Exploration of the specific shift value of paracetamol in ethyl acetate
The origin of the experiment
To clarify the Rf value of paracetamol in the environment of ethyl acetate, this value is of great significance in many fields such as material qualitative analysis, so this investigation is carried out.

Experimental preparation
1. ** Material preparation **: Select pure paracetamol products to ensure that their purity meets the experimental standards; prepare an appropriate amount of ethyl acetate to ensure its good quality. At the same time, prepare the necessary materials for experiments such as silicone plates, and the silicone plates should be clean, flat and flawless.
2. ** Instrument preparation **: Take the high-performance liquid chromatograph, and fully calibrate and debug it before use to ensure that the performance indicators of the instrument are in the best condition to ensure the accuracy and reliability of the experimental data. Another sampling device, unfolding cylinder and other instruments are prepared to ensure cleanliness and intact function.

Operation implementation
1. ** Spotting operation **: Use an accurate sampling device, dip an appropriate amount of acetaminophen solution, and carefully sample at the starting position of the silicone plate. The spotting spots should be small and uniform, with a diameter of 2-3 mm. The sampling process should be rapid and accurate to avoid sample diffusion or staining.
2. ** Deployment link **: Place the sampled silica gel plate smoothly in the deployment cylinder pre-filled with ethyl acetate development agent. The expansion cylinder should be well sealed to prevent the development agent from evaporating. Make sure that the depth of the development agent is properly immersed in the sampling end of the silica gel plate, about 0.5-1 cm, and the sample spots should not be directly in contact with the level of the development agent. When the development agent rises evenly along the silica gel plate, to a predetermined height, quickly remove the silica gel plate and mark the leading edge of the development agent.

Result judgment
1. ** Measurement calculation **: After the silica gel plate is dried, acetaminophen spots can be clearly seen when observed under a specific wavelength ultraviolet lamp. Accurately measure the distance from the center of the spot to the origin and the distance from the front of the developing agent to the origin with a ruler. According to the calculation formula of Rf value: Rf = the distance from the center of the spot to the origin/the distance from the front of the developing agent to the origin, carefully calculate the Rf value of paracetamol in ethyl acetate.
2. ** Analysis and discussion **: Compare the Rf value obtained this time with the relevant literature or similar experimental data in the past. If the numerical deviation is large, it is necessary to carefully investigate all aspects of the experimental process, such as the difference in the amount of sample, the purity and proportion of the developing agent, and the change of the temperature and humidity of the developing environment, to investigate the cause of the deviation, so as to continuously optimize the experiment and improve the reliability and accuracy of the results.