LiChrolut^® Solid Phase Extraction Columns

Section Overview:

• Introduction
• LiChrolut^® Sorbents & Columns
• Extraction Cartridge Selection Guide
• Steps of Solid Phase Extraction

Introduction

Extraction is a vital step in sample preparation before chromatographic analysis. It has been shown to enhance analyte concentration by a factor of 100 to 5,000, thereby significantly improving detection sensitivity. As part of selective and specific sample preparation, extraction ensures a more reliable and cost-effective chromatographic analysis. Offline and online extraction are two different approaches used in sample preparation. Offline extraction involves manual processing before transferring samples to an analytical instrument, while online extraction automates the process within the system itself.

We offer a range of high-quality products for offline as well as online extraction. For offline methods, the range includes EXtrelut^® sorbents and columns for liquid-liquid extraction, as well as LiChrolut^® sorbents and columns for solid-phase extraction.

LiChrolut^® solid phase extraction tubes are specifically designed for reliable and rapid solid-phase extraction, using the principles of liquid chromatography. They achieve this through strong yet reversible interactions between the analyte and the stationary phase surface. Common interactions include hydrophobic forces (Van der Waals), polar forces (hydrogen bonding, dipole-dipole), or ion exchange mechanisms. These columns also offer a range of surface modifications to meet different extraction needs, including non-polar extraction (LiChrolut^® RP-18 and RP-18 endcapped), polar extraction (LiChrolut^® CN), cation exchange extraction (LiChrolut^® SCX), mixed-mode extraction (LiChrolut^® TSC).

These columns ensure outstanding consistency between batches by rigorously testing raw materials and thorough quality control on the finished product. Their production process is optimized, validated, and certified, to ensure high levels of purity and uniformity. The multi-stage purification techniques used with LiChrolut^® materials are particularly beneficial for trace analysis since they lower the proportion of elutable components, resulting in purer extracts. Furthermore, all stationary phases are monitored using highly sensitive analytical methods, ensuring their adherence to extremely narrow tolerance limits.

Features & Benefits

• Rapid sample preparation within minutes
• Higher recoveries without emulsion formation
• Highly precise analytical results using disposable cartridges
• Reduced solvent usage, allowing for lower material and disposal costs
• Possibility of automating the entire process

LiChrolut^® Solid Phase Extraction Cartridge Selection Guide

The ideal extraction method is determined by the structure, solubility, polarity, and lipophilic characteristics (distribution coefficients) of an analyte. Table 1 will help you choose the most suitable LiChrolut^® column for your specific application.

4 Steps of Solid Phase Extraction with LiChrolut^® Extraction Unit

The LiChrolut^® extraction unit (1.19852) provides an efficient and a reliable solution for every step of solid-phase extraction. This transparent, vacuum-compatible glass unit can process up to 12 samples at the same time, delivering high throughput and consistent results. To ensure optimal analyte recovery, it is essential to carefully optimize each of the steps of the solid-phase extraction process.

1. Conditioning of the Sorbent: It is essential to solvate the chemically modified silica gels with an organic solvent, such as acetonitrile or methanol, before conditioning them. This conditioning involves preparing the gels for the sample milieu with water or buffer solution to ensure their accessibility for the analyte. It is essential to achieve reproducible sorption of the analyte. Any excess organic solvent can be removed using water or a buffer solution.
2. Application of the Sample: It involves using pressure or vacuum to introduce the sample solution into the conditioned extraction cartridges. The analyte concentrates in a narrow zone on the sorbent during this step, and it is ideal for the matrix components to neither flow through the cartridge nor be adsorbed onto it.
3. Washing: Using a small volume of water or buffer, further interfering matrix components are removed from the stationary phase's surface. A water-buffer solution with only a small quantity of methanol can also be used.
4. Elution of Adsorbed Analytes: In the last step of solid-phase extraction, the analyte is desorbed using an appropriate solvent and subsequently eluted. Following the concentration or dilution of the eluate, analysis can proceed without any delay. It is essential to choose a solvent that diminishes the interaction between the analyte and the sorbent, while also promoting an even distribution of the analyte within the eluent. The selection of a solvent must rely on a thorough understanding of the analyte’s structure, solubility, polarity, and lipophilic characteristics (distribution coefficients).

Advantages of LiChrolut^® Solid Phase Extraction Unit

• A front-positioned manometer regulates the vacuum, ensuring precise control throughout the operation.
• The glass vessel, lid, and accessories are made from inert and easy-to-clean materials, eliminating the risk of residue contamination in subsequent extractions.
• Standard accessories accommodate a wide range of collecting vessel sizes, from volumetric flasks to auto-sampler vials, offering flexibility in sample collection.