Solid Phase Extraction Common Questions and Answers (part 1)
Hydrophilic lipophilic balance
“Hydrophilic-Lipophilic Balance (HLB), originally used to mean “the equilibrium relationship between hydrophilic groups and lipophilic groups in surfactant molecules.” At the beginning of the 21st century, the concept of “hydrophilic lipophilic balance” Introduced into SPE, the filler matrix is a polymer (such as polystyrene), the matrix is lipophilic, similar to C18, with reversed-phase retention; then bonded to the polymer matrix, such as pyrrolidone, with Hydrophilic, the group can enhance the retention ability of the filler to the polar compound, and maintain the water wettability of the filler to prevent the bed from drying out and improve the stability of the result;
Dima Technology’s ProElut PLS combines a hydrophilic group (pyrrolidone group) and a hydrophobic group (divinylbenzene), which retains both polar and non-polar compounds and is hydrophilic and lipophilic. Balanced characteristics. The same small column is Waters Oasis HLB.
The hydrophilic lipophilic balance column generally has the following characteristics:
A True versatility: balanced retention of hydrophilic and lipophilic substances, covering non-polar, weakly polar compounds, overcoming the disadvantages of poor retention of polar compounds by C18 adsorbents;
B Higher stability: water wettability, after the filler is activated, even if the bed is dry, the retention of the target by the adsorbent will not change;
C Wide pH range of application: The matrix of PLS is organic polymer rather than silica gel, which is stable in the range of pH 0-14, while the silica-bonded adsorbent is stable only in the range of 2-7.5;
D Higher adsorption capacity: It can retain more targets, effectively prevent the occurrence of “penetration phenomenon” and improve reproducibility;
E There is no secondary interaction: there is unbonded silanol on the surface of the silica-bonded adsorbent, and the retention of the basic compound is strong. The basic compound is treated with a silica-bonded adsorbent, and the recovery rate is usually low; PLS It is an adsorbent for organic polymer matrix, and there is no secondary interaction. It can be used for basic compounds to obtain satisfactory results.