# Rapid In-Field Volatile Sampling for Detection of _Botrytis cinerea_ Infection in Wine Grapes
###### Abstract
The unique characteristics of MOFs were used to adsorb toxic components from contaminated environments for remediation [20; 21] and to lower detection limits for rapid and direct mass spectrometry analyses [22]. MOF-5 [23] was packed in quartz tubes for the in-field collection and quantification of formaldehyde, and this procedure has shown excellent stability, adsorption efficiency, and reproducibility [24]. Mixtures of aldehydes were also detected and quantified using different structured MOFs coupled with thermal desorption GC-MS and compared with a commercial absorbent, Tenax(r)-TA [25]. These applications demonstrate the range of potential usage of MOFs extraction for GC-MS in wine characterisation. In-field static volatile sampling from plant material was performed using SPME fibres for monitoring volatiles from single grape berries and bunches of grapes in which the sampling environment was protected using glass enclosures or polyvinyl fluoride plastic bags for the duration of sampling [26]. Enclosed environments used with SPME sampling have also been created using inverted glass funnels placed over flowers to enable the monitoring of volatile emission during flower development. Static headspace sampling is an easy and non-destructive volatile collection method that is suitable for in situ fingerprint profiling and quantitative analysis of VOCs. However, the required sampling time with enclosed samples is typically very long, up to 1 day each, which substantially increases the confounding impacts of airspace humidity and heat accumulation upon volatile expression from the sample and absorption efficiency. Rapid volatile sampling methods are appropriate for high-throughput sample analysis. The reduction of sampling time can be achieved using low vacuum devices to draw air through a sampling tube packed with solid-phase material, and such devices have been deployed for a volatile sampling of Meyer lemon citrus trees and plant VOCs, enabling the detection of \(\alpha\)-pinene, limonene, linalool and \(\alpha\)-terpineol with as sampling duration as short as 5 min [27]. In another study, a commercially available SPME syringe coupled with an air-sampling pump was used to collect volatiles from lavender plants, _Lavandula angustifolia_ and _Lavandula \(\times\) intermediia_,thereby enabling species discrimination followed by a portable GC-MS for in-field volatile analysis with a 5-min sampling time and 3-min chromatographic separation [28]. An advantage of air-sampling pumps is that they produce a constant low flow rate at around 50 mL/min, allowing enough time for absorption materials to trap volatile compounds. These dynamic, volatile sampling methods allow for rapid sample extraction and analysis, demonstrating potential application for in-field or point-of-sample volatile monitoring for fruit quality assessment. The aim of the current work was to develop a rapid, volatile sampling method for wine grapes that could be used prior to harvest to detect and measure _B. cinerea_ infection. Sampling tubes with zeolitic imidazolate framework-8 (ZIF-8) crystal were applied for volatile in-field sampling and then analysed using thermal desorption GC-MS. Using a low-flow rate pump, volatile metabolites of interest were collected in 15 min for each sample, and the commercially available material Tenax(r)-TA was used for extraction, simultaneously, as a comparison.