Gemini Position

Various classes of cationic surfactants, including quats, esterquats, alkyl ethoxy amines, quaternary perfluoroalkyl ammoniums and gemini surfactants have been analysed extensively with LC—MS and LC—MS—MS techniques, and their spectra have been fully characterised. Different ionisation methods have been applied for the detection of such surfactants, including API techniques (APCI and ESI) in negative and positive modes of operation. In addition, detailed examples regarding MS—MS fragmentation of these compounds have been reported and presented in this chapter. 

The technology supporting gemini surfactants has been in existence for more than 20 years and they are so-called because they have two hydrophobic head groups and two hydrophilic groups in the same molecule. The two portions of the molecule are linked by a spacer which can be attached directly to the two ionic groups or can be positioned down the hydrocarbon chain as shown in Figure 5.3, positions 1 and 2 respectively. 

In this book, whenever 1 refer to a planetary position such as the one in the preceding example, 1 describe it as 26°23 Gemini. I usually don t spell out the words degree (°) and minute ( ). I assume that you know them. On birth charts, 1 go further and omit those two tiny symbols. Instead, the charts in this book announce planetary positions by using boldface type for the degrees and regular type for the minutes, as follows 26 23. 

Polarity Positive Quality Mutable Element Fire Symbol The Centaur Ruling Planet Jupiter Opposite Sign Gemini... 

All the solutioit NMR measurements were performed at ambient probe ten rattue using S mm o.d. san e tubes. Solution H and C NMR plectra m DMF-removed from sai les by freeze mnp ttew cycles. The chemical shifts are reported taking as a reference the chemical fr positions of the solvent with respect to TMS. 

Pyridinium gemini surfactants possess two positive charges, a high charge/mass ratio (loading capacity) and a high molecular flexibility. In Hies et al. research [76],... 

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