The Degradation of Acetaminophen in Water using Bleach

Acetaminophen is a very common antipyretic, mainly found in Tylenol. Because of climate change, there will be a time when climate change related weather events such as heavy rainfall, will cause the destruction of water supply infrastructure, lower the water resource availability, and reduce the quality of consumable water. As of 2020, only 30% of rural populations in the poorest countries have water that is clean of fecal and priority chemical contaminants, showing how important the removal of acetaminophen from water is. The main way acetaminophen gets into ground water is though excretion after consumption, and when flushing unwanted medication that contains acetaminophen. Up to 9% of initial acetaminophen is excreted after being metabolized through the body. The use of a bleach tablet in the toilet bowl will degrade the acetaminophen before being flushed. Even small concentrations of acetaminophen influence fish populations including disturbing normal development of the embryos. Solutions of 5 and 10 ppm acetaminophen were made to convey the concentration of acetaminophen that may be found in the environment. Both were inserted into a UV-Vis spectrophotometer. The λmax was found to be 242.5 nm for both solutions which was needed for the UV detector on the HPLC. The 10 ppm acetaminophen and water solution was run in the HPLC. A good mobile phase is important for the resolution and separation of peaks of the chromatogram. The solvent composition was 94.5:5.5 water:acetonitrile solution, which produced a sharp peak at 3.5 minutes. All trials had a flow rate of 1.5 mL/min and ran for 10 minutes. After seeing inconsistency in retention times, the solvent was improved to take 0.4% of the HPLC grade water, to make room for 0.2% triethylamine and 0.2% acetic acid. All solvents (water, acetonitrile, triethylamine and acetic acid) were combined into the same container to improve the difference in viscosity between water and acetonitrile, which was adding pulses in the chromatograms at a consistent time (every 0.5 minutes). A rerun of all samples (1, 2, 3, 4. 5 and 10 ppm) with all siphons in the one solvent, were done to find a peak at about 6.5 minutes. From this data, a calibration curve was made based on concentration of acetaminophen. The line of best fit equation is y=495327x+570950 with an R2 value of 0.8732. Preliminary kinetic experiments measuring the effect of bleach an acetaminophen degradation are ongoing.