Task: Question Answering
Input (English): Question: In some sample treatments, the solid phase extraction technique is used. Said technique: 
 Options:  <1> It has the advantage that solvents are not required. <2> It is applied by contacting the solid sample with the stationary phase contained in a cartridge. <3> It does not require the application of pressure or vacuum. <4> It allows carrying out the preconcentration of large volume samples. <5> It is characterized by the high consumption of solvents.
Output (English): 4