Measurement of volatile plant compounds in field ambient air by thermal desorption–gas chromatography–mass spectrometry

Abstract

Determination of volatile plant compounds in field ambient air is important to understand chemical communication between plants and insects and will aid the development of semiochemicals from plants for pest control. In this study, a thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) method was developed to measure ultra-trace levels of volatile plant compounds in field ambient air. The desorption parameters of TD, including sorbent tube material, tube desorption temperature, desorption time, and cold trap temperature, were selected and optimized. In GC-MS analysis, the selected ion monitoring mode was used for enhanced sensitivity and selectivity. This method was sufficiently sensitive to detect part-per-trillion levels of volatile plant compounds in field ambient air. Laboratory and field evaluation revealed that the method presented high precision and accuracy. Field studies indicated that the background odor of tea plantations contained some common volatile plant compounds, such as (Z)-3-hexenol, methyl salicylate, and (E)-ocimene, at concentrations ranging from 1 to 3400 ng m(-3). In addition, the background odor in summer was more abundant in quality and quantity than in autumn. Relative to previous methods, the TD-GC-MS method is more sensitive, permitting accurate qualitative and quantitative measurements of volatile plant compounds in field ambient air.

Field background odour should be taken into account when formulating a pest attractant based on plant volatiles

“…The plant volatile compounds in ambient air at tea plantations were collected and analysed as described by Cai et al . 46 . Air near the tea bush canopy was collected at a flow rate of 100 mL min −1 for 240 min (24-L samples) using a microprocessor-controlled air sampling pump (Mini-pump Σ30; Shibata, Japan) at 13:00 h. After collection, all samples were taken to the laboratory and analysed immediately.…”

Smells from the desert: Microbial volatiles that affect plant growth and development of native and non‐native plant species

“…Ideally, naturally occurring concentrations of mVOCs should be first measured and later tested to make experiments more ecologically relevant. However, not many quantitative measurements of volatiles from plants and their microbial communities have been undertaken yet, but novel technologies should help close this gap soon (Cai, Xu, Bian, Luo, & Chen, ; Martínez‐Jarquín, Herrera‐Ubaldo, de Folter, & Winkler, ).…”

Leaf odour cues enable non‐random foraging by mammalian herbivores

“…To test this, the next step will be to measure the qualitative and quantitative spatial changes to odours in natural landscapes. Methods such as thermal desorption‐gas chromatography‐mass spectrometry (TD‐GC‐MS) are now available to detect part‐per‐trillion levels of volatile plant compounds in field ambient air (Cai, Xu, Bian, Luo, & Chen, ), providing the means to map odour contours around food sources. A synthetic herbivore‐induced VOC in soybean fields attracted (or repelled) arthropods in a radius of c .…”

“…The ramifications of suppressed odour cues for foraging by mammal herbivores are globally relevant. VOC emissions from both green leaf volatiles and terpenes are altered by multiple stressors (Holopainen & Gershenzon, ) and often reduced by lower ambient temperature in cooler seasons (Cai et al., ; Hartikainen et al., ; Kivimaenpaa et al., ) with longer nights when visual cues may be ineffective. We expect a complicated but important interplay between foraging efficiency and changes in odour cue strength as temperature and light levels shift with day (and night) length, season, latitude and longer term with climate change.…”