Reversed-phase chromatography bonding chemistries

For reverse-phase chromatography purposes, silica sorbents are commonly modified by hydrophobic ligands by means of silanes. These systems are therefore particularly suitable for water intrusion experiments [7]. We studied the influence of the chain nature (perfluorated, alkyl), the chain length and the type of bonding chemistry (mono or trifunctional, chloro- or alkoxy- silanes) on the hydrophobic properties of silica gels. 

The focus is on concepts in reversed-phase liquid chromatography (RPLC), though the same concepts are usually applicable to other modes of HPLC. International Union of Pure and Applied Chemistry (IUPAC)10 nomenclature is used. The term sample component is often used interchangeably with analyte and solute in the context of this book. As mentioned in Chapter 1, the most common stationary phase is a hydrophobic C18-bonded phase on a silica support used with a mixed organic and aqueous mobile phase. The terms packing and sorbent often refer to the bonded phase whereas solid support refers to the unbonded silica material. 

Capillary gas chromatographic methods are described for the analysis of chemically bonded reversed-phase HPLC stationary phase materials. Procedures for acid digestion of the packing material producing stable and volatile derivatives easily analyzed by gas chromatography are compared for precision and accuracy. The methods were used to analyze a variety of commercial phases, possessing widespread monofunctional silane chemistries and bonding consistencies. 

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