After 3-hour air
drying at room temperature, each piece was peeled using a
fruit peeler, and then the peel was further cut into smaller
pieces; a total of 5 g of apple peel was added to 10 mL of phosphate
buffer. The mixture was shaken vigorously by a stirrer
for 3 min and centrifuged for 5 min at 10 000 rpm. The supernatant
was collected from this mixture as the extracted solution
for subsequent pesticide detection.