Comprehensive analysis of airborne pesticides using hard cap espresso extraction-liquid chromatography-high-resolution mass spectrometry

- Hard cap espresso extraction has been employed for pesticide analysis from PM10.
- A NaCl salting out step allowed a fast and easy pesticide preconcentration.
- The proposed method was validated with a MAE reference methodology.
- Pesticide levels found in air were in the 8.1-60 pg m−3 range.
- Non-target pesticide metabolites were identified by retrospective analysis of extracts.

A hard cap espresso extraction procedure has been developed to recover airborne pesticides in particulate matter trapped in filters. This extraction step was made for 20 s at 72 °C and 19 bar using 50 mL of 20% (v/v) acetonitrile in water. After that, based on NaCl salting out, extracts were concentrated 22 times and analysed by ultra-high performance liquid chromatography - high resolution mass spectrometry. 35 pesticides were evaluated, as a proof of concept, being validated the whole methodology and compared the extraction method with that based on microwave assisted extraction for 20 min. In short, the method avoids cross-contamination of samples, it is relatively fast and consumes only 10 mL acetonitrile and 8 g NaCl per sample; thus, offering a low cost and green alternatively to available methods based on pressurized solvent extraction or microwave-assisted treatment.