Determination of aspirin and caffeine

Determination of acetylsalicylic acid and caffeineResultsIdentify and mark the portends in the spectra and note the chemical substance shift value of the methyl resonances in aspirin and caffeine and the methylene resonance in s-trioxane.Using above expression, calculate the weight of aspirin and caffeine in one(a) tablet, and the percentage w/w of each component in one analgesic tablet.Whole tablet weighed = 0.501Half tablet weighed = 0.270Mass of s-trioxane = 0.05RMM of aspirin = clxxxRMM of caffeine = 194RMM of s-trioxane = 90No. of moles of components = component integral/no. of protons giving signalNo. of moles of standard standard integral/ no. of protons giving signalTo find out the weight and percentage w/w of Aspirin and Caffience following calculations were madeAspirinNo of moles of components (x) = ?No of moles of standard = plentifulness of s-trioxane / RMM of s-trioxane= 0.05 / 90 = 0.000555Component integral = 202.72No of protons giving signal = 3Standard integral = 200No of protons giving signal = 6 place set in the above eq.1x / 0.000555 = (202.72/3) / (200/6)x/0.000555 = 67.57 / 33.33x = 67.57 x 0.000555 / 33.33x = 0.00113 molesMass of aspirin = moles x RMM= 0.00113 x 180 = 0.203g = 203mg% w/w of aspirin in the tablet = mass of aspirin / mass of the tablet x 100= 0.203 / 0.501 x 100= 40.5%CaffeineNo of moles of components (x) = ?No of moles of standard = mass of s-trioxane / RMM of s-trioxane= 0.05 / 90 = 0.000555Component integral = 14.0No of protons giving signal = 3Standard integral = 200No of protons giving signal = 6Putting values in the above eq.1x / 0.000555 = (14.0/3) / (200/6)x/0.000555 = 4.66 / 33.33x = 4.66 x 0.000555 / 33.33x = 0.0000775 molesMass of caffeine = moles x RMM= 0.000075 x 194 = 0.0145g = 14.5 mg% w/w of aspirin in the tablet = mass of aspirin / mass of the tablet x 100= 0.0145 / 0.501 x 100= 2.89%DiscussionComment on the chemical shift positions of the methyl groups in aspirin and caffeine.Aspirin shows about 6 si nglets in the spectrum, all in different environment. It has got one methyl group which gives fig out to a singlet at ? 2.3498 as there argon no neighbours and the n+1 rule is followed. It has integral of 3 as leash protons are giving rise to the chemical shift at ? 2.3498. The four singlets between ? 7.1292 ? 8.1123 correspond to benzene ring protons. In aspirin there is a very(prenominal) broad singlet at ? 11.0082 due to the carbonyl adjacent to hydroxyl proton which shifts it towards the left hand side.Caffeine has got tierce methyl groups which give rise to three singlets as all the three methyl groups are in different environments to each other. All the three peaks have integral of 3 which arises due to the three protons on each methyl groups. The first singlet at ? 3.4133 is due to the protons (a) next to nitrogen with single bond. The second singlet is seen at ? 3.5910 corresponding to protons(c) next to double bonded carbon and oxygen and the last methyl singlet (b) a t ? 4.004 is due to the protons next to two double bonded oxygens attached to two carbons. There is in any case a singlet seen at ? 7.5172 that arises due to a single proton CH between two nitrogens.Compare your results to the contents claimed by the manufacturer and discuss any differences observed.How does this rule compare with determinations by UV absorbance and HPLC. What are the NMR methods limitations?UV techniques are simple and rapid. It can be used for the quantitative determination of highly commingle compounds and metal ions. Metal ions can be coloured and determined by UV. HPLC is a separation techniques used for compounds on basis of their rate of elution and can break out complex mixtures. HPLC analysis is very quick with high resolution. The stationary column can be used repeatedly for number of times. In HPLC analysis, automated instrumentation and quantitation can be used. It also has low sensitivity and accuracy. NMR is an expensive technique. Compared to UV a nd HPLC the instrumentation is more costly. The sample to be analyzed has to be rationalize of any contaminants. It takes longer time as compared to the other techniques mentioned. In NMR the chemical shift corresponds to the structure of the molecule being analysed so for compounds with similar structures it is punishing to separate the signals. Also it is an insensitive technique.Referenceshttp//www.pg.gda.pl/chem/CEEAM/Dokumenty/Warsztaty/Levsen.pdfhttp//wiki.answers.com/Q/Advantages_and_disadvantages_of_HPLChttp//www.answers.com/topic/hplc-high-performance-liquid-chromatographyhttp//www-unix.oit.umass.edu/mcclemen/581Proteins.htmlhttp//wapedia.mobi/en/Ultraviolet-visible_spectroscopyhttp//books.google.co.uk/books?id=Dvoeg3erhRECpg=PA297lpg=PA297dq=limitations+of+nmr+spectroscopysource=blots=ea8zhh6QdCsig=v3mtaKE11Git3TMIX06mK3KD3yIhl=enei=BStBS5abEJj20wTkg6mSBQsa=Xoi=book_resultct=resultresnum=6ved=0CBoQ6AEwBTgKv=onepageq=limitations%20of%20nmr%20spectroscopyf=false