Pheromones SPME

Abstract A relatively small number of mammalian pheromones has been identified, in contrast to a plethora of known insect pheromones, but two remarkable Asian elephant/insect pheromonal linkages have been elucidated, namely, (Z)-7-dodecen-1-yl acetate and frontalin. In addition, behavioral bioassays have demonstrated the presence of a chemical signal in the urine of female African elephants around the time of ovulation. Our search for possible ovulatory pheromones in the headspace over female African elephant urine has revealed for the first time the presence of a number of known insect pheromones. This search has been facilitated by the use of a powerful new analytical technique, automated solid phase dynamic extraction (SPDE)/GC-MS, as well as by novel macros for enhanced and rapid comparison of multiple mass spectral data files from Agilent ChemStation . This chapter will focus on our methodologies and results, as well as on a comparison of SPDE and the more established techniques of solid phase microextraction (SPME) and stir bar sorptive extraction (SBSE). 

More recently, solid phase microextraction (SPME) [22] has been applied to the analysis of bug pheromones, using two techniques. In the first, headspace volatiles are trapped on the SPME fiber, analogous to trapping on SuperQ [e.g., 23]. Alternatively, if the source of the pheromone is known, the SPME fiber can be wiped on the cuticle to directly adsorb the compounds [24]. In either case, the fiber is then thermally desorbed directly into a GC or GC-MS. Whereas this method is excellent for analysis, with good recoveries, it does not provide a sample that can be used for bioassays or for isolation of an active compound. 

The diterpene, Neocembrene A, or (l , 5A, 9A, 12i )-l,5,9-trimethyl-12-(l-methyl-ethenyl)-l,5,9-cyclotetradecatriene has been identified after SPME and GC-MS analysis as the major component of the trail-following pheromone of the Rhinotermitidae Prorhinotermitinae, Prorhinotermes canalifrons and P. simplex. In all other Rhinotermitidae studied so far, the major component of the trail pheromone has been dodecatrienol. Hydro-quinone was identified for the first time as a phagostimulating pheromone in the Australian termite species, Mastotermes darwiniensis. ... 

We have employed automated headspace SPME/GC-MS and SPDE/GC-MS in our search for elephant pheromones (41). Currently, we are developing a new... 

There are a wide variety of SPME fiber coatings available. Polymethylsiloxane fibers are useful for low to medium polarity compounds and are therefore suitable for most pheromones. Mixed coated fibers are available and these are possibly more suitable for a starting point as they offer complimentary properties and are therefore suitable for a wide range of compounds. The mixed coated poly-dimethylsiloxane-divinylbenzene fiber offers the broadest range of adsorption. 

GC-IR can permit the development of a GC/DD-FTIR interface to-date limited by its water sensitivity. As SPME is a rapid sampling device and permits a significant reduction of the duration of GC analysis (solvent-free), SPME-GC is especially interesting for living organisms. For instance, the sensitivity of SPME-GC/DD-FTIR allows one to follow the kinetics of pheromonal emission of an individual insect on-line. ... 

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