonds Name
Notes
Wavenumber (cm-1) Theoretical Experimental
N-H C=O C-O
2˚ amide Amide Ether
About 3300 1680-1630 1300-1000
3286.72 1659.47 1245.61
d. IR band assignments of unknown A (C7H6O2-salicylaldehyde) Bonds Name C-H Ar-COH
Notes Aldehyde Aldehyde (for ring
Wavenumber (cm-1) Theoretical Experimental 2860-2800 (weak) 2834.15 1600-1450 1496.87
C=C)
DISCUSSION: Acetylsalicylic acid is also known with the name of aspirin, so that the spectrum between ASA standard and aspirin is mostly the same. Any subtle different may be due to the solid that may contaminate by impurities from other sources. The functional group of ASA is the carboxylic acid, so that the signals are based on the IR absorption of carboxylic acid functional group. Caffeine contains two functional groups that are amine and amide, so that it shows a signal for both functional groups. Same goes to penachetin that has functional group of amide and ester. Penachetin shows 2 weak signals for amide functional group at 3286.72cm -1 and 1659.47cm-1, and a sharp and strong signal for C-O ether at 1245.61cm -1. The IR band for salicylaldehyde (unknown A) shows the broad aldehyde functional group signal at 2834.15cm-1 for C-H aldehyde and at 1496.87cm -1 weakly for Ar-COH aldehyde for ring C=C. Aspirin sample should have the same spectrum as the standard ASA because it contains same molecular structure and of course the same functional group. Any different between the spectrums may due to the interferences from environment or contamination of the sample. It is necessary to run the background spectrum before starts with analysing other compounds. This is because the background spectrum contains the water molecules in the air moisture and also the carbon dioxide in the environment of the analysing, so that when the compounds spectra are analysed, the water and CO 2 will be deducted to get only the signal for the particular compound. The FTIR instrument uses the laser as the internal calibrator, so that there is no need to do the calibration
by using the standard polystyrene in order to know the efficiency of the instrument like in the dispersive IR instrument.
CONCLUSION: The spectrums for all standards, sample aspirin and the unknown A were obtained by running the FTIR and the unknown A is proven to be the salicylaldehyde with the respective bonds observed in the spectrum.
REFERENCES: 1. Aspirin (acetylsalicylic acid), Retrieved April 22, from http://www.ausetute.com.au/aspirin.html 2. F. J. Holler, D. A. Skoog, S. R. Crouch (2007), Principles of Instrumental Analysis 6th ed.), United States, Brooks/Cole Cengage Learning. 3. A. Chan (2002), Synthesis and Analysis of Acetyl Salicylic Acid, Retrieved April
22,
from
http://www.joshstaiger.org/amychan/Literary/Lab%20Three
%20Report%20Aspirin.pdf 4. V Renganayaki* S Srinivasan and S Suriya, Vibrational Spectroscopy Investigation on Aspirin Using Semi-Empirical Calculations, Retrieved April 22, from http://sphinxsai.com/2012/july_sept12/Chem/pdfchem/CT=23%28983990%29%20JS%2012.pdf