samplepreparation

Sample preparation is the set of processes that convert a raw material into a form suitable for analytical measurement. It is used across disciplines such as analytical chemistry, biology, materials science, geology, and forensics. The aim is to produce a representative, stable sample that minimizes bias and matrix effects while preserving the target analytes and removing substances that could interfere with measurement.

A typical workflow includes receiving and storing the material, defining a sampling strategy, homogenizing or subdividing the sample, pretreatment or digestion, extraction or dissolution, cleanup or purification, and concentration or dilution prior to analysis. For solids, milling or grinding and sieving are common; for liquids, degassing or phase separation may be needed; for biological materials, homogenization followed by chemical or enzymatic lysis is typical. Digestion with acids or solvents is often used to release analytes for instrumentation such as ICP-MS or AAS, and cleanup steps such as filtration or solid-phase extraction reduce matrix effects. Samples should be analyzed promptly or preserved to maintain stability.

Key considerations include representativeness, prevention of cross-contamination, maintenance of analyte stability, and avoidance of loss of volatile components. Documentation of handling, storage conditions, and transport is important for traceability and reproducibility. Quality control relies on blanks, calibration standards, internal standards, certified reference materials, and replicate analyses, aligned with regulatory frameworks such as Good Laboratory Practice and ISO 17025 when applicable.