Design of a UA-DSPME method for extraction and determination of ECR.
The ECR extraction equilibrium from water samples was achieved within 5 min.
Experimental conditions of UA-DSPME were optimized through central composite design.
Satisfactory repeatability, low LOD (0.43 ng mL−1) and wide linearity (5–2000 ng mL−1) were achieved.
Ultrasound significantly reduces contact times for ECR extraction.