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HIGH SCHOOL

Chemistry

Concept Videos

Analytical Chemistry

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Method Development and Sampling Techniques

Preparing Samples by State and Form

Description

Sample preparation depends on the state and form of the sample before analysis. It helps make the sample ready for accurate measurement. The main goal is to extract the analyte, which is the substance being measured, and remove parts that could interfere with the analysis.

Solid samples often nee...

Transcript

样品制备是获得准确分析结果的关键步骤,主要包括三个目标:提取、纯化和浓缩。

首先,提取过程涉及从样品基质中分离出含有目标分析物的混合物。其次,如果存在干扰物质,则将其去除以获得纯净的样品。第三,如果提取的分析物浓度较低,则需将其浓缩至能够被准确检测的水平。

样品的常见形态包括固体、液体和气体。过大的固体块状物无法直接分析,需通过研磨、压碎和铣削等物理方法粉碎成粉末。

将此混合物过筛并混合,得到均匀的细粉,然后将其干燥并溶解于合适的溶剂中,以将分析物提取到溶液中。

与固体不同,液体悬浮液在分析前需经过过滤或离心处理,以去除不纯的固体颗粒。

由于固体吸附剂可选择性地吸附气态分析物,因此气体样品无需进行前处理。