ANALYSIS OF ASA

Purpose

To perform an investigation to accurately determine the ASA content of an over-the-counter pain reliever and to compare the result with the quantity stated on the product label.

Prediction

Based on the manufacturer's claim on the label of the bottle of ASA, I predict that the experiment will be 325 mg.

Materials

• Eye protection

• 4 125 ml flasks

• 4 samples of potassium hydrogen phthalate (KHP)

• distilled water

• phenolphthalein

• NaOH(s)

• 500 ml volumetric

• buret

• buret clamp

• stirring rod

• ring stand

• mortar

• pestle

• ASA tablets

Procedure

Observations

Table 1: Standardizing

Average concentration = .14509

The percentage difference of the actual concentration of NaOH and the desired concentration is:

Table 2:

Average concentration = .59005

Conclusions

• Use stoichiometric calculations to determine the mass of ASA in a tablet.

• Evaluation

• Evaluate the evidence gathered by evaluating the Experimental Design, the materials, the procedure, and the skills of experimenters. Indicate sources of error and suggest ways to improve the investigation.

Sources of error/uncertainties:

• When the tablet is squashed into powder some of it stays in the paper or the powder may also stick to the walls of the beaker when poured.

• NaOH is a base which can vary the results because it is hydroscopic, not using a hydroscopic base would make the results more accurate.

• When the base was being standardized, the results could have been more consistent by using more effectively the pipet.

• When KHP and NaOH were being weighed, the results were not always as desired.

• When the meniscus in the pipet was being read the experimenter could have analysed it incorrectly. Making the results to slightly vary.

Options to improve the experiment

• Use a standardized base. Therefore there would be less sources of error.

• Instead of first weighing the tablet and then squash it. The experimenter should weigh the beaker before pouring in the powder and then weigh it after it has being poured, avoiding the source of error when leaving some powder in the paper or outside the beaker.

• Calculate the percentage difference between the predicted and experimental mass.

The percentage difference between the predicted mass and experimental mass is .31%

• Evaluate the Prediction and the manufacturer's claim.

My prediction was based on the manufacturer's claim and the mass predicted that would be obtained was really accurate. In a common ASA tablet the manufacturer claims that it contains 75% of the “active ingredients” which on this experiment it was discovered to be true. Any discrepancy in the results was based on uncertainties.

• Synthesis

• Why are some ASA tablets coated or buffered?

Buffered ASA tablets are made because a small percentage of individuals may occasionally experience stomach upset with ASA. Buffered ASA products neutralize stomach acid by raising the PH.

There are two types of coated ASA tablets:

• Micro-coating refers to the film coating on the ASPIRIN tablet and caplet. This very thin coating makes the tablet easier to swallow for those who have difficulty swallowing uncoated tablets and caplets.

• Enteric coating is a delayed-release safety coating. It is designed to allow the ASPIRIN tablet or caplet to pass through the stomach to the small intestine (duodenum) before dissolving.

Products with enteric coating are not recommended for quick pain relief; enteric-coated ASPIRIN is most often used by patients who are taking ASPIRIN on a daily basis under their doctor's supervision or recommendation.

• What other ingredients are included in medication tablets, and why?

I could not find the exact ingredients that are included but they are included to counteract the acid in the tablet for people who experience problems with the acid in their stomachs because it is too strong or any type of problem. That is why some aspirins are buffered and some are coated.

The quantity of “active ingredient” in a commercial ASA tablet is 75.34% and the rest of the tablet (24.66%) are just “inert” ingredients.

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