Selection Proper Models and Introduction of C18 HPLC Column

High performance liquid chromatography is a technique that is widely used to separate, identify, and quantify every component in a sample mixture in analytical chemistry. The principle of HPLC is as following: when the pressurized liquid solvent containing the sample mixture pass through a column filled with a solid adsorbent material by pumps, the different component in the sample will interact with the adsorbent material slightly differently. That will cause different components to flow at different rates and make components separated when they flow out of the column.

Fitting with most HPLC instruments, Hawach provides empty HPLC columns and supplies prepacked ones with the full range of material which can provide a very high matrix-tolerance, make it suitable for the separation of matrix-rich samples perfectly.

With the excellent double end-capping technology, Hawach’s HPLC Columns have high purity bonded phase packed in 100,000 class cleaning rooms. The long Average particle sizes and pore sizes of HPLC Columns ensure the excellent flow rate, and the wide pH range makes the lifetime of the columns long.
High Purity HPLC Columns

Importance of Proper Models of HPLC Column

In practical application, proper models of the HPLC column have a great influence on the performance or operation of the HPLC column. Improper models could greatly reduce the filtration effect. The HPLC column of high purity silica gel matrix is selected for different brands; the HPLC column with a high seal end is selected for alkaline compounds; the HPLC column with special seal end is used for high pH value to ensure column life and improve peak shape.

Selecting Proper Models:

  1. Analyte Properties:
    • Consider the hydrophobicity and polarity of your analytes. C18 columns are best suited for non-polar to moderately polar compounds.
  2. Sample Type:
    • Determine if your samples are aqueous, organic, or a mixture. For samples with higher water content, a column with enhanced aqueous stability may be needed.
  3. Column Dimensions:
    • Choose the appropriate column length and internal diameter based on the expected sample complexity and flow rate requirements.
  4. Particle Size:
    • Smaller particle sizes (e.g., 1.8 µm) provide higher resolution but may require higher backpressure. Larger particle sizes (e.g., 5 µm) are more suitable for routine analyses.
  5. End-Capping:
    • Consider if the column is end-capped. End-capping reduces silanol activity, improving peak shape for basic compounds.
  6. Column Brand and Quality:
    • Select reputable manufacturers known for producing high-quality columns. Factors like batch-to-batch consistency and quality control are crucial.
  7. Specialized C18 Columns:
    • Some manufacturers offer specialized C18 columns, such as columns for ultra-high-pressure liquid chromatography (UHPLC) or columns designed for specific applications (e.g., pharmaceutical analysis).
  8. pH Range:
    • Check the pH stability range of the column, especially if your analysis involves extreme pH conditions.
  9. Budget:
    • Consider your budget constraints, but prioritize column quality to avoid compromising results.

Tips for Selection of Proper Models of HPLC Column

Hawach Scientific lists some useful tips for your selection. Read the HPLC column instructions carefully to understand the parameters and properties of the various HPLC columns; understand the properties of compounds, such as polarity, acidity, and alkalinity, impurity properties, etc.; use AQ column for strongly polar compounds; high surface area and carbon loading can increase the sample size of the prepared chromatography. Moreover, the chromatographic column with the polar group sealing end can be used in the high water phase and is suitable for separating polar compounds.

Details on C18 HPLC Column

C18 HPLC column, abbreviated as “ODS” column, that is, octadecyl bonded silica gel packing. This kind of packing plays a very important role in reversed-phase chromatography, and it can complete the analytical task of 70% 80% high-performance liquid chromatography (HPLC). Because C18 is a long chain alkyl bonded phase with higher carbon content and better hydrophobicity, it has stronger adaptability to various types of biological macromolecules and is the most widely used.

Basic Principles for Selection of C18 HPLC Column

There are some suggestions on the selection of C18 HPLC columns in your application. To prevent the trailing of alkaline compounds by selecting the filler sealed by alkylation; select columns with high carbon content to increase the retention value; select shorter columns (e.g.15 cm,7.5 cm) to improve separation efficiency; select small particle size filler to improve separation; columns with large diameter fillers are used for components with large molecular weight. Furthermore, the HPLC column cannot recoil, only when the producer indicates that the column can recoil, the impurities left in the column can be removed by recoil.