# Determination of aspirin and caffeine Essay

### Consequences:

Identify and tag the signals in the spectra and note the chemical displacement values of the methyl resonances in acetylsalicylic acid and caffeine and the methylene resonance in s-trioxane.

Using above look, calculate the weight of acetylsalicylic acid and caffeine in one tablet, and the per centum w/w of each constituent in one analgetic tablet.

We will write a custom essay sample on
Determination of aspirin and caffeine Essay
or any similar topic only for you

Whole tablet weighed = 0.501

Half tablet weighed = 0.270

Mass of s-trioxane = 0.05

RMM of aspirin = 180

RMM of caffeine = 194

RMM of s-trioxane = 90

No. of moles of constituents = component integral/no. of protons giving signal

No. of moles of standard criterion integral/ no. of protons giving signal

To happen out the weight and per centum w/w of Aspirin and Caffience following computations were made:

### Aspirin:

No of moles of constituents ( ten ) = ?

No of moles of standard = mass of s-trioxane / RMM of s-trioxane

= 0.05 / 90 = 0.000555

Component built-in = 202.72

No of protons giving signal = 3

Standard built-in = 200

No of protons giving signal = 6

Puting values in the above eq.1:

ten / 0.000555 = ( 202.72/3 ) / ( 200/6 )

x/0.000555 = 67.57 / 33.33

ten = 67.57 x 0.000555 / 33.33

ten = 0.00113 moles

Mass of aspirin = moles x RMM

= 0.00113 ten 180 = 0.203g = 203mg

% w/w of acetylsalicylic acid in the tablet = mass of aspirin / mass of the tablet x 100

= 0.203 / 0.501 x 100

= 40.5 %

### Caffeine:

No of moles of constituents ( ten ) = ?

No of moles of standard = mass of s-trioxane / RMM of s-trioxane

= 0.05 / 90 = 0.000555

Component built-in = 14.0

No of protons giving signal = 3

Standard built-in = 200

No of protons giving signal = 6

Puting values in the above eq.1:

ten / 0.000555 = ( 14.0/3 ) / ( 200/6 )

x/0.000555 = 4.66 / 33.33

ten = 4.66 x 0.000555 / 33.33

ten = 0.0000775 moles

Mass of caffeine = moles x RMM

= 0.000075 ten 194 = 0.0145g = 14.5 milligram

% w/w of acetylsalicylic acid in the tablet = mass of aspirin / mass of the tablet x 100

= 0.0145 / 0.501 x 100

= 2.89 %

### Discussion:

1. Remark on the chemical displacement places of the methyl groups in acetylsalicylic acid and caffeine.
2. Aspirin shows about 6 vests in the spectrum, all in different environment. It has got one methyl group which gives rise to a vest at? 2.3498 as there are no neighbors and the n+1 regulation is followed. It has built-in of 3 as three protons are giving rise to the chemical displacement at? 2.3498. The four vests between? 7.1292 – ? 8.1123 correspond to benzene ring protons. In acetylsalicylic acid there is a really wide vest at? 11.0082 due to the carbonyl next to hydroxyl proton which shifts it towards the left manus side.

Caffeine has got three methyl groups which give rise to three vests as all the three methyl groups are in different environments to each other. All the three extremums have built-in of 3 which arises due to the three protons on each methyl groups. The first vest at? 3.4133 is due to the protons ( a ) following to nitrogen with individual bond. The 2nd vest is seen at? 3.5910 matching to protons ( degree Celsius ) next to duplicate bonded C and O and the last methyl vest ( B ) at? 4.004 is due to the protons next to two two-base hit bonded Os attached to two Cs. There is besides a vest seen at? 7.5172 that arises due to a individual proton CH between two Ns.

3. Compare your consequences to the contents claimed by the maker and discourse any differences observed.
4. How does this method comparison with findings by UV optical density and HPLC. What are the NMR method ‘s restrictions?
5. UV techniques are simple and rapid. It can be used for the quantitative finding of extremely conjugated compounds and metal ions. Metallic ions can be coloured and determined by UV. HPLC is a separation techniques used for compounds on footing of their rate of elution and can divide complex mixtures. HPLC analysis is really speedy with high declaration. The stationary column can be used repeatedly for figure of times. In HPLC analysis, automated instrumentality and quantitation can be used. It besides has low sensitiveness and truth. NMR is an expensive technique. Compared to UV and HPLC the instrumentality is more dearly-won. The sample to be analyzed has to be free of any contaminations. It takes longer clip as compared to the other techniques mentioned. In NMR the chemical displacement corresponds to the construction of the molecule being analysed so for compounds with similar constructions it is hard to divide the signals. Besides it is an insensitive technique.

### Mentions:

• hypertext transfer protocol: //www.pg.gda.pl/chem/CEEAM/Dokumenty/Warsztaty/Levsen.pdf