Nickel Release Test

1. Introduction to Nickel Release

Nickel is an element that can easily cause contact allergies. When nickel is released from nickel-containing materials and comes into prolonged contact with the skin, it can be absorbed and cause allergic reactions in some individuals. Furthermore, exposure to soluble nickel salts can lead to systemic allergic contact dermatitis (statistics show that 20% of people exhibit significant allergic reactions to nickel). Currently, for daily consumer goods such as clothing and jewelry exported to Europe, if they contain nickel-based metal accessories, testing for nickel release levels is generally required.

The European Union adopted Directive 94/27/EC (Nickel Release Directive) in 1994 to regulate the use of nickel (Ni) in products that come into direct and prolonged contact with the skin, such as necklaces, bracelets, watch cases, watch straps, metal eyeglass frames, metal casings of consumer electronics (e.g., MP3 players, digital cameras), and metal buttons. The reason for this regulation is that nickel can cause skin allergies.

According to this directive, the nickel release rate must not exceed 0.5 micrograms per square centimeter per week.

Since July 20, 2000, EU member states have prohibited the manufacture and import of products that do not comply with this directive.

On July 20, 1997, the EU published three harmonized standards—EN 1810, EN 1811, and EN 12472—in accordance with the requirements of Directive 94/27/EC, specifying quantitative analysis methods for nickel release levels.

2. Nickel Release Limit Requirements

European standards specify that the nickel release rate for products such as clothing and jewelry must not exceed 0.2 μg/cm2/week. On July 20, 1997, the EU published two new harmonized standards, EN 1811 and EN 12472, in accordance with Directive 94/27/EC, clarifying the quantitative analysis methods for nickel release levels.

3. Principle of Nickel Release Testing

The test object for nickel release is immersed in artificial sweat solution for one week. The concentration of dissolved nickel in the solution is then analyzed using atomic absorption spectroscopy, inductively coupled plasma spectroscopy, or other suitable analytical methods.

4. Nickel Release Testing Methods

Total Nickel Content Test (EN 1810:2005);

Nickel Release Test for Products in Direct and Prolonged Contact with Skin (EN 1811:1999, applicable to products without electroplated coatings);

Test for Nickel Release After Catalysis and Abrasion of Coated Items (EN 12472:2005, applicable to coated products).

5. Nickel Release Test Items