Identification Of Acetaminophen
Objectives
This experiment aims to analyse the given sample of acetaminophen, Sample A, to see if it complies with the monograph in the British Pharmacopoeia (BP) for the identification of acetaminophen, the limit test for p-aminophenol and the assay for acetaminophen. Procedure Identification for Acetaminophen
Potassium bromide (KBr) disc technique was used to prepare the sample for the infrared absorption spectrophotometry. The agate mortar and pestle were cleaned with absolute ethanol using lint free paper. 5 micro-spatula of KBr and 1 micro-spatula of Sample A were mixed together in the mortar. A pellet was dropped with the shiny side faced up into the evacuable die. Then using the flat end of the micro-spatula, a very thin layer …show more content…
Then, 5.0 mL of ethanol and 5.0 mL of water were added slowing to dissolve the solid sample using a measuring cylinder. With a micropipette, 0.1 mL (100 µL) of 10 g/L sodium nitroprusside and 0.1 mL (100 µL) of anhydrous sodium carbonate were added to the solution. The solution was then mixed and allowed to stand for 30 minutes. After that, a 50 ppm standard was prepared using the same manner, replacing the 0.50 g of sample with 0.5 g of 4-aminophenol-free paracetamol. 0.5 mL of 0.05 g/L solution of 4-aminophenol was added using a plastic dropper as well. For the sample to comply with the monograph in the British Pharmacopoeia (BP), the intensity of the blue colour formed in the test solution should not be higher than that of the …show more content…
Discussion Identification for Acetaminophen
Infrared spectrophotometry, which is an ideal tool for determination of organic and inorganic compounds, was used to test for the identity of Sample A in this experiment.
KBr disc technique was used to prepare the sample. According to the Beer-Lambert Law, a lower concentration of sample is required since the disc film is much thicker than a liquid film. If the concentration is too high, a clear disc film may not be obtained, causing the IR beam to be absorbed completely or scattered from the sample which results in very noisy spectra.
The mixing of the KBr powder and Sample A should be done quickly as the finely powdered potassium bromide will absorb more humidity from the air due to its hydroscopic property, leading to an increased background in certain ranges. The table below is a list of functional groups in acetaminophen, the types of bonding and their respective theoretical wave numbers.
Functional group Type of bonding Wave number/cm-1
Aromatic Aromatic overtone region 1840 –
This experiment aims to analyse the given sample of acetaminophen, Sample A, to see if it complies with the monograph in the British Pharmacopoeia (BP) for the identification of acetaminophen, the limit test for p-aminophenol and the assay for acetaminophen. Procedure Identification for Acetaminophen
Potassium bromide (KBr) disc technique was used to prepare the sample for the infrared absorption spectrophotometry. The agate mortar and pestle were cleaned with absolute ethanol using lint free paper. 5 micro-spatula of KBr and 1 micro-spatula of Sample A were mixed together in the mortar. A pellet was dropped with the shiny side faced up into the evacuable die. Then using the flat end of the micro-spatula, a very thin layer …show more content…
Then, 5.0 mL of ethanol and 5.0 mL of water were added slowing to dissolve the solid sample using a measuring cylinder. With a micropipette, 0.1 mL (100 µL) of 10 g/L sodium nitroprusside and 0.1 mL (100 µL) of anhydrous sodium carbonate were added to the solution. The solution was then mixed and allowed to stand for 30 minutes. After that, a 50 ppm standard was prepared using the same manner, replacing the 0.50 g of sample with 0.5 g of 4-aminophenol-free paracetamol. 0.5 mL of 0.05 g/L solution of 4-aminophenol was added using a plastic dropper as well. For the sample to comply with the monograph in the British Pharmacopoeia (BP), the intensity of the blue colour formed in the test solution should not be higher than that of the …show more content…
Discussion Identification for Acetaminophen
Infrared spectrophotometry, which is an ideal tool for determination of organic and inorganic compounds, was used to test for the identity of Sample A in this experiment.
KBr disc technique was used to prepare the sample. According to the Beer-Lambert Law, a lower concentration of sample is required since the disc film is much thicker than a liquid film. If the concentration is too high, a clear disc film may not be obtained, causing the IR beam to be absorbed completely or scattered from the sample which results in very noisy spectra.
The mixing of the KBr powder and Sample A should be done quickly as the finely powdered potassium bromide will absorb more humidity from the air due to its hydroscopic property, leading to an increased background in certain ranges. The table below is a list of functional groups in acetaminophen, the types of bonding and their respective theoretical wave numbers.
Functional group Type of bonding Wave number/cm-1
Aromatic Aromatic overtone region 1840 –