Facile fabrication of flexible AuNPs@CDA SERS substrate for enrichment and detection of thiram pesticide in water

•The flexible AuNPs@CDA SERS substrate prepared was inexpensive and environmentally friendly.•Two test methods (drop-test and enrichment-test) based on the flexible AuNPs@CDA SERS substrate has been developed.•The enrichment-test has a lower detection limit than the drop-test.•The limits of detection of the thiram pesticide in water reaches 10−7 g/mL by the enrichment-test.•The enrichment-test has a good linear relationship from 10−7 g/mL to 10−6 g/mL for the detection of thiram pesticide in water.