Nickel is an element that easily causes contact allergy. Nickel is released by some nickel-containing substances, which will be absorbed by the skin after long-term contact with the skin, thus causing some individuals to be allergic. Further exposure to soluble nickel salts will lead to contact dermatitis (according to statistics, 20% people have obvious allergic reaction symptoms to nickel). At present, if the materials of clothing, jewelry and other daily necessities exported to Europe contain metal ornaments containing nickel, it is generally necessary to detect the release of nickel. \x0d\ nickel release instruction (94/27/EC) effective date: 1999-0 1-20 product range: children's products, including metal rivets, buttons, fasteners, zippers, metal plates and labels on toys or children's clothes \x0d\ nickel release instruction (94/2000) For the above reasons, the European Union proposes to restrict the use of nickel metal in certain articles. 1On June 30th, 994, the European Union issued the directive 94/27/EC. The amendment 12 of directive 76/769/EEC requires that the release amount of nickel in nickel-containing products should not exceed 0.5μg/cm2/ week1July 20th, 997. According to the requirements of EU 94/27/EC, EN18/kloc-0+. 〉1811and EN 12472 determined the standard quantitative analysis method for nickel release. \x0d\CTS East China Laboratory: Ningbo 0574-879121-837; CTS South China Laboratory: Guangzhou 020-85543113-801. Test process: put the nickel release to be tested into the artificial sweat test solution for 7 days. The concentration of dissolved nickel in the solution is measured by atomic absorption spectrometry, inductively coupled plasma spectrometry or other suitable analytical methods. The release amount of nickel is μ g/cm2/week (ug/cm2. The implementation of directive \x0d\94/27/EC is that manufacturers and importers are no longer allowed to supply products with unqualified nickel release after six months after the European Standards Committee has adopted standards to prove all test methods consistent with the directive. /kloc-After 0/8 months, it is not allowed to be sold to the final consumer.