An ultrasound assisted modified solid phase micro-extraction technique for enrichment of cadmium and lead in aqueous extract of coal gangue soil samples

•Ultrasound energy enhanced preconcentration efficiency of targeted analytes using advance extraction methodology.•The novel DES based microextraction was developed to overcome hazardous effects of conventional reagents.•The CGS have higher levels of lead under investigation as compared to cadmium.•Proposed method has the advantages of being simple, safe, greener and economical.