Advances in Analytical Capability to Power Agrochemical Product Design

• Published in: Outlooks on pest management Vol. 29; no. 3; pp. 104 - 110
• Main Authors: Gaunt, Nicholas P., Thomson, Niall, Padia, Faheem, Seymour, Mark, Moger, Julian
• Format: Journal Article
• Language: English
• Published: Saffron Walden Research Information 01.06.2018; Research Information Ltd
• Subjects: Agrochemical; Agrochemicals; Approximation; Autoradiography; Biological activity; Biomonitoring; Chromatography; Coherent scattering; Crop; Crop yield; Crops; Droplets; Fluorescence; Food; Food security; Fungicides; Gas chromatography; Herbicides; Ingredients; Insecticides; Ions; Labeling; Labels; Lasers; Leaves; Liquid chromatography; Mass spectrometry; Mass spectroscopy; Microscopy; Nondestructive testing; Organic chemistry; Pesticide residues; Pesticides; Plant tissues; Pollutants; Product design; Proteins; Raman spectra; Real time; Research centers; Scanning electron microscopy; Scientific imaging; Selectivity; Spatial discrimination; Spatial resolution; Spectrometry; Spectroscopy; Stimulated Raman Scattering; Surfactants; Temporal distribution
• ISSN: 1743-1026; 1743-1034
• DOI: 10.1564/v29_jun_02

The rapid growth in global population exerts mounting pressure on farmers to grow more food. Agrochemicals, such as herbicides, fungicides and insecticides, are a key factor in improving crop yields and without them around 35% of the world's food could not be produced. The widespread use of newer and more effective products since the middle of the last century has increased food security and improved standards of living around the world. To enable further improvements and meet demand, the ability to monitor the movement of active ingredients and their interactions with co-formulants in planta would be hugely advantageous. Usually, agrochemicals are applied to a plant via an aqueous spray. When optimised, the spray can contain a complex mixture of components, such as surfactants and oils, which can improve the retention of the spray droplets to the leaf, the spreading of the droplets on the leaf surface and enhance uptake into the plant. Currently the effectiveness of these components is measured via time-consuming offline processes or by monitoring biological performance. A key enabler for developing improved agrochemical activity is the ability to track the spatial-temporal distribution of agrochemical compounds in living plant tissues (i.e. in planta). This report outlines the current state of the art and reviews the techniques that show the potential to meet the growing requirements of the agrochemical industry. The ideal technique would be non-destructive, provide real time video and quantification of active ingredients in planta without the need for fluorescent labelling which can perturb the biokinetics. It compares the available characterisation techniques and discusses the pros and cons. Multiple techniques are already used in the agrochemical industry to monitor the interactions of agrochemicals with crops, however, none of the current techniques alone can meet the demands of sensitive, non-destructive, high spatial resolution imaging in real time. Results gathered from many countries by the Codex Committee on Pesticide Residues showed the majority of the methods referred to pesticides amenable to gas chromatography (GC) or liquid chromatography (LC). These methods cover approximately 75% of the compounds in the Codex system and do not satisfy the in planta characterisation needs. Other techniques include Time-of-Flight Secondary Ion Mass Spectroscopy (ToFSIMS), Matrix-assisted laser desorption/ionisation (MALDI) and autoradiography, plus emerging methods such as spontaneous and coherent Raman scattering. The paper reviews the suitability of spectrometry, autoradiography, electron and microscopy to meet the in planta characterisation needs of the agrochemical industry. The agrochemical industry would benefit from a non-destructive, real-time characterisation technique with high chemical selectivity and high spatial resolution. Although many techniques meet some of these requirements, currently only CRS enables all to be met by a single measurement. The use of CRS techniques such as CARS and SRS enables the monitoring and imaging of active ingredients in planta, at video-rate speed without the use of potentially interfering labels