Ultra-trace lead-cadmium ion detection method and detection test strip

The invention discloses an ultra-trace lead-cadmium ion detection method and a detection test strip. The detection method comprises the following steps: (1) acidifying a sample; (2) removing Hg2+ and Zn2+ in the sample; (3) diluting the sample by utilizing a buffer solution to obtain a neutral sample; (4) enabling the neutral sample obtained in the step (3) to be contacted with dithizone to generate a lead-cadmium ion-dithizone complex; (5) adding sulfide solution so as to enable the lead-cadmium ion-dithizone complex to be completely reacted to generate PbS and/or CdS; (6) carrying out silver staining reaction on the mixture containing PbS and/or CdS obtained in the step (5), and determining the concentration of lead and cadmium ions in the to-be-detected sample according to the grey scale of a reaction product. The test strip comprises a substrate film and a dithizone layer, wherein the dithizone layer is compounded onto the substrate film, and the test strip is packaged in a vacuum manner. The detection method and the detection test strip are sensitive inn detection, simple in judgment, capable of reaching the standard of naked eye detection, strong in applicability and stable inn performance.