solid phase extraction
Solid phase extraction (SPE) is a sample-preparation technique developed in the mid-1970s
from classical chromatography. It concentrates and purifies analytes by selective adsorption
onto a solid sorbent, followed by elution with a minimal volume of solvent.
1. Fundamental Principles
Solid phase extraction brings an aqueous or organic sample into contact with a solid sorbent
packed in a cartridge, disk, or tip. By selecting sorbents with specific functional groups, target
compounds bind preferentially, while matrix interferences are washed away. Subsequently,
analytes are eluted using a solvent that disrupts their affinity for the sorbent.
2. Detailed SPE Workflow
Sample Pre-treatment → Conditioning → Loading → Washing → Elution → Post-
Processing
Sample Pre-treatment
Before beginning the analytical procedure, it is crucial to carefully adjust the sample's pH or
ionic strength. This step significantly enhances the charge or partition behavior of the analytes
present in the sample, thereby improving their interaction with the subsequent sorbent material.
By optimizing these parameters, the efficiency of analyte extraction can be markedly increased,
leading to more reliable results in the analysis.
Conditioning
Once the sample has been pre-treated, the next step is to condition the sorbent. This involves
flushing the sorbent cartridges or columns with an appropriate organic solvent, such as
methanol. The purpose of this step is to thoroughly wet the pores of the sorbent material,
ensuring that it is fully activated and ready for optimal analyte binding. After the initial
conditioning with the organic solvent, it is essential to equilibrate the system with an aqueous
buffer that matches the sample matrix. This approach helps to establish a stable environment
conducive to the effective retention of the target analytes.
Loading
Solid phase extraction (SPE) is a sample-preparation technique developed in the mid-1970s
from classical chromatography. It concentrates and purifies analytes by selective adsorption
onto a solid sorbent, followed by elution with a minimal volume of solvent.
1. Fundamental Principles
Solid phase extraction brings an aqueous or organic sample into contact with a solid sorbent
packed in a cartridge, disk, or tip. By selecting sorbents with specific functional groups, target
compounds bind preferentially, while matrix interferences are washed away. Subsequently,
analytes are eluted using a solvent that disrupts their affinity for the sorbent.
2. Detailed SPE Workflow
Sample Pre-treatment → Conditioning → Loading → Washing → Elution → Post-
Processing
Sample Pre-treatment
Before beginning the analytical procedure, it is crucial to carefully adjust the sample's pH or
ionic strength. This step significantly enhances the charge or partition behavior of the analytes
present in the sample, thereby improving their interaction with the subsequent sorbent material.
By optimizing these parameters, the efficiency of analyte extraction can be markedly increased,
leading to more reliable results in the analysis.
Conditioning
Once the sample has been pre-treated, the next step is to condition the sorbent. This involves
flushing the sorbent cartridges or columns with an appropriate organic solvent, such as
methanol. The purpose of this step is to thoroughly wet the pores of the sorbent material,
ensuring that it is fully activated and ready for optimal analyte binding. After the initial
conditioning with the organic solvent, it is essential to equilibrate the system with an aqueous
buffer that matches the sample matrix. This approach helps to establish a stable environment
conducive to the effective retention of the target analytes.
Loading
