Direct detection of chlorpropham on potato skin using desorption electrospray ionization

Abstract

Most pesticides, herbicides and other plant treatment agents are applied to the crop surface. Direct mass spectrometric methods, such as desorption electrospray ionization (DESI), offer new ways to analyze plant samples directly and rapidly. A strategy for the development and optimization of a DESI method for the direct determination of chemicals on complex surfaces is described. Chlorpropham (CP) was applied to potato surfaces as an example for a crop protection agent and analyzed using a self-made DESI source. Aspects such as instrument selectivity, sensitivity and reproducibility were investigated. The MS(4) fragmentation pattern of CP was analyzed to achieve the necessary detection selectivity, and is discussed in detail. Similar fragmentation was found in the ESI and DESI mass spectra, indicating that the mechanisms of ESI and DESI are closely related. A DESI method for semi-quantification of CP on potatoes was developed. Detection limits of 6.5 µg/kg were found using MS/MS. The reproducibility, in the range of 12% (signal variation), appears to be sufficient for semi-quantitative measurements.

The quantitative surface analysis of an antioxidant additive in a lubricant oil matrix by desorption electrospray ionization mass spectrometry

“…Since the development of DESI in 2004, it has become one of the most commonly used techniques for the qualitative surface analysis of target analytes, and has been applied to the detection of a wide range of compounds desorbed from a variety of surface materials . The use of DESI mass spectrometry (DESI‐MS) in quantitative analyses remains relatively unexplored, but has been reported for the analysis of complex matrices such as biological fluids, foodstuffs, polymers, and cosmetic formulations, showing the potential of the technique.…”

Macroscopic and microscopic spatially-resolved analysis of food contaminants and constituents using laser-ablation electrospray ionization mass spectrometry imaging

“…In other situations, microscopic imaging will be required to localize the presence of harmful natural toxins more precisely, not only for food quality and safety decisions but also to support further research into the formation and fate of natural toxins. The ease of use of LAESI-MSI is in contrast with alternative DESI, nanoDESI, and MALDI imaging studies of cell cultures, potato, rice, and beef [ 15 , 35 – 37 ]. However, some LAESI-specific disadvantages should also be mentioned.…”

Rapid determination of multiclass fungicides in wine by low-temperature plasma (LTP) ambient ionization mass spectrometry

“…In this sense, the requirements of food-quality and safety-testing elds map well against the features of ambient ionization mass spectrometric techniques. Different applications dealing with the use of a wide range of ambient MS methods for various food analysis applications have been recently described in published reports, [12][13][14] particularly based on the use of commercially available ambient MS methods such as desorption electrospray ionization mass spectrometry (DESI-MS) [15][16][17] and direct analysis in real time (DART). [18][19][20][21][22][23][24] Among the available ambient desorption/ionization mass spectrometry (MS) methods developed so far, low-temperature plasma (LTP) 25 is a plasma-based approach 26,27 that permits direct and rapid ambient ionization and mass analysis with minor sample workup.…”