# Supercritical Carbon Dioxide Extraction With Dimethyl Carbonate and Bio‐Ethanol as Co‐Solvents for the Determination of Pesticide Residues in Black Pepper by Low‐Pressure Gas Chromatography–Triple Quadrupole Mass Spectrometry

## TL;DR

This paper introduces a green extraction method using supercritical carbon dioxide with eco-friendly co-solvents to detect pesticide residues in black pepper, offering a reliable and efficient alternative.

## Contribution

The study introduces a novel green extraction method using dimethyl carbonate and bio-ethanol for pesticide residue analysis in black pepper.

## Key findings

- Extraction with 10% dimethyl carbonate achieved 92.6% average recovery of 44 pesticides.
- The method met EU maximum residue levels with detection and quantification limits below regulatory thresholds.
- Quinalphos was found to exceed EU MRLs in commercial black pepper samples.

## Abstract

The determination of pesticide residues in spices is analytically challenging due to their high content of essential oils and secondary metabolites that could interfere with detection and quantification. In this study, supercritical fluid extraction (SFE), using green co‐solvents, was evaluated for the extraction of 44 pesticides from black pepper (Piper nigrum). The extraction performance of bio‐ethanol (bio‐EtOH) and dimethyl carbonate (DMC) was compared under mild operating conditions. Optimal recoveries were obtained with 10% DMC, yielding an average of 92.6% across 44 pesticides, comparable to 93.7% using bio‐EtOH. Method performance was assessed by low‐pressure gas chromatography–triple quadrupole mass spectrometry (LP‐GC‐QqQMS). Linearity was achieved over the tested range, with limits of detection (within the range 0.1–17.9 µg kg−1) and quantification (within the range 0.3–59.8 µg kg−1) always below European Union (EU) maximum residue levels (MRLs). Accuracy ranged from 74.4% to 107.7%, with intra‐day precision between 0.8% and 16.1%. A pronounced matrix effect was observed (average ionization suppression: −47.6%). The application of the validated method to commercial black pepper samples revealed the presence of diphenylamine, quinalphos, and phosalone, with only quinalphos exceeding EU MRLs. These findings demonstrate that SFE with DMC as a co‐solvent provides an efficient, greener, and reliable extraction approach for multi‐residue pesticide analysis in a complex spice matrix. The combination of SFE with LP‐GC‐QqQMS supports the implementation of greener and high‐throughput monitoring workflows for complex spice matrices.