Structural Elucidation of Agrochemicals and Related Derivatives Using Infrared Ion Spectroscopy

Area of Science:

• Environmental Chemistry
• Analytical Chemistry
• Spectroscopy

Background:

• Agrochemicals transform in the environment, creating derivatives with unknown toxicity and persistence.
• Identifying specific isomers of these derivatives is crucial but challenging using current methods like liquid chromatography-mass spectrometry and nuclear magnetic resonance (NMR) spectroscopy.
• Existing techniques face limitations in structural correlation and sensitivity, hindering accurate identification of environmental transformation products.

Purpose of the Study:

• To demonstrate the identification of hydroxylated derivatives of plant protection compounds (azoxystrobin and benzovindiflupyr) in food matrices.
• To showcase infrared ion spectroscopy as an effective alternative for characterizing agrochemical derivatives.
• To enable the identification of environmental transformation products without relying on physical reference standards.

Main Methods:

• Utilized infrared ion spectroscopy, an orthogonal tandem mass spectrometry technique.
• Combined the sensitivity and selectivity of mass spectrometry with structural information from infrared spectroscopy.
• Employed computational prediction of infrared spectra for candidate molecular structures.

Main Results:

• Successfully identified hydroxylated derivatives of azoxystrobin and benzovindiflupyr in tomato and spinach matrices at low levels.
• Demonstrated the capability of infrared ion spectroscopy to provide structural information for accurate compound identification.
• Validated the use of computationally predicted IR spectra for tentative identification of unknown agrochemical derivatives.

Conclusions:

• Infrared ion spectroscopy offers a powerful and orthogonal approach for identifying complex agrochemical derivatives in environmental and food samples.
• This technique overcomes the limitations of traditional methods, providing enhanced structural elucidation capabilities.
• The ability to predict IR spectra facilitates the identification of environmental transformation products, even in the absence of reference standards, improving environmental risk assessment.