Introduction

Rare earth elements such as neodymium are widely present in nature and may be mixed in trace amounts during the production of cosmetics. According to the latest issued "Technical Specification for Cosmetics Safety"

According to the 2015 edition, 15 rare earth elements including neodymium are classified as restricted components. normal

The use of cosmetics containing trace amounts of rare earth elements has lower health hazards for consumers, but rare earth elements exceeding a certain level can have certain biological toxicity, and long-term exposure can cause harm to the human body. For example, rare earth elements are obvious liver toxins that can interfere with the metabolism of sugars, fats, proteins, nucleic acids, and drugs. After rare earth element poisoning, skin symptoms such as folliculitis, itching, dryness, and pigmentation often occur. Among them, neodymium has strong irritation to the eyes and mucous membranes, moderate irritation to the skin, and long-term absorption can also lead to pulmonary embolism and liver damage.

Experimental Section

sample pretreatment

Weigh 0.1-0.3 g of sample, accurate to 0.0001 g, and place it in a PTFE PTFE high-pressure digestion tank that has been acid boiled and washed. Add 5 mL of nitric acid

(A small amount of hydrofluoric acid needs to be added if necessary), 2 mL of hydrogen peroxide solution. Cover and place the digestion tank on an electric heating plate for pre digestion (80 ° C) for 30-40 minutes, then allow it to fully digest

Cooling. Heat and digest according to the pre-set digestion program of the microwave digestion instrument. After the digestion program is completed, cool down to room temperature, open the digestion tank, transfer the sample digestion solution to a clean 50 mL polyethylene terephthalate (PET) plastic bottle, wash the digestion tank and lid 3-4 times with a small amount of water, merge the washing solution into the PET bottle, weigh to 50.00 g, and mix well. Conduct a blank test along with the sample.

experimental results

Drawing of standard curve: Prepare 0.00, 0.50, 1.00, 5.00, 10.0, 20.0, 50.0, and 100 µ g/L series standard solutions for all elements and draw the standard curve.

Detection limit of 15 rare earth elements including neodymium in cosmetics by ICP-MS method (unit: µ g/L)