Process optimization of microwave-assisted extraction (MAE) of polycyclic aromatic hydrocarbons (PAHs) from leaves of Murraya paniculata (L.) Jack: Process intensification approach

Abstract

Pervasiveness of polycyclic aromatic hydrocarbons (PAHs) in environment results in threatening health implications and ecological catastrophes. The study was aimed at developing a process intensified extraction route for isolation of PAHs from leaves of an established plant biomonitor, Murraya paniculata (L.) Jack. Microwave-assisted extraction (MAE) was targeted and its parameters were optimized through response surface methodology (RSM) incorporating Box-Behnken Design (BBD) in maximizing extraction yield of PAHs. Instrumental analysis of PAHs was validated based on desirable data of precision (RSD<1–2 %), accuracy (78–99 % recovery), LOD (0.001–0.003 µg g^-1) and LOQ (0.03–0.09 µg g^-1). Solvent selection through screening experiments followed by single factor analysis for solvent-to-sample ratio (V/W), extraction time and extraction temperature was carried out. In RSM, experimental and predicted response values showed a good fit for quadratic model and significance of the regression model was confirmed through analysis of variance (ANOVA) (F: 428.74; p < 0.0001). Extraction yield was maximized for extraction temperature: 45.77 °C, extraction time: 11.67 min and solvent-to-sample ratio: 22.64 mL g^-1 with 98 % model accuracy. A comparison between Soxhlet and MAE highlighted the consumption of 1.8 fold higher volume of solvent, requiring 30 times more extraction time with high energy input in Soxhlet method, suggesting the intensified performance of MAE.