In the actual testing process, the sample matrix may be different from the standard solution, so the sample needs to be digested, extracted and other pre-treatment before the content determination. If the sample pretreatment is incomplete, the removal of interfering substances in the matrix is insufficient, or the loss of the target substances during the pretreatment process, it may lead to inaccurate results (in this case, you can usually choose a matrix similar to that of the proficiency testing sample to perform the spiked recovery test at the same time).
Sample pretreatment is categorized into organic and inorganic treatments.
Inorganic pre-treatment equipment: oven, acid vat, (dry and wet samples) mills, temperature-controlled shaker, ultrasonic cleaner, bench-top centrifuge, electric heating plate, microwave digestion instrument and so on.
Organic pre-treatment equipment: ultrasonator, shaker, (fast solvent, fast Soxhlet, microwave) extractor, solid phase extractor, (automatic or semi-automatic, with or without concentration and volume) gel permeation chromatography GPC, rotary evaporator, nitrogen blowing concentrator and so on.