Ethyl acetate extraction procedures
1. Preparations
1. ** Instrument preparation **: Prepare glass instruments such as separation funnels, conical bottles, measuring cylinders, glass rods, etc., to ensure that they are clean and not damaged. Apply an appropriate amount of Vaseline to the separation funnel piston to ensure good sealing, and perform leak detection operations.
2. ** Reagent preparation **: Prepare a sufficient amount of ethyl acetate with purity meeting the experimental requirements, as well as the sample solution to be extracted, and at the same time prepare an appropriate amount of distilled water or other related washing liquid.

2. Extraction operation
1. ** Transfer solution **: Accurately measure a certain volume of the sample solution to be extracted with a measuring cylinder, and carefully pour it into the separation funnel. Subsequently, according to a certain proportion, measure ethyl acetate with a measuring cylinder and slowly add it to the separation funnel. Under normal circumstances, the volume ratio of ethyl acetate to the sample solution can be selected between 1:1 and 1:5 depending on the nature of the sample and the purpose of the experiment.
2. ** Oscillation Mixing **: Plug the upper glass plug of the separation funnel tightly to ensure a good seal. Press the upper glass plug of the separation funnel with your right hand, hold the piston part with your left hand, turn the separation funnel upside down, and start to oscillate slowly. During the oscillation process, unscrew the piston from time to time to deflate to prevent the liquid from being ejected due to excessive internal pressure. The oscillation frequency is maintained at about 30-40 times per minute, and the oscillation is continued for 3-5 minutes to make the ethyl acetate fully contact with the sample solution and realize the transfer of solute.
3. ** Static stratification **: After the oscillation is completed, the liquid separation funnel is placed on the iron ring of the iron frame and left to stand. The standing time depends on the complexity of the solution system. Generally, it takes 10-20 minutes until the solution is clearly stratified. The upper layer is the ethyl acetate phase (usually, if the solute has a large solubility in ethyl acetate, the target substance is mainly enriched in this phase), and the lower layer is the aqueous phase (or other primary solvent phase).

III. Separation and collection
1. ** Separate the lower liquid **: After the solution is completely stratified, carefully open the separation funnel piston, so that the lower liquid slowly flows into the conical bottle below. Control the flow rate to avoid the mixing of the two phases due to the rapid flow rate. When the lower liquid is close to the end, close the piston and try to transfer all the lower liquid to the conical bottle, and do not allow the upper ethyl acetate phase to flow in.
2. ** Collect the upper ethyl acetate phase **: Open the upper glass plug of the separation funnel, and carefully pour the upper ethyl acetate phase into another clean conical bottle. This is the ethyl acetate solution containing the target extract.

IV. Follow-up treatment
1. ** Washing **: If further purification of the extract is required, an appropriate amount of distilled water or other washing liquid can be added to the collected ethyl acetate phase, and the above operation of shaking, standing, and separation can be repeated 1-2 times to remove possible residual impurities.
2. ** Concentration **: Transfer the washed ethyl acetate solution to a distillation device or a rotary evaporator, and under appropriate temperature and pressure conditions, volatilize the ethyl acetate to obtain a concentrated target extract. Collect and properly store the target extract for subsequent analysis and detection.