Overview of data from heavy metal detection instruments in cosmetics

　　Detection principles and standards for various heavy metals

　　1. Detection principle and adopted standards of heavy metal arsenic

　　The national standard borohydride reduction colorimetric method is used, that is, after the sample is digested, potassium iodide-thiourea is added and heated to reduce pentavalent arsenic to trivalent arsenic. Under acidic conditions, potassium borohydride reduces trivalent arsenic to negative trivalent arsenic to form arsenic hydrogen, which is introduced into the absorption liquid to appear yellow. The arsenic content is determined by instrument detection.

　　2. Detection principles and standards for heavy metal lead

　　The national standard disulfide hydrazone colorimetric method was used, that is, after the sample was digested, lead ions reacted with disulfide hydrazone under weak alkaline conditions to form a red complex, which was dissolved in chloroform and then determined colorimetrically.

　　3. Detection principle and adopted standards of heavy metal chromium

　　After the sample is digested, in the presence of divalent manganese, chromium ions react with diphenylcarbazide to form a purple-red complex. The depth of the complex color is proportional to the hexavalent chromium content, and the chromium content can be obtained by colorimetric determination.

　　4. Detection principle and adopted standards of heavy metal cadmium

　　The national standard colorimetric method was used, that is, after the sample was digested, cadmium ions reacted with 6-bromobenzothiazole azonaphthol under alkaline conditions to form a red complex, which was dissolved in chloroform and then determined colorimetrically.

　　5. Detection principles and standards for heavy metal mercury

　　The national standard disulfide hydrazone colorimetric method was used, that is, after the sample was digested, mercury ions and disulfide hydrazone formed an orange-red complex under acidic conditions, which was dissolved in chloroform and then determined colorimetrically.

　　6. Detection principle and adopted standards of heavy metal nickel

　　The national standard dimethylglyoxime colorimetric method is used, that is, after the sample is digested, a peroxidant is added under strong alkaline conditions, and nickel and dimethylglyoxime form a reddish-brown complex. The color depth of the complex is proportional to the nickel content, and the nickel content can be obtained by colorimetric determination.

　　7. Detection principle and adopted standards of heavy metal iron

　　After the sample is digested, the iron is reduced to divalent iron with a reducing agent. In the pH range of 2-9, the divalent iron reacts with o-phenanthroline to form an orange-red complex. The color depth of the complex is proportional to the iron content, and the iron content can be obtained by colorimetric determination.

　　8. Detection principles and standards for heavy metal aluminum

　　The national standard chrome azuro blue S colorimetric method is used. After the sample is digested, the trivalent aluminum ions react with chrome azuro blue S and hexadecyl ammonium bromide in the buffer solution medium to form a blue ternary complex. The color depth of the complex is proportional to the aluminum content, and the aluminum content can be obtained by colorimetric determination.

　　9. Detection principle and adopted standards of heavy metal zinc

　　The national standard disulfide hydrazone colorimetric method is used. After the sample is digested, under appropriate pH conditions, zinc ions and disulfide hydrazone form a purple-red complex. The color depth of the complex is proportional to the zinc content, and the zinc content can be obtained by colorimetric determination.

　　10. Detection principle and adopted standards of heavy metal manganese

　　After the sample is digested, the divalent manganese ions in the test solution are oxidized to purple-red permanganate with an oxidant of appropriate strength under acidic conditions and then colorimetric determination is performed. The manganese content can be obtained by colorimetric determination.