SIELC is well-known for its expertise in packing high-quality multi-mode HPLC columns with superior lot-to-lot reproducibility. For decades, liquid chromatography stationary phase design has been dominated by the idea of elimination of multiple, or "unwanted", interactions that occur in mixed-mode separations. A recent goal in reversed-phase chromatography has been to eliminate silanol interactions with some analytes by developing base-deactivated phases.
Within the same trend, adsorption interactions are considered undesirable as opposed to steric interactions in size-exclusion chromatography, and non-ionic interactions are generally viewed as complications in ion-exchange and ion-exclusion chromatography. However, there are ways to benefit from multiple interactions on the stationary phase.
SIELC Primesep, Obelisc, and Promix Mixed-Mode HPLC Columns
SIELC Technologies introduces new lines of silica based HPLC columns that exhibit superior retention for difficult to separate mixtures. Every SIELC column has a unique stationary phase, combining the properties of hydrophobic and ion-exchange stationary phases. Strong interaction between the two phases allows controlled retention of ionizable and neutral compounds independently. There is no tailing associated with silica surface chemistry.
We recommend starting with the best-selling Primesep 100 or Primesep D HPLC Columns
For the reversed-phase + cation exchange columns, we recommend starting with Primesep 100. The corresponding universal reversed-phase + anion exchange column is the Primesep D. If the universal Primesep 100 or Primesep D does not work well for your application, you can further refine the column selection to other Primesep columns. Please inquire about various method development kits.
Protein and peptide mixed-mode HPLC Columns - Promix SP, Promix AP, and Promix MP
Promix columns have C12 carbon chains with different ionizable groups. Selection is based on the properties of the molecules. For small peptides you can use Promix SP (100 A) and Promix AP columns (100A and 300A), for larger proteins with multiple basic groups you will need Promix MP column (300A and 800A). Promix SP and Promix AP separate and retain compounds based on reversed-phase and cation-exchange properties. Promix MP separate/retain compounds based on reversed-phase/anion-exchange or cation-exclusion properties.
SIELC HPLC Column Selection Guide - All SIELC columns have at least two separation modes
SIELC Column Names
Mixed-Mode Reversed Phase
Primesep A (strongest acidic) Primesep 100 (universal)
Primesep C (WCX RP & complex)
Primesep 500 (weakest acidic)