Method Validation and Evaluation of Safrole Persistence in Cowpea Beans Using Headspace Solid-Phase Microextraction...

Area of Science:

• Agricultural Science
• Analytical Chemistry
• Entomology

Background:

• Bioinsecticides offer sustainable alternatives for agricultural pest control.
• Limited data exists on the persistence of bioinsecticides in stored grains.
• Safrole, from Piper hispidinervum essential oil, is a potential bioinsecticide.

Purpose of the Study:

• Optimize and validate a method for safrole residue extraction and quantification in cowpea beans.
• Assess the persistence of safrole in treated cowpea beans.
• Evaluate safrole's suitability as a safe bioinsecticide for stored grains.

Main Methods:

• Headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-flame ionization detection (GC/FID) was employed.
• Extraction parameters (temperature, time, fiber type) were optimized.
• Method validation included selectivity, linearity, LOD, LOQ, precision, and accuracy assessment.

Main Results:

• The validated method demonstrated high sensitivity (LOD: 0.0057 μg kg⁻¹, LOQ: 0.019 μg kg⁻¹) and reliability (R² > 0.99, recovery 99.26–104.85%).
• Safrole residue levels in cowpea beans decreased significantly over time, falling below 1% of initial concentrations by day five.
• Concentrations ranged from 1.095 to 0.052 µg kg⁻¹ (contact) and 2.16 to 0.12 µg kg⁻¹ (fumigation).

Conclusions:

• The optimized HS-SPME-GC/FID method is effective for safrole residue analysis in cowpea beans.
• Safrole exhibits low persistence in cowpea beans, indicating its safety for use as a bioinsecticide.
• This research supports the use of natural insecticides like safrole in stored grain pest management.