US EPA

7740553 

Journal Article 

Dynamic headspace analysis of floral volatiles: a comparison of methods 

Raguso, RA; Pellmyr, O 

1998 

1 

Oikos
ISSN: 0030-1299
EISSN: 1600-0706 

Blackwell Publishing Ltd 

81 

2 

238-254 

English 

10.2307/3547045 

WOS:000071918100004 

Lack of standardization of floral scent analysis using dynamic headspace collection and GC-MS has prevented meaningful biological comparisons of results from different studies. We explored technique-related sources of variation by comparing the relative performances of different trapping sorbents, elution solvents and vacuum pump flow rates in the collection of known volatiles from (a) synthetic blends on filter papers and (b) living flowers of Clarkia breweri (Onagraceae). The greatest amounts of volatiles were collected when Porapak Q sorbent and hexane solvent were used, but most analyses were qualitatively similar. Low and high pump flow rates yield a tradeoff, with higher rates trapping low volatility compounds but also raising ambient contamination levels. Significant variation was associated with the use of different sorbents and solvents, but detailed statistical comparisons were precluded by significant interaction effects involving other experimental variables. Given the tightly controlled experimental conditions and use of inbred plant lines, this unexpected result suggests that analyses of small samples carry a high risk of experimental artifact. We recommend that floral scent analyses incorporate experimental and statistical approaches that address as many method-related variables as possible, that samples of 10 or more individuals be used, and that GC-MS parameters be held constant for all comparative analyses.