Fast Trace Detection of Chlorpyrifos Vapors Using a Handheld Ion Mobility Spectrometer Operated near Ambient...

Area of Science:

• Analytical Chemistry
• Environmental Science
• Forensic Science

Background:

• Chlorpyrifos (CPF) is a widely used organophosphorus pesticide with significant toxicity concerns.
• CPF exposure can lead to acute intoxications and chronic neurological effects.
• There is a need for sensitive and portable methods for CPF detection.

Purpose of the Study:

• To develop and validate a method for the qualitative and quantitative detection of Chlorpyrifos vapors.
• To assess the performance of a pocket-held Time-of-Flight Ion Mobility Spectrometer (ToF IMS) for CPF analysis.
• To establish the sensitivity and quantification limits for CPF detection.

Main Methods:

• Utilized a Smiths Detection LCD-3.2E ToF IMS with ammonia doping.
• Operated the instrument near ambient temperature (<30 °C).
• Analyzed CPF vapor spectra in positive ion mode, identifying characteristic product ion peaks.

Main Results:

• Identified two distinct product ion peaks for CPF: monomer M·NH4+ (K0 ≈ 1.76 cm2 V-1 s-1) and dimer M2·NH4+ (K0 ≈ 1.47 cm2 V-1 s-1).
• Achieved a limit of detection (LOD) of 0.72 ppbV (10.5 μg m-3) and a limit of quantification (LOQ) of 2.41 ppbV (35.1 μg m-3).
• Demonstrated linear response up to 100 ppbV, with saturation above approximately 1000 ppbV.

Conclusions:

• The ToF IMS method provides a robust tool for detecting and quantifying trace levels of CPF vapors.
• This technique has significant implications for industrial hygiene, forensic investigations, and environmental monitoring of organophosphorus pesticides.
• The portability and sensitivity of the instrument allow for both off-site and on-site analysis.